Planet Earth EAPS 10000-001

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EAPS 10000-001 – Planet EarthProfessor L. Braile

2271 HAMP (CIVL), [email protected]: Foundations of

Earth ScienceLutgens and Tarbuck

8th Edition 2017

8th Edition, 2017

8th Edition, 2017

Course information available at:http://web.ics.purdue.edu/~braile/eas100/eas100home.htm

7th Edition, 2014



Earth Science, Lutgens and Tarbuck, 8th Edition, 2017

Intro section PPTs (through today) have been updated th PPT (i df f t) li (li k f thon the PPTs (in pdf format) online (link from the

course home page)

Handouts: Lecture Note Figures 1A , 1 and 2

Hw 1 - due Tu, 9/18, Hw 2 – due 9/27

Lecture Notes/PPTs for Intro section now online

Exam I is Tu, 9/25; will discus in class Th, 9/20: Exam I, studying for exam, Study Guide (online)

http://www.intellicast.com/Storm/Hurricane/AtlanticAnalysis.aspx http://www.intellicast.com/Storm/Hurricane/AtlanticSatellite.aspx?animate=true

September 16, 2015 M8.3 Earthquake off the coast of Chile

7 cm/yr convergence

SantiagoWe discussedthe 2010 EQ previously

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M7.1 earthquake, April 24, 2017

Santiago

About one M8 or greater EQ every 8 years along the west coast of South America!

September 16, 2015 M8.3 Earthquake off the coast of Chile

Feb. 27, 2010 M8.8 Eq

Tsunami, September 16, 2015 M8.3 Earthquake off the coast of Chile

Coquimbo tide gage (150km N of epicenter) is a good illustration that the first wave does not have to be the biggest and that tsunami last for hours. (Jascha Polet). Note: more than 6 waves with greater than 2 m height, large waves go on for hours (sometimes many hours), wave period is about 30 minutes. These characteristics are common in large tsunami.

See more at: http://ds.iris.edu/ds/nodes/dmc/specialevents/2015/09/16/illapel-chile/#sthash.jvH85kev.dpuf

The Dynamic Earth (just some facts for illustration of dynamic Earth)

Each year…

- Earth rotates on its axis 365 ¼ times.- Earth travels ~1 billion km in orbit around the Sun.- There are ~8 Atlantic hurricanes.

Th 800 U S t d- There are ~800 U.S. tornadoes.- ~50 volcanoes erupt in the world.- There are ~150 M6 or greater earthquakes.- The US consumes ~8 billion barrels of oil and

gas (~20 million barrels/day, ~22 barrels/person/year).

- ~400 million liters of oil is spilled (~10 times the Exxon Valdez oil spill)

The Dynamic Earth, Each year…The U.S. uses ~600 trillion liters

of water (~5000 liters/person/day).~450 million tons of sediment are deposited

in the Gulf of Mexico by the Mississippi River.~20 billion tons of CO2 are emitted (~5

tons/person/year for the US).E th h 85 illi l (t t l 7 65 billi )- Earth has ~85 million more people (total ~7.65 billion).

- U.S. has ~2.7 million more people (total ~328 million) - The National Science Foundation spends about $6.5

billion on research and education (Proctor and Gamble spends over $10 billion a year on advertising, and cigarette and auto manufacturers spend a few billion dollars a year on advertising; ExxonMobil quarterly profits in 2018 are ~$4 billion).

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http://www.nature.com/news/demand-for-water-outstrips-supply-1.11143

The Ogallala (or “high plains”) aquifer is a vast water supply used for drinking water and irrigation for agriculture in the great plains area. It supplies about 30% of all the irrigation water used in the U.S. The aquifer is being depleted at a

http://earthdesk.blogs.pace.edu/tag/ogallala-aquifer/http://www.csmonitor.com/Environment/Latest-News-Wires/2013/0827/Ogallala-aquifer-Could-critical-water-source-run-dry

aquifer is being depleted at a rate of about 8 times the rate of replenishment. A 2013 report by the USGS states that the aquifer is about 30% depleted and could have an additional 39% depletion in the next 50 years.

California Drought Effects, 2011-2014 (USA Today, 9/3/2014; Oroville is in Northern California)

Earth from Apollo 17, 1972.

Southward looking oblique view of Mare Imbrium and Copernicus crater on the Moon. Copernicus crater is seen almost edge-on near the horizon at the center. The crater is 107 km in diameter and is centered at 9.7 N, 20.1 W. In the foreground is Mare Imbrium, peppered with secondary crater chains and elongated craters dueand elongated craters due to the Copernicus impact. The large crater near the center of the image is the 20 km diameter Pytheas, at 20.5 N, 20.6 W. At the upper edge of the Mare Imbrium are the Montes Carpatus. The distance from the lower edge of the frame to the center of Copernicus is about 400 km. This picture was taken by the metric camera on Apollo 17. (Apollo 17, AS-2444)

Global topography, land areashttp://www.ngdc.noaa.gov/mgg/topo/globe.html

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Global topography (etopo1 – 1 arc-minute [1/60th of a degree] grid) http://www.ngdc.noaa.gov/mgg/global/global.html

Close-up of Global topography (etopo1 – 1 arc-minute [1/60th of a degree, ~2 km] grid) http://www.ngdc.noaa.gov/mgg/global/global.html

Ocean bathymetry (ocean bottom topography)http://www.ngdc.noaa.gov/mgg/image/global_topo_large.gif

ETOP2 topography image from NOAA https://www.ngdc.noaa.gov/mgg/global/relief/ETOPO2/ETOPO2v2-2006/Graphics/ETOPO2v2miller.pdf

ETOP2 topography image from NOAA https://www.ngdc.noaa.gov/mgg/global/relief/ETOPO2/ETOPO2v2-2006/Graphics/ETOPO2v2miller.pdf

Hurricane Florence from the International Space Station, 9/11/2018, https://www.space.com/41773-hurricane-florence-photos-from-space.html

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Hurricane Florence from the International Space Station, 9/11/2018, https://www.space.com/41773-hurricane-florence-photos-from-space.html http://www.intellicast.com/Storm/Hurricane/AtlanticAnalysis.aspx

http://www.intellicast.com/Storm/Hurricane/AtlanticSatellite.aspx?animate=true

Earth Science (Geology) Section(Important concepts for today)

Rock SamplesThe Dynamic EarthEarth Materials

MineralsRocks (aggregates of minerals)

IgneousSedimentaryMetamorphic

The Rock CycleEarth’s Interior Structure and Composition

Earth Materials:

Mineral:Naturally occurring, inorganic solid, distinct chemical composition, regular crystal structure, characteristic physical properties. Examples: quartz, calcite, mica, feldspar, olivine, diamond, pyritep py

Rock:Aggregate of minerals.

Igneous, sedimentary, metamorphic.

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If you have interest in minerals and rocks, you can purchase mineral and rock kits for a reasonable price. They also makeThey also make good gifts for younger brothers and sisters or nieces and nephews. The samples are small but large enough to see the properties of each sample.

Hematite (Fe2O3)

Pyrite (FeS2)Minerals:

Quartz (SiO2)

Olivine ([Mg,Fe]2SiO4)

Giant gypsum (mineral) crystals from the Cave of Crystals, Chihuahua, Mexico (Figure, page 22-23, Text)

Olivine – an important silicate mineral (iron/magnesium silicate) in the )Earth’s mantle (the mantle is 82% of the planet by volume).

Mineral:Characteristic physical properties – hardness, crystal structure, cleavage, color streak, density

(Figure 1 15a text)(Figure 1.15a, text)

Mineral:Characteristic physical properties – hardness, crystal structure, cleavage, color streak, density

(Figure 1.15b, text)

(Figure 1 15b text)(Figure 1.15b, text)

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Mineral properties: Regular crystal structure (atomic scale) results in characteristic crystal shape and cleavage (Figure 1.2, text).

Crystal form and cleavage

Density

Streak

Mineral properties: Crystal formand cleavage, streak, density(Figures 1.10, 1.11, 1.14,, text).

September 19, 2017 – Exam I Information:

(Note: Lecture Topics Outlines/PPTs link (on the EAPS 100 home page) includes outlines of the lecture material, information about the most important topics and illustrations in the textbook [assigned reading] and pdf copies of nearly all of the PowerPoint slides shown in class –IntroNotes.pdf (updated) and EarthNotes.pdf (updated through Plate Tectonics).

Also, see the Study Guide to the Textbook available on the Handouts page on the course website and at: http://web.ics.purdue.edu/~braile/eas100/studyguide8th.pdf

EAPS 10000 001, Planet Earth

(Sept. 19, 2017; this information is also on the Announcements link on the EAPS 100 Home Page)

EXAM ITuesday, Sept. 25, 12:00-1:15 p.m., EE 129

1. Material presented in class through Sept. 20 (Intro section, Earth section through discussions of Plate Tectonics – see syllabus for schedule, topics and assigned textbook reading pages).

2. Because we will be covering hurricanes later in the semester, there are PPTs on the IntroNotes.pdf file, but that material will not be on Exam I.

3. You may use one 3”x5” (That’s ONE card!, or equivalent) study card (both sides, hand-written or computer printed).

4. Format: short answer and multiple choice.

Studying for the Exam:1. Study your notes first (assigned reading in the text should provide additional information and explanation; use the study guide to the text and the assigned reading pages from the course syllabus to guide your study of the textbook material and your notes).2. Emphasis is on major concepts (when you see a section in your notes representing a significant portion of a lectureyour notes representing a significant portion of a lecture period, ask yourself, “can I describe this concept or process?”).3. Try to develop understanding and visualization, not memorization (example: transfer of energy – radiation, conduction, convection; see Figure in text or Intro PPTs).4. Read questions carefully; be sure you know what is being asked before starting to answer.5. Prepare your study card thoughtfully.

Energy transfer – radiation (radiating energy), conduction, convection

Fig. 11.17 Text

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Note very significant correlation with “taking notes” in class!

Taking notes in class works!

Modified (in red, except for red line on the graph) from Perry Samson, U. of Mich. (https://er.educause.edu/articles/2015/8/promoting-engagement-in-larger-classes)

Attendance shows no correlation!

Comparison plot of student study habits and exam scores

Student Behavior

Incoming GPA

>3.5 3.0–3.5 <3.0

Attendance 100% 99% 95%Answered 100% 97% 82%

Looking more carefully at additional data on the students in the previous slide (Average Exam Scores vs. Incoming GPA), the table below shows that students with GPA > 3.5 were about 3 times as likely to have Noted Confusion (in their in-class notes), and 4 times as likely to have a substantial Volume of Notes as compared to students with GPA < 3.0!

From Perry Samson (except in red, above), U. of Mich. (From Table 1. in: https://er.educause.edu/articles/2015/8/promoting-engagement-in-larger-classes)

Answered Questions 100% 97% 82%Answered Questions Correctly

100% 88% 58%

Noted Confusion 100% 84% 33%

Volume of Notes 100% 59% 25%

Additional suggestions for study/learning (November, 2013): Recent psychology research and studies on learning have suggested a new approach for more effective study, learning and understanding. The method is called Retrieval Based Learning (RBL) and emphasizes practicing recall or retrieval of information rather than simple study techniques such as repeated reading of notes or textbook material. Of course the available notes (your own or instructor’s materialscourse, the available notes (your own or instructor’s materials provided or posted online) and assigned or optional reading (textbook or other materials) need to be studied first before retrieval is possible, but repeated reading, without practice in recall, is not as effective as RBL. (It also helps to focus on developing an understanding of concepts, not just memorizing a description. If you have a good understanding, you will be able to accurately and clearly describe the concept and evaluate and answer questions related to the concept.)

Some suggested strategies (summarized from: http://theelearningcoach.com/learning/retrieval-cues-and-learning/) for RBL (after completing at least one thorough reading of the material for an exam):1. Spend time practicing retrieval. Ask yourself questions about the material to test your recall without consulting available notes or textbook or other reading material.2. Practice in a “testing environment” – quiet, focused, timed –not while watching TV, listening to music, etc.3. Perform multiple “self-checks” and exercises such as asking yourself questions about the most important material in the subject area that will be covered on the exam. (A 3x5 “study card” can be a good prompt for the self-check.)4. Use group discussion (or study with one other person) to practice retrieval. Ask each other questions about the material.

More information on these strategies and Retrieval Based Learning (and references) can be found at: http://theelearningcoach.com/learning/retrieval-cues-and-learning/.

I highly recommend reading the short discussions of the process of retrieval and Retrieval Based Learning on this website The references to more detailed discussions andwebsite. The references to more detailed discussions and research results are also included there.

The silica (silicon-oxygen)tetrahedron, SiO2

Figure 1.22, text.

(Also, see sketch in Lecture Note Figures 1)

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Most rocks (including most of the Earth’s crust and mantle – over 82% of the volume of the Earth) are silicates

XSiO2 not always 2

where ‘X’ is K Na Al Fe Mg Ca or combinationwhere X is K, Na, Al, Fe, Mg, Ca, or combination.

Another common rock type in the sedimentary layer is Limestone

CaCO3 (no Si)

Silicate minerals,(Figure 1.23, text)



Non-Silicate minerals, Figure 1.30, text

Rock (granite): an aggregate of minerals(Figure 1.3, text)

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1 cm

1 cmquartz

hornblende

feldspar

Polished granite tile

~1 cmquartz

hornblende

feldspar

biotite

Rock Types: (remember the rock samples)

Igneous (from melt)● volcanic (cools rapidly on surface, fine grain)● plutonic (cools slowly in interior, coarse grain)

Sedimentary ● clastic or detrital (made up of fragments of mineral ( p ggrains and rocks; mudstone, sandstone, conglomerate)● chemical (precipitated; salt, limestone, gypsum)

Metamorphic ● deformed and re-crystallized by heat and pressure

(without melting) at depths of several km in Earth

IgneousVolcanic, fine grain, erupts on surface of Earth, cools rapidly (Figure 2.4, text)

Igneous, volcanic, fine grain(Figure 2.4, text)

Igneous Plutonic, coarse grain, cools slowly at depth (Figure 2.4, text)

Igneous, plutonic, coarse grain(Figure 2.14, text) Igneous, two grain sizes – cools at depth

to form larger crystals, then erupts

Sedimentary

Sandstone(Figure 2.20, text)

Mudstone or shale(Figure 2.18, text)

Conglomerate(Figure 2.20, text)

SedimentaryLimestone

CaCO3

Conglomerate(Figure 2.20, text)( g )

LimestoneOolitic

Limestone

Limestone Quarry

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Metamorphic

Gneiss, note banding/alignment, called “foliation”)

SchistMica

Garnet

The Rock Cycle(Figure 2.1, text)

Iron-Nickel Meteorite (representative of the material in the Earth’s core)

Earth’s Interior

StructureThe travel times of seismic waves through the Earth to different distances can only be matched by a model

P wave

matched by a model Earth that has layering as shown here (crust, mantle, outer core, inner core).(Figure 6.33, text)

For example, it takes about 20 minutes for seismic waves to travel straight throughthe Earth, an average velocity of 2*6371 km/20*60 s = 10.6 km/s

PP wave

PKP wave

P wave

(Figure 6.31, text)

PP wave

PKP wave

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Refraction of light by water

Similarly, seismic waves in the Earth are refracted and reflected at layer boundaries.Refraction

Reflection

Earth’s interior structure and seismic raypaths that are used to determine the Earth structure.

http://www.iris.edu/hq/files/programs/education_and_outreach/lessons_and_resources/images/ExplorEarthPoster.jpg

Seismograms (from the Jan. 16, 1994 M6.8 Northridge earthquake) for waves traveling through the Earth.

Shadow ZoneShadow Zone

From 3/11/2011 M9.0 N. Japan EQ

e (M

inut

es)

2

0

30

http://www.iris.edu/SpudService/Data/124332

Curved line for two reasons –spherical Earth, and faster seismic

Science for Planet Earth

Distance (Degrees, one degree = 111.19 km on surface)0 40 80 120 160

Tim

e0

1

0

velocity for rocks deeper within the Earth

Seismic Waves Program http://bingweb.binghamton.edu/~ajones/The Seismic Waves program: Uses speeded-up time views of wavefronts to illustrate wave propagation through the Earth. Note reflection, refraction and wave conversion at layer boundaries. Seismograms show arrivals of various phases (wave types and paths). Wave energy/propagation represented by wavefronts. Raypathsshow direction of travel of a specific point on the wavefront.

*Earthquake

Wavefront

Ray Path

Ray Path is perpendicularto wavefront

Seismograph

Cross SectionThrough Earth

Stations forSeismograms

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*Earthquake

Wavefront

Ray Path


Seismograph



Time T1

*Earthquake

Wavefront

Ray Path


Seismograph



Time T2

Earth’s interior structure and seismic raypaths that are used to determine the Earth structure.

http://www.iris.edu/hq/files/programs/education_and_outreach/lessons_and_resources/images/ExplorEarthPoster.jpg

September 15 http://www.intellicast.com/Storm/Hurricane/AtlanticSatellite.aspx?animate=true

September 16 http://www.intellicast.com/Storm/Hurricane/AtlanticSatellite.aspx?animate=true

September 15, 2018 http://www.intellicast.com/National/Radar/Current.aspx?location=USNC0121&animate=true

September 16, 2018 http://www.intellicast.com/National/Radar/Current.aspx?location=USNC0121&animate=true

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Waves spread out in circular pattern and the amplitudes become smaller with time (conservation of energy)

Earth’s Interior

Structure

(Figure 6.34, text)

Earth’s Interior

Structure

(Figure 6.34, text, also see Figure I.10, text)

Crust (high SiO2)

Mantle (low SiO2)

Core (Iron; liquidt lid

Earth’s Interior

Structure

(Figure 6.34, text)

outer core, solidinner core)

Crust – high % of SiO2 (granite, basalt, etc., density ~ 2.8 g/cm3)

Interior of the Earth:Earth is separated by chemical composition into spherical shells:

Mantle – low % of SiO2 (olivine-rich silicate rocks, density ~ 3.4-5.5 g/cm3)

Outer Core – liquid iron (density ~ 10-12 g/cm3)

Inner Core – solid iron (density

~ 13 g/cm3) (Figure 6.34, text)

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Earth’s InteriorStructure

(Figure 6.34, text)

Close-up of upper 600 km of Earth

Lithosphere (about 100 -200 km thick, includes crust and uppermost mantle)

Asthenosphere (beneath lithosphere)

T ~ 12 oC at surface

Lithosphere

Temperature in Earth’s Interior

( p )

T ~ 1300 oC in asthenosphere

T ~ 3700 oC at core/mantle boundary,(~2900 km depth)

T ~ 5000 oC at center of Earth,(6371 km depth)

600 km

p~100 km thick

Close-up of upper 600 km of Earth (Heat from original energy from accretion and radioactivity of Earth)

(Figure 6.34, text)

Olivine – an important silicate mineral (iron/magnesium silicate) in the )Earth’s mantle (the mantle is 82% of the planet by volume).



Earth Science, Lutgens and Tarbuck, 8th Edition, 2017

Intro section PPTs (through today) have been updated th PPT (i df f t) li (li k f thon the PPTs (in pdf format) online (link from the

course home page)

Handouts: Lecture Note Figures 1A , 1 and 2

Hw 1 - due Tu, 9/18, Hw 2 – due 9/27

Lecture Notes/PPTs for Intro section now online

Exam I is Tu, 9/25; will discus in class Th, 9/20: Exam I, studying for exam, Study Guide (online)

Y Dimensionless Speed versusStride length for walking and running animals

Use these points, on the line, to calculate the slope!

Ill t ti 1

dy2

Slope of a line (or best-fit line), information for Hw 2, etc.

To calculate slope, don’t just “count squares” –that ONLY works when the squares are one unitby one unit on each side slope = dy/dx. X

Illustration of dx and dy

1

dx

Graph from our discussion of how fast dinosaurs ran.

Compass direction: N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNWEquivalent Azimuth: 0 22.5 45 67.5 90 112.5 135 157.5 180 202.5 225 247.5 270 292.5 315 337.5

EAPS 10000 Homework 2 Information: Measuring directions with “points of a compass” and azimuth.

45o

Azimuth (similar to compass directions) is the angle in degrees measured clockwise f N th (0 360

315o

A Azimuth = 0o

90o

135o

180o

225o

270o

from North (0 or 360 degrees). For example, for the direction shown (bold arrow; and the angle shown by the dashed lines), the azimuth is 135o and the compass direction is SE.

Angle

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Interior of the Earth:

Earth is separated by chemical composition into spherical shells:

Crust – high % of SiO2 (granite, basalt, etc.)

Mantle – low % of SiO2 (olivine-rich silicate rocks)

Outer Core – liquid iron

Inner Core – solid iron (Figure 6.34, text)

Plate TectonicsEarth’s platesLithosphere and asthenospherePlate boundaries, motions and

interaction

Properties of Earth materials (rocks):

PHYSICAL –density, elasticity, mechanical (brittle/ductile)

CHEMICAL –chemical composition (% of different minerals)

CONDITIONS –temperature, pressure, time

Elasticity (spring, rubber band, rocks)

Elastic Materials(straight line)

ng

(D

efo

rmat

ion

) Weak elastic materials (easily deformed)

Weight (force)(if force is removed, material returns to its original shape)

Str

etch

in

Key words: elastic, brittle, ductile

Strong elastic materials, like most rocks (requires large force to deform)

Click on slide to start video

Illustration of elasticity of a rock – in this case two strips of granite tile securely clamped together at one end with a thin metal spacer between the strips at that end (left). The granite tile is very hard and rigid, but can be bent, although bending too much will cause it to break (as most rocks are brittle at low temperatures). Note in the video, that when the granite tile strips are squeezed together and then released, they return to their original position because the granite is elastic, although much stronger (higher coefficient of elasticity) than materials such as rubber bands, springs, plastic, and wood that can be bent or stretched easily. Video File: http://web.ics.purdue.edu/~braile/new/ElasticRebound.AVI

Earth’s Plates (lithosphere) continued:

Plate Boundaries –divergent, convergent, transform

Plate Motions – ~ 1 to 15 cm/yr The lithosphere is the crust and the

uppermost mantle (relatively cool, strong and brittle) – NOT just the crust!

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Earth’s Plates (lithosphere):

Dimensions –1000’s of km wide~100 km thick

Mechanical Properties –‘strong’, ‘brittle’ (cool) lithosphereabove ‘soft’, ‘ductile’ (hot) asthenosphere

Lithosphere, Plates (includes both crust and the uppermost part of the mantle):Cool, Elastic, Brittle, Strong, Rigid

Asthenosphere, part of the upper Mantlebeneath the lithosphereHot, Plastic, Ductile, Soft, Flows

This layering (the plates) is caused by temperature increasing with depth in the Earth. The base of the lithosphere (top of the asthenosphere) is about 1300 oC and averages about 100 km depth.

The hard boiled egg analogy to the Earth’s interior

Crust, Mantle and Core (chemical classification) or Lithosphere, Asthenosphere (and deeper

regions; mechanical classification)

The hard boiled egg analogy to Earth’s lithospheric plates

The Lithospheric Plates and Plate Boundaries

(Sliding a piece of the shell causes divergence, convergence or

translation at the boundaries)

Lithosphere

Mantle part

Crust

Crust-Mantle boundary

Earth’s Interior

Structure

(Figures I.10, 5.9, text)

Notice that the Lithosphere consists of the crust and part of the upper mantle. Also, the oceanic crust is different than the continental crust.

Mantle part of Lithosphere Asthenosphere

Lithosphere (about70 -150 km thick, includes crust and uppermost mantle)

Asthenosphere(layer beneath Lithosphere ( ylithosphere)

600 km

p~100 km thick

Close-up of upper 600 km of Earth

(Figure 6.34, text)

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Earth’s Tectonic Plates

http://geology.er.usgs.gov/eastern/plates.html

The North American and surrounding plates. Note that the plate boundaries are not always continental boundaries.

Earth’s Plates (lithosphere) & Plate boundariessee Fig. 5.10, text

Earth’s Plates

Figure 5.11, L&T, 2011

C t

The three typesof plate boundaries…

(Figure 5.10, text)

Divergent

Basaltic (generally non-explosive) volcanism (from melting of normal mantle)

Convergent

Transform(horizontal slip)

Silicic (explosive) volcanism (cone-shaped Rhyolite/Andesite volcanoes, from melting of subducted crust and sediments)

Plate Tectonics

Divergent boundaryMid-ocean ridges,Figure 5.11, text

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Plate Tectonics

Divergent boundary,Continental rift and separation,Figure 5.13, textFigure 5.13, text

Plate Tectonics

Divergent boundary,Continental rift and separation in

i E tprogress in East Africa and Red Sea,Figure 5.14, text

Plate Tectonics

Convergent boundary,‘subduction’,Figure 5.15,text

Oceanic plate-continental plate collision

Oceanic plate-oceanic plate collision (Island Arc)

Continental plate-continental plate collision

Silicic (explosive) volcanism (cone-shaped Rhyolite/Andesite volcanoes, from melting of subducted crust and sediments)

Trench

Plate Tectonics, Convergent boundary,ocean plate collision with a continental plate; like west coast of South America, Figure 5.15, text

Rocks deformed (folded and faulted [blue lines on photo]) by local compressional forces.

Plate Tectonics

Convergent boundary,Continent-

ti tcontinent collisionFigure 5.18, text

Collision of India plate with Asia over past 70 million years

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Plate Tectonics

Transform boundary;offsets of mid-oceanridges,Figure 5.19, textFigure 5.19, text

Plate Tectonics

Transform boundary;(also called a strike-slip fault)San Andreas fault,Figure 5.21, text

Fault

Offset of stream valley by recent movement along fault

Relative motion

Plate Tectonics in the Pacific Northwest

Plate Tectonics in the Pacific Northwest

Three types of plate boundaries;Figure 5.20, text

San Andreas fault – a transform (horizontal slip) plate boundary)

Plate Tectonics

World view of plates; Asia and western Pacific; example of plateexample of plate boundaryFigure 5.10, text

Divergent Boundary

Plate Tectonics

World view of plates; ~westernhemisphere; examples of plateexamples of plate boundariesFigure 5.10, text

Convergent Boundary Transform Boundary

Please view the Pearson animations related to plate tectonicsOpen the link below (you can copy the link from below and paste it into your web browser) and scroll down to the section: ONLINE ANIMATIONS FROM PEARSON. From the links displayed in that section, select the animations below (first 4 are the most important) and view them. To view, open the selected animation, click on the bold white arrow to start animation. The animations have sound (and also closed captioning) that provides explanations of the animations. Most animations are 1- 3 minutes long. The “moving part” of the animation sometimes starts 30-60 s after starting the

i ti U th d bl t th l i ht t t F ll S Othanimation. Use the double arrow at the lower right to get Full Screen. Other animations are also available on the page.

1. Seafloor Spreading and Plate Tectonics, 2. Transform Faults, 3. India Collision with Asia, 4. Pangea Breakup,5. Motions at Plate Boundaries, 6. Plate Boundary Features

Seafloor Spreading and Plate Tectonic animation:

http://subduction.rocks/Animations%20Index.htm

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Transform faults

Mid-ocean ridge

African Plate

Fracture zone

Fracture zone

Transform faults in the Atlantic ocean basin. Map image from This Dynamic Planet map (http://pubs.usgs.gov/imap/2800/).

Transform faults. Note that the earthquakes (black dots) are primarily on the active part of the transform fault where the two sides of the fault (in the lithosphere) are sliding past each other and offsetting the mid-ocean ridge (red lines).

g

Cross section through Mid-ocean ridge

Cross sectionlocation

Transform faults in the Atlantic ocean basin. Image from This Dynamic Planet map (http://pubs.usgs.gov/imap/2800/).

Transform fault

Mid-ocean ridge

Fracture zoneFracture zone

Depth in meters

2000

4000

Break up of Pangaea

http://www.odsn.de/odsn/services/paleomap/animation.html Deep sea drilling sites where ocean crust ages are determined are red dots. Also:http://earthguide.ucsd.edu/eoc/teachers/t_tectonics/p_plate_reconstruction_blakey.html

PLATES 2009 Atlas of

Plate Reconstructions(750 Ma to Present Day)

By

Show UTA plate reconstruction ppt

2009, University of Texas Institute for Geophysics, May 4, 2009

By L.A. Lawver, I.W.D. Dalziel,

I.O. Norton and L.M. Gahaganhttp://www-

udc.ig.utexas.edu/external/plates/recons.htm#movies

Please reference as:Lawver, L.A., Dalziel, I.W.D., Norton, I.O., and Gahagan, L.M., 2009, The PLATES2009 Atlas of Plate Reconstructions (750 Ma to Present Day), PLATES Progress ReportNo. 325-0509, University of Texas Technical Report No. 196, 156 pp.

http://www-udc.ig.utexas.edu/external/plates/recons.htm

PDF of last 250 m.y. plate reconstruction available at:http://web.ics.purdue.edu/~braile/eas100/PLATES_Atlas.2009.Last.250.m.y.pdf

EAPS 10000 -001 Planet EarthProf. L. Braile

2271 HAMP, [email protected]

About every 4th or 5th person, please take a sheet of paper being passed out.

Exam I information and suggestions for study

Tuesday, Sept. 25, in class, Noon-1:15 p.m.

Continuation of Plate Tectonics:

Evidence for Plate tectonics

The Driving Mechanism for Plate Tectonics (What makes the plates move?)

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Composition of the Earth:

(How do we know what the Earth’s interior consists of?)

Quiz 3 – Cooperative Learning/Teamwork Exercise

1. Form groups of 4-5 students, elect a leader.2. Leader is responsible for:

a. Taking notes on blank paper; b. Be sure that all members of the group participate;g p p pc. Names of all students in group on paper; be sure to

print legibly!d. Hand in Notes (10 points per person) at end of class.

3. Questions for discussion: How do we know what the Earth’s interior consists of? What observations or evidence is there that allows us to infer the composition of the Earth’s interior? Discuss and list 4 observations in your notes.

Composition of the Earth:(How do we know what the Earth’s interior consists of?)

1. Composition (chemistry) of meteorites (iron; ratios of elements).

2. Average density of Earth ~5.2 g/cm3

(http://www.enchantedlearning.com/subjects/astronomy/planets/earth/Mass.shtml, http://www.scientificamerican.com/article.cfm?id=how-do-scientists-measure,

http://www.astronomyforbeginners.com/astronomy/howknow.php#massearth), the density of the crust and of surface rocks is much less, <~2.8 g/cm3, so the interior must be more dense.

3. Seismic wave velocity – compare observations of travel times through the Earth with laboratory measurements of different rock types; shows that rocks at depth have much higher velocities.

4. Mantle rock samples (xenoliths, brought to surface by volcanoes).

5. Exposures at the surface of deep crust and upper mantle rocks produced by geological processes.

6. Surface rocks (representative of Earth’s crust and for comparisonwith composition and properties [velocity, etc.] of deep Earth.

Evidence for Plate Tectonics:

1. Fit of the continents

2. Rock and fossil correlation across plate boundaries

(brief list; see also p. 143- 147; p. 158 – 164, text)

boundaries

3. Ocean age and depth increase away from mid-ocean ridges

4. Deep sea trenches at convergent boundaries

Evidence for Plate Tectonics (continued):

5. Earthquakes and volcanoes along plate boundaries

(brief list; see also p. 143- 147; p. 158 – 164, text)

6. Deep earthquakes in subducted lithospheric slab at convergent boundaries

7. Magnetic stripes parallel to mid-ocean ridges (divergent boundaries)

8. Hotspot tracks

1.Fit of the continents

Figure 5.3, text

1.Fit of the continents;continental drift

Figure 5.2, text

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1.Fit of the continents;

continental drift

Fi 5 29Figure 5.29, text

Break up of Pangaea

http://www.odsn.de/odsn/services/paleomap/animation.html Deep sea drilling sites where ocean crust ages are determined are red dots. Also:http://earthguide.ucsd.edu/eoc/teachers/t_tectonics/p_plate_reconstruction_blakey.html

2. Rock and fossil correlation across plate boundaries, Figure 5.4, text


Another image - Mesosaurus


also see Figure 5.4, text


Figure 5.6, text

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also see Figure 5.6, text

2. Rock and fossil correlation across plate boundaries (early Paleozoic glaciation) Figure 5.7, text

2. Rock and fossil correlation across plate boundaries (early Paleozoic glaciation) Figure 5.7, text

3. Ocean age and depth increase away from mid-ocean ridges

http://gdcinfo.agg.nrcan.gc.ca/app/agemap_e.html

3. Ocean age and depth increase away from mid-ocean ridges, Figure 9.15, text 4. Deep sea trenches at convergent

boundaries, Figure 5.13, text

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4. Deep sea trenches at convergent boundaries, (close-ups) and subduction model, Figure 5.13, text

5. Earthquakes and volcanoes along plate boundaries, Figure 6.16, text


http://www.minerals.si.edu/tdpmap/ (Interactive Map)






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Basaltic volcanism at mid-ocean ridges (melting of normal mantle)


Silicic (explosive, cone-shaped volcanoes) volcanism at convergent boundaries (melting of oceanic lithosphere and continental crust)


6. Deep

Figure 7.30

6. Deep earthquakes in subducted lithospheric slab at convergent boundaries (also see Fig. 6.16, text)

Earthquakes - Samoa Islands region 1960-2008 – Cross section diagram

Distance (km)

Dep

th (

km)

7. Magnetic stripes parallel to mid-ocean ridges (divergent b d i )boundaries). Due to reversals of the Earth’s magnetic field.Figure 5.28, text

7. Magnetic stripes parallel to mid-ocean ridges (divergent boundaries). Due to reversals of the Earth’s magnetic field.Figure 5.27, text

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7. Magnetic stripes parallel to mid-ocean ridges (divergent boundaries). Due to reversals of the Earth’s magnetic field.Figure 5.26, text

8. Hotspot tracks (like Hawaii)

Figure 5.22, text (age in millions of

years)

(like Hawaii) show direction of motion of the lithosphere over a hotspot (by age of volcanic activity)


http://pubs.usgs.gov/imap/2800/


Driving Mechanism for PLATE TECTONICS:(What makes the plates move?)

Heat from original heating of Earth and decay of radioactive elements (uranium, thorium, potassium, etc.) in Earth’s interior is ultimate cause; viable theories for the driving mechanism are:

(see also p. 164 – 167, text)

1. “Ridge Push” (seafloor spreading) – rising hot material at ridge crests (new lithosphere) pushesplates apart

2. “Slab Pull” – dense, older oceanic lithosphere in subducted slab sinks

3.Convection currents in hot, solid but soft, partially molten mantle (asthenosphere) convects

“Ridge Push” (sea floor spreading) and “Slab Pull” mechanisms

(also see Figure 5.27, text)

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“Convection Current” mechanism(also see Figure 5.28, text)

“Ridge Push” and “Slab Pull” mechanismsFigure 5.31, text

“Convection Current” mechanismsFigure 5.32, text

End of Material covered in Exam I

Continue with Earthquakes(below)( )

M6.3 South Island New Zealand Earthquake, Feb. 21, 2011

Some views of earthquake damage…


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M6.3 South Island New Zealand Earthquake, Feb. 21, 2011 M6.3 South Island New Zealand Earthquake, Feb. 21, 2011


More than 5000 people have died after a powerful 7.8 magnitude earthquake hit Nepal less than 50 miles (80 km) from the capital Kathmandu, with aftershocks continuing. (CNN.com, April 24, 2015)

More than 5000 people died after a powerful 7.8 magnitude earthquake hit Nepal less than 50 miles (80 km) from the capital Kathmandu, with aftershocks continuing. (CNN.com, April 24, 2015)

More than 5000 people died after a powerful 7.8 magnitude earthquake hit Nepal less than 50 miles (80 km) from the capital Kathmandu, with aftershocks continuing. (Yahoo.com, April 26, 2015)

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We also observed the importance of location of an earthquake (close or far from cities, etc.) and of quality of construction (related to resistance to earthquake shaking) in the M6.2, August 24, 2016, earthquake in Italy.

Fault scarp from 1915 earthquake in Nevada. Movement was down to the right continuing the formation of valley (“basin”) and ridge (“range”) topography of the Basin and Range

i th t

The fault line (scarp) in Pleasant Valley following its 1915 earthquake, its magnitude of 6.8 was the most power earthquake in Nevada's history (https://www.unr.edu/nevada-today/news/2017/great-nevada-shakeout-2017-x82075).

province that covers much of Utah and Nevada and adjacent areas.

Scarp

Earthquakes:Causes of earthquakes (elastic rebound

d b l i )caused by plate tectonics)Seismic wavesEarthquake locations and statisticsEarthquake hazards, effects, damage

EARTHQUAKES:

Sudden sliding (relative motion on two sides of fault plane) of fault which releases stored elastic energy (strain) and generates seismic waves (vibrations, ground motion) which propagate outward from the fault planepropagate outward from the fault plane

Occur mostly in narrow zones related to plate boundaries. Faults (and, therefore, earthquakes) are caused by plate motions (stored strain)

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Why care about earthquakes?

For perspective, food poisoning accounts for about 3000 fatalities per year in the U.S. (2011 estimate; http://www.cdc.gov/Features/dsFoodborneEstimates/); also, overdoses from prescription drugs kill about 45 people per day (CDC.gov).

Fatality statistics/probability of accidental deaths per year for common activities, and comparison with U.S. Earthquake fatalities

(see sources in Sunset magazine, June, 2012)Note mitigation – effect of wearing a helmet – about a factor of 5!

U S E th k : 9 b bilit i b t U.S. Earthquakes: average ~9 per year, so probability is about 1/30,000,000 (of course this is an average and will also depend on whether you live in N. Dakota or near the San Andreas fault!)Other relevant statistics: U.S. deaths from underage alcohol consumption total 4300 per year (http://www.cdc.gov/alcohol/fact-sheets/underage-drinking.htm). 2015 Opioid deaths: 20,101 overdose deaths related to prescription pain relievers, and 12,990 overdose deaths related to heroin. (https://www.asam.org/docs/default-source/advocacy/opioid-addiction-disease-facts-figures.pdf)

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An Example of Risk and Risk Reduction – Motor Vehicle Fatalities in the United States (Wikipedia)

Year Fatalities Population Fatalities/ Fatalities/(millions) 100,000 people billion miles driven

1972* 54,589* 20926.0~44198051,09122722.5~341990 44 599 250 17 9 ~21199044,59925017.9~21200041,94528214.9~18201032,88530910.7~12* Historicalhigh

Since the 1960’s, annual vehicle fatalities in the U.S. per billion miles driven have decreased from about 55 to about 11. That’s a factor of 5 decrease, equivalent to an 80% decrease! In risk analysis and conservation we are often pleased to get 5 to 10% reductions, so this is huge. Much of the reduction is due to government regulations that have included seat belt use, safer vehicles, air bags, and safer roads.

Year Fatalities Population Fatalities/ Fatalities/(millions) 100,000 people billion miles driven

1972* 54,58920926.0 ~44198051,09122722.5~34199044,59925017.9~21200041,94528214.9~18201032,88530910.7** ~12

Some of the reasons for the drop in fatalities are: 1. Safer vehicles, 2. Increased seatbelt usage, 3. Decrease in number of drivers under the influence, 4. More focus on the road, and, 5. Drivers driving defensively. ** That’s about one death per 10,000 people per year.

It is estimated that 85 percent of all drivers now use their seatbelts. Alcohol-related traffic deaths declined by 7.4 percent between 2008 and 2009. These accidents are the leading types of fatal traffic accidents.

The NHTSA continues to study the safety of vehicles being produced by vehicle manufacturers. (http://www.atlanta-insurance-claims-resource.com/traffic-accident-statistics.html)

Standard

Measuring Elasticity of a Spring Added Mass (g)

Spring Extension

(cm)*(adding masses)

Spring Extension

(cm)*(removing

masses)

Elasticity – a property of materials that resultsin wave propagation and earthquakes.

Wood

PV

C P

ipe

Mass

SpringLength of Spring

0 0.0 0.3

100 3.7 3.6

200 7.7 7.5

300 11.4 11.4

400 15.3 15.1

* Difference in length of spring before and after adding mass.

Some useful seismic waves terminologyWave types – P (primary, compressional, body wave), S

(secondary, shear, body wave), Rayleigh (R, surface wave), Love (L, surface wave)

Material properties – elastic, brittle, ductile

Seis … – seismic, seismometer, seismograph, seismogram, seismology, seismologist

Ground motion – displacement (in cm or m), velocity (in km/s or m/s or cm/s for particle velocity) acceleration (in cm/s2 orm/s, or cm/s for particle velocity), acceleration (in cm/s or m/s2, or %g [percent of the acceleration of gravity on Earth which is 9.807 m/s2]), frequency (Hz or cycles per second), wavelength (m or km), period (seconds or minutes)

Deformation – Stress, Strain (Hooke’s Law – stress is proportional to strain); strain is relative change (unit-less) in shape or size due to applied force; stress is force per unit area associated with strain(http://physics.bgsu.edu/~stoner/p201/shm/sld002.htm)

Seismographs – mass, spring, magnet and coil, damping, simple harmonic motion

Seismic Waves* measured in units of:

Displacement (m)

Velocity (m/s)

A CB

To better understand these different measures related to motion, imagine driving your car a short distance from a stopped position at point A to point C, stopping at point C. Note that you would increase your

l it d thtude

Time

Acceleration (m/s2)

* For example, at a point on a fault plane during EQ fault rupture.

velocity and then decrease velocitybefore stopping at C. The velocity would be a maximum at about the half-way point, B. The

acceleration would be greatest between A and B, zero at B, and the deceleration (negative acceleration) would be greatest between B and C. The displacement curve records the distance traveled versus time.

Am

plit

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We may be most familiar with acceleration from riding in a roller coaster. Near the bottom of the hill (below left), we feel an increased downward force (equivalent to increased acceleration of gravity). Near the top of the hill, we may feel weightless or even lift off the seat, being held in the seat by the car’s restraining bar.

The Accelerometer phone app (there are many, this one is Accelerometer Analyzer) shows horizontal (left-right, then up-down) acceleration, then vertical (perpendicular to the screen) acceleration signals. http://web.ics.purdue.edu/~braile/new/Accelerometer.avi

Why care about earthquakes?

10

12

14

16

gin

al l

en

gth

, cm

)

Elasticity of a Spring

Adding mass:

Removing mass:

0 50 100 150 200 250 300 350 4000

2

4

6

8

Added Mass (grams)

Str

etc

hin

g (

len

gth

- o

ri

1. Deformation (stretching) isproportional to applied force (mass).

2. Spring returns to its original shape(length) when force is removed.

Elasticity (spring, rubber band, rocks)

Elastic Materials(straight line)

ng

(D

efo

rmat

ion

) Weak elastic materials (easily deformed)

Weight (force)(if force is removed, material returns to its original shape)

Str

etch

in

Key words: elastic, brittle, ductile

Strong elastic materials, like most rocks (requires large force to deform)

Click on slide to start video

Illustration of elasticity of a rock – in this case two strips of granite tile securely clamped together at one end with a thin metal spacer between the strips at that end (left). The granite tile is very hard and rigid, but can be bent, although bending too much will cause it to break (as most rocks are brittle at low temperatures). Note in the video, that when the granite tile strips are squeezed together and then released, they return to their original position because the granite is elastic, although much stronger (higher coefficient of elasticity) than materials such as rubber bands, springs, plastic, and wood that can be bent or stretched easily. Video File: http://web.ics.purdue.edu/~braile/new/ElasticRebound.avi

Elastic Rebound TheoryDiscovered by analysis of the fault motion and

deformation before and during the 1906 San Francisco earthquake (before plate tectonics theory).

Theory is consistent with plate tectonics, in fact, it explains how the slow motions of the plates can result in the rapid slip along a fault to produce an earthquake.

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Elastic Rebound TheoryDiscovered by analysis of the fault motion and

deformation before and during the 1906 San Francisco earthquake (before plate tectonics theory).

Theory is consistent with plate tectonics, in fact, it explains how the slow motions of the plates can result in the rapid slip along a fault to produce an earthquake.

Elastic Rebound(also see Fig. 6.5,text)

Slow build-up of deformation (strain, bending) in thebending) in the rocks by plate motions. Strain (energy) is released (restoring force in elasticity) suddenly as fault slips (ruptures; earthquake!).

Foam model illustrating elastic rebound concept – imagine looking down on the San Andreas fault. Over a long period of time, the plates (Pacific plate on left and N. American plate on right); move at about 4 cm/yr (relative motion). View the left and right edges of the foam as about 100 km away from the fault. Note the deformation of the plate, sudden slip (elastic rebound), and both small and large ruptures (earthquakes).Video File: http://web.ics.purdue.edu/~braile/new/FoamRebound.aviAlso see: http://web.ics.purdue.edu/~braile/edumod/foammod/foammod.htm

Elastic Rebound

Slow build-up of deformation (strain, bending) in the rocks by plate motions. Strainmotions. Strain (energy) is released (restoring force in elasticity) suddenly as fault slips (ruptures; earthquake).

Figure 6.5 text.

Elastic Rebound

Slow build-up of deformation (strain, bending) in the rocks by plate motions Strainmotions. Strain (energy) is released (restoring force in elasticity) suddenly as fault slips (ruptures; earthquake!).

Elastic ReboundSlow build-up of deformation (strain, bending) in the rocks by plate motions. Strain (energy) is(energy) is released (restoring force in elasticity) suddenly as fault slips (ruptures; earthquake!).

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The 1906 San Francisco Earthquake (M~7.8) ~3 m right lateral offset on the San Andreas fault

Dixie Valley – Fairview Peak Earthquakes (1954)Fault Scarp

Exploring Planet Earth

http://earthquake.usgs.gov/regional/states/events/1954_12_16.php

North AmericanPlate

Also see Figure 6.6, text

PacificPlate

North AmericanPlate

PacificPlatePlate

Transform or horizontal slip fault

Plate Tectonics

Transform boundary;(also called a strike-slip fault)San Andreas fault,Figure 5.24, text

Fault

Offset of stream valley by recent movement along fault

Relative motion

North AmericanPlate

The San Andreas fault system is much more complicated than the image shown

PacificPlate

the image shown here. (Also see Figure 6.6, text)

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The San Andreas fault system is much more complicated than the image shown on the previous slide. Thirty days small magnitude earthquake activity, San Bernardino and Palm Springs area. (from temblor.net Feb. 10, 2017)

10 km

The San Andreas fault system is much more complicated than the image shown on the earlier slide. Thirty days of earthquake activity, Los Angeles area. (from temblor.net Feb. 10, 2017)

20 km

The San Andreas fault system is much more complicated than the image shown on the earlier slide. Thirty days of earthquake activity, San Jose area. (from temblor.net Feb. 16, 2017)

Earthquakes (orange dots) and faults (thin black lines) in the San Francisco Bay area.

EAPS 100 – Planet EarthProf. L. Braile2271 CIVL, [email protected]

Earthquakes:Causes of earthquakes (elastic rebound

d b l i )caused by plate tectonics)Seismic wavesEarthquake locations and statisticsEarthquake hazards, effects, damage

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San Andreas faultNotice correlation of

Hayward fault

Notice correlation of faults with topographic features (ridges and valleys). Although the fault motion is primarily horizontal (strike-slip), there is also some vertical displacement.

Hayward fault at the U. C. Berkeley football stadium

Earthquake Focus and Epicenter Figure 6.2, text

Blind Thrust Fault Earthquake Rupture Animation (Northridge, 1994)Brad Aagaard, USGS

http://pasadena.wr.usgs.gov/office/baagaard/research/animations/animations.htmlThe fault rupture will be visible in the animation. Displacements (magnified 3000

times) will be visible by the movement of the mesh from the model. The amplitude of motions and seismic waves is color coded according to ground velocity.

Note the rupture along the fault over time from the deepest extent of the fault.

In the following slide (animation), we see the displacement(exaggerated so it is visible at this

l ) i th t f th

http://web.ics.purdue.edu/~braile/new/AagaardBlindThrustAnimation.ppt , Also: http://web.ics.purdue.edu/~braile/edumod/tsunami/BlindThrustSlice.gif

scale) in the movement of the mesh that was used for the computer program calculations. The color code indicates the particle velocity amplitudes (in m/s) of the seismic waves that are generated by the fault rupture.

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Blind Thrust Fault Earthquake Rupture Animation – Brad Aagaard, USGShttp://profile.usgs.gov/baagaard

The fault rupture will be visible in the animation. Displacements (magnified 3000 times) will be visible by the movement of the mesh from the model. The amplitude

of seismic waves is color coded according to ground velocity.

http://pasadena.wr.usgs.gov/office/baagaard/research/animations/animations.html

Note: Maximum ground motion (displacement and velocity) is located in the area above the fault (waves and rupture propagate upwards) and continues to propagate to larger distances.

http://pasadena.wr.usgs.gov/office/baagaard/research/animations/animations.html

Note: Rupture motion along fault – upper surface moves up and to left, lower surface moves down and to the right

Magnitude of earthquake is controlled by fault length that ruptures (data for diagram generated using Seismic/Eruption program)

1000

10000

km

)

Magnitude versus fault length (determined from aftershock zonelength) for various earthquakes (Alaska

Alaska, 1964

Sumatra, 2004

Magnitude versus fault length

10

100

6 7 8 9 10

Magnitude

Fa

ult

Le

ng

th ( earthquakes (Alaska,

1964; Sumatra, 2004; Denali, 2002; Landers, 1992; Loma Prieta, 1989; Northridge, 1994, etc.). Results were quickly obtained using Seismic/Eruption views.

Denali, 2002

Landers, 1992

Northridge, 1994

Loma Prieta, 1989

Earthquakes generate P, S and Surface waves (different velocity of propagation and different vibration pattern for the three wave types).

Seismic waves (P, S, Rayleigh Love) can beRayleigh, Love) can be

demonstrated using the slinky.

Wave animations

Animation courtesy of Dr Dan Russell Kettering UniversityAnimation courtesy of Dr. Dan Russell, Kettering University

http://www.kettering.edu/~drussell/demos.html

Seismic Wave animations(Developed by L. Braile)

http://www.eas.purdue.edu/~braile/edumod/waves/WaveDemo.htm

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Dan Russell animations – The people wave

Animation courtesy of Dr. Dan Russell, Kettering University


Dan Russell animations – A wave pulse (P-wave)



Dan Russell animations –Transverse wave (S-wave)



Dan Russell animations – Rayleigh wave



http://www.eas.purdue.edu/~braile/edumod/waves/WaveDemo.htm

Compressional Wave (P-Wave) Animation

Deformation propagates. Particle motion consists of alternatingcompression and dilation. Particle motion is parallel to the direction of propagation (longitudinal). Material returns to its original shape after wave passes.

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Shear Wave (S-Wave) Animation

Deformation propagates. Particle motion consists of alternating transverse motion. Particle motion is perpendicular to the direction of propagation (transverse). Transverse particle motion shown here is vertical but can be in any direction. However, Earth’s layers tend to cause mostly vertical (SV; in the vertical plane) or horizontal (SH) shear motions. Material returns to its original shape after wave passes.

Rayleigh Wave (R-Wave) Animation

Deformation propagates. Particle motion consists of elliptical motions (generally retrograde elliptical) in the vertical plane and parallel to the direction of propagation. Amplitude decreases with depth. Material returns to its original shape after wave passes.

Love Wave (L-Wave) Animation

Deformation propagates. Particle motion consists of alternating transverse motions. Particle motion is horizontal and perpendicular to the direction of propagation (transverse). To aid in seeing that the particle motion is purely horizontal, focus on the Y axis (red line) as the wave propagates through it. Amplitude decreases with depth. Material returns to its original shape after wave passes.

Slinky and Elastic Rebound Demos

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41

Waves spread out in circular pattern and the amplitudes become smaller with time (conservation of energy)

Seismogram for a distant earthquake

P-wave S-wave

Surface waves

Time

Firstarrival

WLIN AS-1 Seismograph 24-hr Record Feb. 27-28, 2011 – M4.7 Arkansas Earthquake

WLIN 24-hr Record Updated Every 10 minutes – Online at:http://www.iris.edu/amaseis/schools/as1imgs/WLIN.png

Epicenter

WLIN AS-1 Seismogram – Feb. 28, 2011 M4.7 Arkansas Earthquake

P-waveS-wave

Lg (crustal guided, ~1.5 s period) wave

Earthquake: 35.265°N, 92.344°W, 05:00:50 GMT, Feb. 28, 2011, Epicenter to WLIN Distance = 7.09 degrees (788 km)

Where do earthquakes occur?

We’ll look at the IRIS Seismic Monitor to see an online map of recent earthquakes (updated every 10 minutes; www.iris.edu)

and, the free Windows software Seismic/Eruption to i lti l th k ti it d thview multiple earthquake activity maps and other

diagrams that can be used to study earthquake and volcanic eruption activity globally or locally

http://bingweb.binghamton.edu/~ajones/

Another very useful earthquake plotting and analysis tool is the IRIS Earthquake Browser: http://ds.iris.edu/ieb/

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http://ds.iris.edu/seismon/?http://uxblog.idvsolutions.com/2012/06/earthquakes-since-1898.html

WLIN AS-1 Seismograph 24-hour screen display for August 15-16, 2007 Earthquakes and topography. Intermediate and deep focus

earthquakes in subducted slabs along convergent margins. Convergent margins can have “megathrust” earthquakes that produce tsunamis.

Note shallow EQs along mid ocean ridges (MOR), rifts, and transform faults

Note shallow to deep EQs at subduction zones

MOR

Rift

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Seismic/Eruption includes up-to-date earthquake and volcanic eruption catalogs and allows the user to display earthquake and volcanic eruption activity in “speeded up real time” on global, regional or local maps that also show the topography of

the area in a shaded relief map image. Seismic/Eruption is an interactive program that

Viewing Earthquake Activity

includes a number of tools that allow the user to analyze earthquake and volcanic eruption data and produce effective displays to illustrate seismicity and volcano patterns.

http://bingweb.binghamton.edu/~ajones/http://web.ics.purdue.edu/~braile/edumod/svintro/svintro.htm

Creating a cross-section view (upper left to lower right in map view to the left) of earthquake locations with Seismic/Eruption – Kuril and Kamchatka area

NW

Map View (dots for shallow EQs are red, deepest EQs yellow)

Cross-sectionView

Shows northwest-dipping, subducted lithospheric slab

NW

The 1906 San Francisco Earthquake (M~7.8) San Andreas fault at Earthquake park near Tomales Bay

(road to Point Reyes)http://www.seed.slb.com/en/scictr/watch/seismology/pt_reyes.htm

1906Today

http://earthquake.usgs.gov/regional/nca/1906/18april/index.php

http://earthquake.usgs.gov/regional/nca/1906/18april/images/sf06.city.html

San AndreasFault

Note offset stream channels

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San Andreas Fault – A Right-Lateral Strike-Slip FaultWhat is the relative motion?Why is it called right-lateral?

Orange Grove and San Andreas FaultAlso see Figure 6.4, text

The 1906 San Francisco Earthquake (M~7.8) San Francisco after the Earthquake and fire.

From National Geographic Probability of Earthquakes in California (http://pubs.usgs.gov/fs/2008/3027/fs2008-3027.pdf)

Earthquake Magnitude and Intensity:

MAGNITUDE:

--Measure of the ENERGY released in the earthquake.

--Logarithmic scale -- M = 6 is ten times greater vibration than M = 5 (at the same distance).

-- no longer “Richter” magnitude! (just Magnitude or M)

-- Not a 1 to 10 scale. Microearthquakes may have negative magnitude (but not negative energy); largest observed

it d 9 5 b bl bmagnitude 9.5, probably because of finite strength of rocks.

INTENSITY

-- I to XII (Roman numerals) scale, measure strength of ground vibration at a location.

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I. Instrumental Not felt by many people unless in favorable conditions.

II. FeebleFelt only by a few people at best, especially on the upper floors of buildings. Delicately suspended objects may swing.

III. Slight

Felt quite noticeably by people indoors, especially on the upper floors of buildings. Many do not recognize it as an earthquake. Standing motor cars may rock slightly. Vibration similar to the passing of a truck. Duration estimated.Felt indoors by many people, outdoors by few people d i th d At i ht k d Di h

Modified Mercalli Intensity Scale

IV. Moderateduring the day. At night, some awakened. Dishes, windows, doors disturbed; walls make cracking sound. Sensation like heavy truck striking building. Standing motor cars rock noticeably. Dishes and windows rattle alarmingly.

V. Rather Strong

Felt outside by most, may not be felt by some outside in non-favorable conditions. Dishes and windows may break and large bells will ring. Vibrations like large train passing close to house.

VI. Strong

Felt by all; many frightened and run outdoors, walk unsteadily. Windows, dishes, glassware broken; books fall off shelves; some heavy furniture moved or overturned; a few instances of fallen plaster. Damage slight.

VII. Very Strong

Difficult to stand; furniture broken; damage negligible in building of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken. Noticed by people driving motor cars.

VIII. Destructive

Damage slight in specially designed structures; considerable in ordinary substantial buildings with partial collapse. Damage great in poorly built structures. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture moved.General panic; damage considerable in specially designed structures well designed frame structures thrown out of

IX. Ruinousstructures, well designed frame structures thrown out of plumb. Damage great in substantial buildings, with partial collapse. Buildings shifted off foundations.

X. DisastrousSome well built wooden structures destroyed; most masonry and frame structures destroyed with foundation. Rails bent.

XI. Very DisastrousFew, if any masonry structures remain standing. Bridges destroyed. Rails bent greatly.

XII. Catastrophic

Total damage - Almost everything is destroyed. Lines of sight and level distorted. Objects thrown into the air. The ground moves in waves or ripples. Large amounts of rock may move position.

Effects of Magnitudeand Distance

Data from: http://earthquake.usgs.gov/earthquakes/eqarchives/year/eqstats.php

How many M6+ earthquakes do we expect each year worldwide? How

M8+?many M8+?~150

Because S-waves travel slower than P-waves and the difference between the S- and P-wave arrival times (the S minus P time) is proportional totime) is proportional to distance, the S minus P time for an earthquake can be used to determine the distance from the station to the earthquake. Figure 6.14, text.

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S minus P times and calculated distances from 3 stations can be used to “triangulate” and determine the location of the epicenter. Figure 6.15, text.

Seismic wave amplitudes decrease with distance.

Seismogram plotted at same scale

The S and Surface wave arrivals are usually larger than the P waves and are therefore responsible for more damage.

Up Motion

N-S Motion

The horizontal directions of ground shaking are often significantly larger than the verticaln

= 9

80 c

m/s

/s

E-W Motion

than the vertical direction due to the motion of shear and surface waves. Also note duration of strong shaking.

Accelerograms from ~7.3 km from Northridge epicenter

1 g

of a

ccel

erat

ion

Liquefaction (where the solid ground takes on liquid qualities due to high fluid pressure, usually in saturated sand and earthquake vibration) causes distortion of buildings and damage to buried cables, water and sewage pipes. Sand blows are characteristic evidence that liquefaction has occurred.

Liquefaction occurs (and sand blows are formed) when the soft sandy soil

Sand blow created during the M7.0 New Zealand

Earthquake

New Zealand Herald-Photo / Georgia Galloway

when the soft, sandy soil shakes forcing liquefied sand to the surface causing heavy roads or whatever is on the surface to sink

USGS

Bay area shaking amplification (red is greatest amplification) and population density (right, 1000’s of people per sq. km) maps

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EAPS 10000-001 – Planet EarthProf. L. Braile2271 HAMP (CIVL), [email protected]

Hw 3 papers, due Oct. 23

Today: Completion of Earthquakes, begin Volcanoes

8th Edition, 2017

Exam I grading is almost finished, I will send an email to all when scores are posted, with info.

Exam II is Thur., Nov. 1, in class

Final Exam Schedule: Sat., 12/15, 1:00 – 3:00 p.m., EE 129 (will also schedule [later] somesessions earlier in finals week, for sign-up only)

NASA and Purdue astronaut, Drew Feustel, landed back on Earth this morning (10/04/2018) at about 7:45 a.m. EDT. NASA video of descent and landing on Soyuz MS-08: https://www.youtube.com/watch?v=pxaX7CtdGAg or https://www.youtube.com/watch?v=GWusG5EW3dU

Purdue Today Article (10/4/2018):https://www purdue edu/newsroom/https://www.purdue.edu/newsroom/releases/2018/Q4/astronaut-feustel-scheduled-to-return-to-earth-on-thursday.html

https://www.purdue.edu/newsroom/releases/2018/Q4/astronaut-feustel-scheduled-to-return-to-earth-on-thursday.html

Evaluating the Earthquake Hazard (two main factors* – how large?; how far away? Also, when will it happen?):

1.Frequency of occurrence-- Earthquake statistics --

a probability estimate

How is it estimated?

*Of course, as we have already seen, the quality of

buildings is also very important

-- Paleoseismology – useful for extending historical record for large magnitude (infrequent) events

-- Earthquake Prediction (currently not reliable)

Search for premonitory effects

Prediction implies accurate time,p ,

location, magnitude and scientific basis

-- Forecasting (from frequency-magnitude graphs is much more reliable but much less precise), such as, “the San Francisco bay area has a 63% chance of a 6.7 or grater earthquake occurring in the next 30 years.”

(http://earthquake.usgs.gov/regional/nca/ucerf/)

2. Location

-- Distance to known or expected seismic sources (fault zones)

-- Expected magnitude and attenuation rate (gives expected intensity at location

3 L l it ff t3. Local site effects

-- Possible amplification of shaking caused by liquefaction or thick layers of low-density sedimentary rocks or sediments

4. Building characteristics

-- Earthquake resistant structures

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Timeline of Shaking in the San Francisco Bay area1.7 seconds: Shaking starts on western edge of the city of San Francisco.

http://earthquake.usgs.gov/regional/nca/1906/simulations/

Timeline of Shaking in the San Francisco Bay area1.7 seconds: Shaking starts on western edge of the city of San Francisco.

Santa Rosa

NorthwestSan Andreas Fault

Timeline of Shaking in the San Francisco Bay area2.6 seconds: Strong shaking begins on western edge of San Francisco.

Timeline of Shaking in the San Francisco Bay area3.4 seconds: Strong shaking begins at San Francisco City Hall.

Timeline of Shaking in the San Francisco Bay area4.9 seconds: Shaking begins in the city of Oakland.

Timeline of Shaking in the San Francisco Bay area6.2 seconds: Strong shaking begins in the city of Oakland.

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Timeline of Shaking in the San Francisco Bay area9.0 seconds: Shaking begins in the Palo Alto area.

Timeline of Shaking in the San Francisco Bay area13.0 seconds: Shaking begins in San Jose and Livermore.

Timeline of Shaking in the San Francisco Bay area16.0 seconds: Shaking,Santa Cruz. Strong shaking close to Santa Rosa.

Timeline of Shaking in the San Francisco Bay area21.0 seconds: Strong shaking begins in San Jose

Timeline of Shaking in the San Francisco Bay area30.0 seconds: Strong shaking has enveloped entire San Francisco Bay area.

http://earthquake.usgs.gov/regional/nca/simulations/1906/

Timeline of Shaking in the San Francisco Bay area30.0 seconds: Strong shaking has enveloped entire San Francisco Bay area.

Santa Rosa

http://earthquake.usgs.gov/regional/nca/simulations/1906/

San Andreas Fault (Santa Rosa is about 30 km from the fault), note strong shaking at Santa Rosa due to amplification from a sedimentary basin

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1906 San Francisco earthquake damage at Santa Rosa, CA; there were about 7000 people living in Santa Rosa in 1906 – today, there are about 172,000. http://geomaps.wr.usgs.gov/sfgeo/quaternary/stories/santarosa_damage.html

San Francisco Bay area major faults and probability of M6.7+ earthquake in the next 30 years

150th Anniversary of the150th Anniversary of the Damaging 1868 Hayward Earthquake:Why It Matters and How We Can Prepare for Its Repeatby Tom Brocher, USGS Research Geophysicist online.wr.usgs.gov/calendar/.

Earthquake Hazards - Modes of Building FailureConnections between failure modes observed in shake table testing of models in building contest and earthquake damage to actual buildings

L. Braile, Purdue University, October 2013 (for additional information and sources see EQ Hazards and Photos links at: http://www.eas.purdue.edu/~braile/indexlinks/educ.htm)

Intensity of shaking decreases with distance from epicenter p(MM Intensity scale).

M6.8, 1994 Northridge, California earthquake

Intensity of shaking decreases with distance from epicenter (Peak horizontal acceleration).


Intensity of shaking decreases with distance from epicenter (star; USGS(star; USGS Shake Map).


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Soft first story failure

The Oct., 1989 Loma Prieta Earthquake (M7.0) Earthquake damage.




The Jan., 1994 Northridge Earthquake (M6.7) Earthquake damage.

The October, 1989 Loma Prieta Earthquake (M7.0) Earthquake damage.

Olive View Hospital, 1971 San Fernando Earthquake

Olive View Hospital, 1971 San Fernando Earthquake

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Weak story failure, Kobe, 19951995

Building shifted off foundation


Column failure


Bending


Bending

Inadequate connection to uprights


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High center of mass, resonance Falling objects


Falling objects,partial wall collapse

Falling objects, partial wall collapse


1933 Long Beach Earthquake (~M6.4)

Exploring Planet Earth

Jefferson Jr. HShttp://www.data.scec.org/chrono_index/longbeac.html

Liquefaction, ground failure

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Liquefaction, ground failure Liquefaction, ground failure

Un-reinforced masonry

(Bam, Iran earthquake, 2003, photo from USGS)

Dec. 26, 2003M6.6 Earthquake,Bam, m,Iran,~80% of buildingsdestroyed

1985 MEXICO EARTHQUAKE: CRITICAL STRUCTURES--HOSPITALS

1985 MEXICO EARTHQUAKE: CRITICAL STRUCTURES--HOSPITALS

“Pancaking” Intensity (areas of damage) for Landers 1992 (M7.3) and New Madrid 1811 (M7.3) earthquakes

Note the much larger area of strong shaking in the central and eastern U.S. This is the result of very efficient

http://pasadena.wr.usgs.gov/office/hough/page.nm.html

ywave propagation due to older, cooler lithosphere.

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Sand Blows (white spots; sand “volcanoes”; liquefaction effects) in the bootheel area of SE Missouri fromSE Missouri from the 1811-1812 New Madrid earthquakes. Photo taken in 1953.

~ 1 km

New Madrid earthquakes (1974-1994) and gravity map. Bright colors are higher than normal gravity and indicate relatively dense rocks beneath the surface (but not rightsurface (but not right below the surface because we know that there are relatively thick Mississippi River sediments at the surface).

Geologic model of the New Madrid seismic zone and buried ancient riftancient rift.

Geologic model of the New Madrid seismic zone and buried ancient rift.

Comparison of Frequency Magnitude Plots

100

1000

10000

hq

ua

ke

s G

reat

er

o M

196

0 -

2003

Japan

Alaska

Pacific NW

N. California

S. California

New Madrid

Research on Earthquake probability

Different areas have different recurrence relationships indicating different probability of

Highest probability

1

10

100

3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8

Magnitude (M)

Nu

mb

er o

f E

arth

than

or

Eq

ual

to

44 years of EQ data

~1 M5.5+ in 44 yr

~6 M8+ in 44 yr

probability of earthquakes

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Reducing the Earthquake Hazard:1. Before

-- Know what to do in case of an earthquake-- Make home/office safer-- Have disaster supplies

2. During-- If indoors stay thereIf indoors, stay there-- Take cover (desk or table)-- If outdoors, stay there, move to open area

3. After-- Check utilities, especially gas lines-- Be prepared for aftershocks

(evacuate weakened structures)

VOLCANIC ROCK SAMPLES*:BASALT - - Hawaii, (dark, fine grain, Fe and Mg rich,

low SiO2, 3.0 g/cm3 density)

BASALT - - “aa”, Craters of the Moon, Idaho

RHYOLITE [or ANDESITE, named for Andes Mountains] - - Mt. St. Helens, (lighter color, fine

3grain, high SiO2 (note quartz crystals) 2.7 g/cm3

density)

PUMICE - - Mt. St. Helens

OBSIDIAN - - Volcanic glass

VOLCANIC ASH - - Mt. St. Helens May 18, 1980 eruption

*Shown in class last Thursday

Rhyolite, Basalt, Craters of theBasalt, Hawaii Mt. St Helens Moon, Idaho

Obsidian, OR Pumice and Volcanic Ash Mt. St Helens

VOLCANOES:

1. Importance in Earth history

-- Building of continental crust and differentiation of the Earthdifferentiation of the Earth

-- Development of the atmosphere

-- Deposition of ore minerals

2. Relationship to Plate Tectonics-- Mid-ocean ridges and rifts – mostly basaltic

volcanism (fluid flows)

-- Island arcs, subduction zones – mostlyrhyolite/andesite volcanism (explosive)

-- OTHER (less important)

-- Hotspots (Hawaii)

-- Plateau basalts

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Two major types of volcanism (also see Figure 7.3 in text [Table 7.1 in previous edditions; not correct in 2008 and 2005 editions]):

BASALTIC RHYOLITE - ANDESITE

low SiO2 50%density 3 g/cm3

shield volcanoes

high SiO2 70%density 2.7 g/cm3

composite volcanoesmid-ocean ridgesmelt temp. 1200Clow viscosity

(fluid flows)flow eruptionsExamples: Hawaii,

mid-ocean ridge, Iceland, Cratersof the Moon (ID)

collision zonesmelt temp. 700Chigh viscosity

(sticky lava; also ash)explosive eruptionsExamples: St. Helens,

Andes volc., Vesuvius,Mt. Pele, Pinatubo,Japan volcanoes

Figure 7.3, 8th edition, text, 2017

Andesitic and Rhyolitic Magma are “a little” different but have similar properties and eruptive characteristics, so we group them together

Table 7.1 – 7th edition, text, 2014

Andesitic and Rhyolitic Magma are “a little” different but have similar properties and eruptive characteristics, so we group them together

Vesicular Basalt (low SiO2, fluid flows)

Rhyolite Pumice (high SiO2, viscous flows, explosive)Figure 7.10, text. Types of

volcanoes: Shield (basaltic)and Composite(or stratovolcano;andesite/rhyolite)y )are most important, (Lecture note Figure V).

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Active volcanoes, Figure 7.35, text.

Volcano topography – comparing topographic profiles overEarth and Martian volcanoes

Comparison of topographic profiles over a cinder cone, a composite volcano and a shield volcano (no vertical exaggeration)

Figure 7.13, text

Composite volcano, Kamchatka (note steepsides)

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Photo Ronald Nelson. Mt. Bromo, Indonesia, Kedaluh, East Java, Indonesia National Geographic photo contest, 2016

Mt. Unzen, Japan, above Shimabara City. Eruption of June 3, 1991; 43 people killed. Landslide triggered by eruption and earthquake in 1792 killed 15,000 people. Landslide scar at lower right.

Mt. Unzen pyrocastic flow, June 3, 1991 (http://holykaw.alltop.com/think-lavas-bad-get-load-pyroclastic-flow-video). YouTube video at:

https://youtu.be/Cvjwt9nnwXY

“As if volcanoes weren’t terrifying enough, this footage of a pyroclastic flow, which occurred in Japan in 1991, will have you looking warily at every supposedly dormant volcano you see.The hot gas and rock explosion sends a wave of deadly debris shooting down the valley, and the scene is made even more dramatic when the TV crew catches footage of a man fleeing from the scene.Wikipedia provides more background on the commentary regarding fatalities due to the eruption:A pyroclastic surge killed volcanologists Katia and Maurice Krafft and 41 other

l M t U i J J 3 1991 Th t t d

http://holykaw.alltop.com/think-lavas-bad-get-load-pyroclastic-flow-video

people on Mount Unzen, in Japan, on June 3, 1991. The surge started as a pyroclastic flow and the more energised surge climbed a spur on which the Kraffts and the others were standing…The French couple spent their careers on the edge of volcanoes, knowing their time could be cut short at any point. Their own Wikipedia entry includes the following eerily prescient anecdote:Maurice famously says in that video that “I am never afraid because I have seen so many eruptions in 23 years that even if I die tomorrow, I don’t care”, coincidentally on the day before his, and his wife’s death at Mt. Unzen.”

Plateau (flood) basalts of the Pacific Northwest

Figure 7.25A, textNote layers of basalt lava, erupted on the surface, so youngest above and oldest below.

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VOLCANOES - - Hawaii:(Example of basaltic flow eruptions)

KEY CONCEPTS:

- - Plate tectonic setting: mostly mid-ocean ridge or hotspot

- - Relatively “gentle”, and more predictable, low viscosity (fluid; less SiO2) flow eruptions and lesser hazards

-- Basaltic (less SiO2) lavas from Earth’s “normal” upper mantle about 60 to 100 km deep

Basaltic volcanism occurs along the mid-ocean ridge divergent boundaries (melting of “normal” mantle rocks), Figure 7.36, text.

Anatomy of a Shield Volcano

Figure 7.12, text

Chain of islands and seamounts extending from Hawaii to Aleutian trench – the track of the Hawaiian hotspot (Figure 5.36, text)

8. Hotspot tracks (like Hawaii)

Figure 5.26, text (age in millions of

years)

(like Hawaii) show direction of motion of the lithosphere over a hotspot (by age of volcanic activity) http://www.minerals.si.edu/tdpmap/ (Interactive Map)

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http://pubs.usgs.gov/imap/2800/


From This Dynamic Planet map and website: http://pubs.usgs.gov/imap/2800/

Volcano National Park, Hawaii Volcano National Park, Hawaii

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Divergent Plate Boundary

Iceland: The Mid Atlantic Ridge exposed on the continent

Krafla geothermal power plant

drone footage of the Iceland lava riverhttp://www.barcroft.tv/dji-drone-camera-lava-lake-holuhraun-iceland

flash flooding caused by the volcanoeshttps://www.youtube.com/watch?v=qoGKicdPM7E

Shield (basaltic) volcanoes: a broad, domed volcano with gently sloping sides, characteristic of the eruption of fluid, basaltic lava.

Mauna Kea, Hawaiʻi, a shield volcano on the Big Island of Hawaii

Composite volcanoes: (or stratovolcano; andesite/rhyolite) a conical volcano built up by alternating layers of lava, pumice and ash, a steep profile with a summit crater.The lava flowing from stratovolcanoes typically cools and hardens before spreading far due to high viscosity.

Mt. Fuji is a dormant composite volcano that is the highest mountain in Japan.

Some interesting volcano photos …

Photo and caption by Vladimir Voychuk. “This is how planet’s fiery breathe looks like. When volcano wakes up, lava’s streams and their blazing glow are visible even hundreds of kilometers away. The eruption of Klyuchevskaya sopka. Kamchatka.” http://photography.nationalgeographic.com/nature-photographer-of-the-year-2016/gallery/week-11-landscape/16

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Photo and caption by kousuke kitajima. “Ōishi, Yamanashi, Japan.” http://photography.nationalgeographic.com/nature-photographer-of-the-year-2016/gallery/week-6-landscape/1

Photo and caption by Takashi. “It was very chilly morning. All of the tree was covered with soft rime. The soft rime was dyed to sakura (cherry) color by rising sun. It was so very beautiful view.” http://photography.nationalgeographic.com/nature-photographer-of-the-year-2016/gallery/week-6-landscape/12

Photo Ronald Nelson. Mt. Bromo, Indonesia, Kedaluh, East Java, Indonesia National Geographic photo contest, 2016

Photo and caption by Takashi. A baby cloud had born at dawn. The baby cloud had grown bigger and bigger than before. “When it came the time of the morning glow, It had grown to many huge lenticular clouds.” http://photography.nationalgeographic.com/nature-photographer-of-the-year-2016/gallery/week-1-landscape/5

“Lava Falls." Photo and caption by TETSUYA NOMURA. “Lava falls into the sea. Explosions occurred and there was warm smoke. My camera lens became fog up.” Hawaii. http://travel.nationalgeographic.com/photographer-of-the-year-2017/gallery/peoples-choice-all/15

Photo and caption by Greg Metro. “Nyiragongo Volcano's crater lake is the largest lava lake in the world.” http://travel.nationalgeographic.com/photographer-of-the-year-2017/gallery/week-7-all/29

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Photo and caption by Florent Mamelle. “Batu Rara is a volcano located on Komba island, off Lembata in Indonesia. I have been climbing volcanoes for many years, but this is the first time I witness how the gas pushes the rocks. As the crater partly collapsed, we can see both the bottom of the explosion within the rim, and the full cloud.” http://photography.nationalgeographic.com/nature-photographer-of-the-year-2016/gallery/week-11-action/8

Crazy Man! Photo and caption by Gaby Barathieu. “An unconscious person certainly ascended the cone to see the lava lake inside. He stayed at least 2 minutes, without any protection. “ The September 16, 2016 eruption of Le Tampon, Reunion, Reunion. http://photography.nationalgeographic.com/nature-photographer-of-the-year-2016/gallery/week-5-action/1

plate-boundary volcanoes

Ocean – Continent Collision

Volcanic Island Arc Mid-ocean Ridges

Hot-Spot Volcanoes

Hot source: fixed-position mantle plume Column of very hot rock rising from deep mantle

Active hot-spot volcano occurs at the end of a chain of extinct volcanoes

• Hot-spot track: the chain of

extinct volcanoes, forms when

the overlying plate moves over

a fixed plume

Hot-Spot Volcanoes Active volcano represents

the present‐day location of the mantle plume

Extinct volcanoes: locations once over the mantle plume but progressively moved off

Hot spot is not related

to plate boundaries

The Hawaiian Islands are hot-spot volcanoes

https://www.youtube.com/watch?v=bYv6V5EJAKc

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Hot spots within continents: Africa, Yellowstone.

The tracks provide clues to the direction of plate movement.

Yellowstone hotspot track

From Smith and Siegel, “Windows into the Earth”

EAPS 10000 – Planet EarthProf. L. Braile

2271 HAMP (CIVL), [email protected] and Volcanic Hazards:

Volcanic rocks, types of volcanoes, hazards

Hawaiian (basaltic) and St. Helens (rhyolite/andesite) l l f l i dvolcanoes as examples of non-explosive and

explosive volcanoes

Hw 3 is due on Tuesday, October 23

We will complete the Earth science unit and the Oceanography unit before Exam II

Exam II will be Thursday, November 1

We will discuss Exam II in class in Thursday, Oct. 25

EAPS 10000 – Planet EarthProf. L. Braile

2271 HAMP (CIVL), [email protected] and Volcanic Hazards:

Volcanic rocks, types of volcanoes, hazards

Hawaiian (basaltic) and St. Helens (rhyolite/andesite) volcanoes as examples of non explosive andvolcanoes as examples of non-explosive and explosive volcanoes

Videos of basaltic volcanism

https://www.businessinsider.com/hurricane-michael-approaches-florida-2018-10 - Hurricane Michael - third strongest in last 50 years.

Coastline f

Hurricane Michael -https://www.miamiherald.com/news/weather/hurricane/article219864155.html

Coastline of Florida

of Florida

Gulf of Mexico

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Hurricane Michael at landfall, infrared-https://www.washingtonpost.com/weather/2018/10/11/michael-made-history-one-top-four-strongest-hurricanes-strike-united-states/?noredirect=on&utm_term=.2e909e89db4c

https://marine.rutgers.edu/cool/sat_data/?nothumbs=0&product=sst_comp&region=gulfmexico – Sea surface water temperatures, 10/12/2018, Hurricane Michael

https://www.nytimes.com/2018/10/14/us/hurricane-michael-florida-mexico-beach-house.html - Hurricane Michael damage

VOLCANOES - - Mt. St. Helens:(Example of a composite volcano eruption -- May 18, 1980)

KEY CONCEPTS:

Plate tectonic setting, collision or convergent boundaryL hi t f ti f C d l Long history of eruptions of Cascade volcanoes (example of uniformitarianism - - 1980 eruption of Mt. St. Helens was not unusual, geologically)

Difficulty of predicting geologic hazard events and social/government/economic implications

High volcanic hazard of explosive (high SiO2) volcanoes

Two major types of volcanism (also see Figure 7.3 in text [Table 7.1 in previous edditions; not correct in 2008 and 2005 editions]):

BASALTIC RHYOLITE - ANDESITE

low SiO2 50%density 3 g/cm3

shield volcanoes

high SiO2 70%density 2.7 g/cm3

composite volcanoesmid-ocean ridgesmelt temp. 1200Clow viscosity

(fluid flows)flow eruptionsExamples: Hawaii,

mid-ocean ridge, Iceland, Cratersof the Moon (ID)

collision zonesmelt temp. 700Chigh viscosity

(sticky lava; also ash)explosive eruptionsExamples: St. Helens,

Andes volc., Vesuvius,Mt. Pele, Pinatubo,Japan volcanoes

Rhyolite-Andesite volcanism occurs along convergent boundaries (melting of subducted lithosphere and mantle and crust above the slab; island arc or ocean-continent collision), Figure 7.34, text.

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Mt. St. Helens -- Prior to the 1980 Eruption

Figure 7.1, text

07_07

A strato- or composite volcanocomposed of layers of lava and ash (pyroclastic material)Figure 7.11, text.

07_07

A strato- or composite volcano composed of layers of lava and ash (pyroclastic material)Figure 7.21, text.

Volcanic hazards: Explosive eruption, lava flows, pyroclastic flows (glowing avalanche), volcanic bombs, toxic gasses, mud flows, landslides, ash fall, and ash cloud

07_01RMt. St. Helens after May 18, 1980 eruption

Also see Figure 7.1, text

Mt. St. Helens After the 1980 Eruption

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Pyroclastic flow (glowing avalanche) on Mt. St. Helens

(also see (Figure 7.5 and

7.18, text)

Pyroclastic flow (glowing avalanche) on Mt. Unzen, Japan

Figure 7.21, text

Figure 7.19, text

~2 km

Digital satellite image of Mt. St. Helens after the 1980 eruption (from Google Earth). In Google Earth one can zoom in and out, rotate the image and “fly in” to this and other locations.

Digital satellite image of Mt. St. Helens after the 1980 eruption (from Google Earth). In Google Earth one can zoom in and out, rotate the image and “fly in” to this and other locations.

http://volcanoes.usgs.gov/volcanoes/st_helens/st_helens_geo_hist_101.html

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Lava Dome (since 1980 eruption)

http://volcanoes.usgs.gov/volcanoes/st_helens/st_helens_gallery_28.html

Lava Dome (since 1980 eruption)

http://volcanoes.usgs.gov/volcanoes/st_helens/st_helens_gallery_28.html

http://www.universetoday.com/9939/infrared-view-of-mount-saint-helens/

Infrared satellite image – red is vegetation



Infrared satellite image, August 29, 1979D

http://www.livescience.com/6452-striking-images-mount-st-helens.html

2 km

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Infrared satellite image, September 24, 1980


2 km

Infrared satellite image, September 10, 2009 (almost 30 years after eruption)


2 km

20 km

Yellowstone Caldera~65 x 45 km

Calderas

Island ParkIsland Park Caldera

20 km


Yellowstone NP and Volcano

Island ParkIsland Park Caldera

Grand Prismatic Spring (hot spring). Yellowstone National Park

Note people on walkway for scale

Colors are due to algae that exists at various temperatures in the hot water from the hot spring

Caldera (collapsed volcano) Figure 7.22, text

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Caldera (Crater Lake, Oregon) Figure 7.22, text

20 km

Yellowstone Lake

Yellowstone Caldera – Satellite Image. Most recent large eruptions – 2.1 mya (~2450 km3 ejecta) , 1.3 mya (~280 km3), 640,000 years ago (~1000 km3) and eruptions of rhyolite lava in the caldera between 150,000 and 70,000 years ago (~1000 km3).

Yellowstone Caldera – Satellite Image, 3-D Perspective View.

Caldera formation and Crater Lake (Figure 7.22, Text)

Yellowstone Caldera and area of significant ash fall from most recent“super-volcano” eruptions (Figure 7.23, Text)

In the following slides, we illustrate the relative sizes of eruptions and craters produced by the eruption …

2 km

View from Coast

Mt. Vesuvius and Crater (~0.5 km in diameter; ~9 km from Naples, Italy) – Satellite Image. Famous eruption, pyroclastic flows that covered the cities of Pompeii and Herculaneum in 79 A.D. (~4 km3 of ejecta). Most recent eruption was 1944.

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10 km

Spirit Lake

Mt. St. Helens and Crater (~2 km in diameter; Washington State) – Satellite Image. Well documented explosive eruption in 1982 (~3 km3 of ejecta) killed 57 people. Previous eruptions (about 3300-3900 years ago) erupted ~10 km3 of ash and lava.

Mt St Helens and Panoramic view of Modern Crater (~2 km in diameter;

Lava dome built since 1980 eruption

Crater Rim (view to N)

Mt. St. Helens and Panoramic view of Modern Crater (~2 km in diameter; Washington State) – Satellite Image.

Before 1980 Eruption After 1980 Eruption

Spirit Lake

Spirit Lake

2 km

Close-up View of Mt. St. Helens Crater – Satellite Image.

2 km Crater

Tambora Volcano (Indonesia) and Crater (~6 km in diameter) – Satellite Image. Explosive eruption in 1815 (~160 km3 of ejecta) was the largest in historic time, lowered the Earth’s atmospheric temperature by 3 oC, and produced the “year without a summer” in North America in 1816.

Figure 7.9, text

4 km

Crater Lake (formerly Mt. Mazama), Oregon (~8 km in diameter) – Satellite Image. Explosive eruption about 6700 years ago (~50 km3 of volcanic ejecta, and about 50 km3 of the 3700 m tall mountain was blasted away)

Aerial View

http://pubs.usgs.gov/fs/2002/fs092-02/

Crater Lake (formerly Mt. Mazama), Oregon(~8 km in diameter) – Lake Bathymetry

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20 km


St. Helens Crater ~2 km

Vesuvius Crater~0.5 km

Tambora Caldera~6 km

Comparison of crater/caldera size – all images at same scale

Crater Lake~8 km

Island ParkCaldera~20 km

0

http://pubs.usgs.gov/fs/2005/3024/fs2005-3024.pdf

How Big Were the Yellowstone Eruptions? About 6,000 times larger than the 1980 eruption of Mt. St. Helens!!!

Others: Long Valley, CA 760,000 yrs ago, ~580 km3; Valles, NM 1.1 mya, ~600 km3; Toba, Indonesia 70,000 yrs ago, ~500 km3.http://pubs.usgs.gov/fs/2005/3024/fs2005-3024.pdf

View these as spheres, not circles, for accurate representations of relative

Comparison of eruption sizes.http://volcanoes.usgs.gov/volcanoes/yellowstone/yellowstone_sub_page_49.html

of relative volumes of eruptions

Planet Earth EAPS 10000-001

Documents

Transcript of Planet Earth EAPS 10000-001