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An earthquake (also known as a quake, tremor or temblor) is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an ...

An earthquake (also known as a quake, tremor or temblor) is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time.
Earthquakes are measured using observations from seismometers. The moment magnitude is the most common scale on which earthquakes larger than approximately 5 are reported for the entire globe. The more numerous earthquakes smaller than magnitude 5 reported by national seismological observatories are measured mostly on the local magnitude scale, also referred to as the Richter scale.

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    Op ch10 lecture_earth3, earthquakes Op ch10 lecture_earth3, earthquakes Presentation Transcript

    • Chapter 10 A Violent Pulse: Earthquakes LECTURE OUTLINE earth Portrait of a Planet Third Edition ©2008 W. W. Norton & Company, Inc. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • A Violent Pulse: Earthquakes Prepared by Ronald Parker Earlham College Department of Geosciences Richmond, Indiana Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • What Is an Earthquake?  Earth shaking caused by a rapid release of energy. Due to tectonic stresses that cause rocks to break.  Energy moves outward as an expanding sphere of waves.  This waveform energy can be measured around the globe.   Earthquakes destroy buildings and kill people.   3.5 million deaths in the last 2,000 years. Earthquakes are common. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Seismicity  Seismicity (earthquake activity) occurs due to… Motion along a newly formed crustal fracture (fault).  Motion on an existing fault.  A sudden change in mineral structure.  Inflation of a magma chamber.  Volcanic eruption.  Giant landslides.  Meteorite impacts.  Nuclear detonations.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Faults and Earthquakes  Most earthquakes occur along faults. Faults are crustal fractures that move rock masses.  The amount of movement is termed displacement.  Displacement is also called offset, or slip.   Markers may reveal the amount of offset. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Concepts  Hypocenter (focus) - The spot within the Earth where earthquake waves originate. Usually occurs on a fault surface.  Earthquake waves expand outward from the hypocenter.   Epicenter – Land surface above the hypocenter. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Faults and Fault Motion Faults are like planar breaks in blocks of crust.  Most faults slope (although some are vertical).  On a sloping fault, crustal blocks are classified as:  Footwall (block below the fault).  Hanging wall (block above the fault).  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Fault Types  Fault type based on relative block motion.  Normal fault Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Fault Types  Fault type based on relative block motion.  Reverse fault Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Fault Types  Fault type based on relative block motion.  Thrust fault Special kind of reverse fault. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Fault Types  Fault type based on relative block motion.  Strike-slip fault Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Fault Types  Fault type based on relative block motion.  Oblique-slip fault A combination of dip-slip and strike-slip. Most faults display an oblique-slip character. Pure dip-slip or strike-slip are rare. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Faults and Fault Motion  Faults are commonplace in the crust. Active faults – Ongoing stresses produce motion.  Inactive faults – Motion occurred in the geologic past.   Displacement can be visible. Fault trace – A surface tear.  Fault scarp – A small cliff.   Blind faults are invisible. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Fault Initiation Tectonic forces add stress to unbroken rocks.  The rock deforms slightly (elastic strain).  Continued stress will cause growth of cracks.  Eventually, cracks grow to the point of failure.  When the rock breaks, elastic strain transforms into brittle deformation, releasing earthquake energy.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Fault Motion Faults move in jumps.  Once motion starts, it quickly stops due to friction.  Eventually, strain will build up again, causing failure.  This behavior is termed stick-slip behavior.  Stick – Friction prevents motion.  Slip – Friction briefly overwhelmed by motion.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Fault Motion When rocks break, stored elastic strain is released.  This energy radiates outward from the hypocenter.  The energy, as waves, generates vibrations.  Vibrations cause motion, as when a bell is rung.  Foreshocks and aftershocks are common.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Amount of Displacement  Displacement scale varies from small to large. Large events tear huge fault segments 100s of kms long.  Displacement maxima near hypocenter / epicenter.  Displacement diminishes with distance.  Faulting may result in uplift or subsidence.  Changes are measureable using interferometry  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Seismic Waves  Body waves – Pass through Earth’s interior.  Compressional or Primary (P) waves Push-pull (compress and expand) motion. Travel through solids, liquids, and gases. Fastest. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Seismic Waves  Body waves – Pass through Earth’s interior.  Shear or Secondary (S) waves “Shaking" motion. Travel only through solids; not liquids. Slower. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Seismic Waves  Surface waves – Travel along Earth’s surface.  Love waves – S-waves intersecting the surface. Move back and forth like a writhing snake.  Rayleigh waves – P-waves intersecting the surface. Move like ripples on a pond.  These waves are the slowest and most destructive. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Seismology Seismology is the study of earthquake waves.  Seismographs - Instruments that record seismicity.    Worldwide, they detect earthquakes anywhere on Earth. Seismology reveals size and location of earthquakes. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Seismograph Operation  A seismograph measures… Wave arrival times  Magnitude of ground motion.  Straight line = background.  1st wave causes frame to sink (pen goes up).  Next vibration causes opposite motion.  Seismograph preserves a record of wave arrivals.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Seismograph Operation  Waves always arrive in sequence. P-waves 1st.  S-waves 2nd.  Surface waves last.   Wave arrivals are captured by the seismograph. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Locating an Epicenter P- and S-waves travel at different velocities.  1st arrivals of P- and S-waves varies with distance.  A travel-time graph plots the distance of each station to the epicenter.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Locating an Epicenter  Data from 3 stations can pinpoint the epicenter.  A circle is drawn around each station. The radius is equal to the distance to epicenter. Circles around 3 or more stations will intersect.  The point of intersection is the epicenter. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Size  Two means of describing earthquake size: Intensity.  Magnitude.   Mercalli Intensity Scale.     Intensity – The degree of shaking based on damage. Roman numerals assigned to different levels of damage. Damage occurs in zones. Damage diminishes in intensity with distance. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Size  Magnitude – The amount of energy released. Maximum amplitude of motion from a seismogram.  Value is normalized for seismograph distance.   Several magnitude scales. Richter.  Moment.   Magnitude scales are logarithmic.  Increases of 1 unit = 10-fold increase in ground motion. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Measuring Earthquake Size  Earthquake energy release can be calculated. M6.0 – Energy of the Hiroshima bomb.  M8.9 – Annual energy released by all other earthquakes.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Measuring Earthquake Size  Small earthquakes are frequent.   ~100,000 magnitude 3 / year. Large earthquakes are rare.  32 magnitude 7 earthquakes / year. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Occurrence Earthquakes linked to plate tectonic boundaries.  Shallow – Divergent and transform boundaries.  Intermediate and deep – Convergent boundaries.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Focal Depths  Shallow – 0-20 km. Along the mid-ocean ridge.  Transform boundaries.  Shallow part of trenches.  Continental crust.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Focal Depths  Intermediate and deep earthquakes occur along the subduction trace, the Benioff-Wadati zone. Intermediate – 20-300 km - Downgoing plate still brittle.  Deep - 300-670 km - Mineral transformations?   Earthquakes rare below 670 km (mantle is ductile). Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Convergent Boundaries  Cities near subduction zones have to contend with frequent earthquakes. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Continental Earthquakes  Earthquakes in continental crust. Continental transform faults (San Andreas, Anatolian).  Continental rifts (Basin and Range, East African Rift).  Collision zones (Himalayas, Alps).  Intraplate settings (ancient crustal weaknesses).  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • San Andreas Fault The Pacific plate meets the North American plate.  The San Andreas is a very active strike-slip fault.  A very dangerous fault; hundreds of earthquakes / yr.  San Francisco - Destroyed in 1906.  Loma Prieta, 1989, World Series.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Intraplate Earthquakes 5% of earthquakes are not near plate boundaries.  Intraplate earthquakes are not well understood.  Remnant crustal weakness in failed rifts or shear zones?  Stress transmitted inboard?  Isostatic adjustments?   Clusters New Madrid, Mo.  Charleston, S.C.  Montral, P.Q.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Damage Earthquakes kill people and destroy cities.  The damage can be heartbreaking and horrific.  Knowledge improves odds of survival.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Damage  Ground shaking and displacement. Earthquake waves arrive in a distinct sequence.  Different waves cause different motion.   P-waves are the 1st to arrive.  They produce a rapid up-and-down motion. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Damage  S-waves arrive next. They produce a pronounced back-and-forth motion.  This motion is usually much stronger than P-waves.  S-waves cause extensive damage.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Damage  Surface waves lag behind S-waves. Love waves are the first to follow.  Ground writhes like a snake.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Damage  R-waves are the last to arrive. The land surface behaves like ripples in a pond.  These waves may last longer than others.  Cause extensive damage.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Damage  Severity of shaking and damage depends on… Magnitude (energy) of the earthquake. More = more.  Distance from the hypocenter.  Intensity and duration of the vibrations.  The nature of the subsurface material.  Bedrock transmits waves quickly = less damage Sediments bounce waves = amplified damage. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Damage  Effects on buildings.  Slabs disconnect.  Facades delaminate.  Bridges topple.  Bridges come apart. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Damage  Shaking effects on buildings.  Masonry disintegrates.  Buildings collide.  Slopes collapse. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Damage  Anchorage, Alaska, 1964
    • Earthquake Damage  Turkey, 1999
    • Earthquake Damage  Kobe, Japan, 1995
    • Earthquake Damage  Armenia, 1999
    • Earthquake Damage  Landslides and avalanches. Shaking causes slopes to fail.  Hazardous slopes bear evidence of ancient slope failures.  Rockslides or snow avalanches follow earthquakes in uplands.  An earthquake started the landslide that uncorked Mt. St. Helens on May 18, 1980.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Damage  Liquefaction – Waves liquefy H2O-filled sediments. High pore pressures force grains apart reducing friction.  Liquefied sediments flow as a slurry.  Sand becomes “quicksand”: clay becomes “quickclay.”  Sand dikes. Sand volcanoes. Contorted layering. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Liquefaction Water-saturated sediments turn into a mobile fluid.  Land will slump and flow.  Buildings may founder and topple over intact.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Damage  Fire is a common hazard following earthquakes. Shaking topples stoves, candles, and power lines.  Broken gas mains and fuel tanks ignite a conflagration.  Earthquakes destroy critical infrastructure such as water, sewer, telephone, and electrical lines as well as roads.  Firefighters powerless.  No road access. No water. Too many hotspots.  Good planning is crucial to saving lives. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Damage  Earthquake devastation fuels disease outbreaks. Food, water, and medicines are scarce.  Basic sanitation capabilities disabled.  Hospitals damaged or destroyed.  Health professionals overtaxed.  There may be many decaying corpses.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Damage  Tsunamis or seismic sea waves (not tidal waves). Tsunamis result when earthquakes change the seafloor.  Normal faulting drops the seabed; thrusting raises it.  This displaces the entire volume of overlying water. A giant mound (or trough) forms on the sea surface. This feature may be enormous (up to a 10,000 mi2 area). Feature collapse creates waves that race rapidly away. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Damage Destructive tsunamis occur frequently - about 1/yr.  Many tsunami disasters dot recorded history.  94 destructive tsunamis in the last 100 years.  51,000 victims (not including 12/26/04)   Future tsunami disasters are inevitable.   Growing human population in low-lying coastal areas. Education about tsunamis can save many lives. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Tsunami vs. Wind Waves  Wind waves      Influence the upper ~100 m. Have wavelengths of several 10s to 100s of meters. Wave height and wavelength related to windspeed. Wave velocity maximum several 10s of kph. Waves break in shallow water and expend all stored energy. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak  Tsunami waves      Influence entire water depth Have wavelengths of several 10s to 100s of kilometers. Wave height and wavelength unaffected by windspeed. Wave velocity maximum several 100s of kph. Waves come ashore as a raised plateau of water that pours onto the land. Chapter 10: A Violent Pulse: Earthquakes
    • Tsunami Behavior Tsunamis race at jetliner speed across the ocean.  They may be almost imperceptible in deep water.  Low wave height (amplitude).  Long wavelength (frequency).   As water shallows, waves slow from frictional drag.  Waves grow in height, reaching 10-15 m or more. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Tsunami  Tsunami destruction of the coast depends upon…  Offshore bathymetry. Broad shallows increase amplitude but sap wave energy. Quick deep-to-shallow transition – Deadliest condition. Waves have maximum energy. Wave heights are modest. Water pours onto land as a sheet.  Topography of shore. Broad, low land – Maximum damage. Steep rise of land – Less damage. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Tsunami Reality  The Indian Ocean Tsunami On December 26, 2004, a strong megathrust earthquake (M9.0+) originated in the trench to the west of N. Sumatra.  The earthquake was the largest in 40 years.  Displacement exceeded 15 m; rupture > 1100 km long.  The devastating tsunami killed people in 10 countries surrounding the Indian Ocean.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • The Indian Ocean Tsunami  Killed more people than any tsunami on record. At least 283,106 deaths,14,100 still missing (as of 9/25/07).  1,126,900 people were displaced.   Record-setting death toll. The earthquake was so large and the tsunami spread fast.  Coasts were full of Christmas tourists.  Source: USGS Earthquake Hazards Program, Most Destructive Earthquakes http://earthquake.usgs.gov/regional/world/most _destructive.php/ _destructive.php/ Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • The Indian Ocean Tsunami Destroyed coastlines around the Indian Ocean.  Huge death tolls.  Northern Sumatra.  Thailand.  Malaysia.  Sri Lanka.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • The Indian Ocean Tsunami  Complete devastation below “run-up” elevation. Dense coastal development in Banda Aceh hardest hit.  Entire communities were erased – buildings and people.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Surviving a Tsunami  Heed natural and official warnings.    Expect many waves.     An earthquake in a coastal setting. Retreat of water from the shore is sign of an impending tsunami. Bigger waves may be next. Wave arrival may last for hours. Abandon belongings. Get to high ground and stay there. Source: Brian F. Atwater and others, 1999, Surviving a Tsunami – Lessons from Chile, Hawaii and Japan, USGS Circular 1187 Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Surviving a Tsunami      Expect roads to be impassable. Climb a sturdy building or a tree. Grab something that floats. Expect lots of debris (sediment, wreckage, corpses). Expect landscape changes. Source: Brian F. Atwater and others, 1999, Surviving a Tsunami – Lessons from Chile, Hawaii and Japan, USGS Circular 1187 Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Tsunami Prediction Scientific modeling predicts tsunami behavior.  Tsunami detection is expanding.  Tsunami detectors are placed on the deep seafloor.  Sense pressure increases from changes in sea thickness.   Prediction / detection can save 1000s of lives. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Prediction Prediction would help reduce catastrophic losses.  Can we predict earthquakes? Yes and no.  They CAN be predicted - long-term (10-100s of years).  They CANNOT be predicted - short-term (hours-months).  Seismic hazards are mapped to assess risk.  This information is useful for…  Developing building codes.  Land-use planning.  Disaster planning.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Prediction  Long-term predictions. Probability of a certain magnitude earthquake occurring on a time scale of 30 to 100 years, or more.  Based on the premise that earthquakes are repetitive.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Prediction  Long-term predictions.  Require determination of seismic zones by… Mapping historical epicenters (after ~ 1950). Evidence of ancient earthquakes (before seismographs). Evidence of seismicity – Fault scarps, sand volcanoes, etc. Historical records. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Prediction  Long-term predictions.  Recurrence interval – Average time between events. Historical records. Geologic evidence – Requires radiometric dating of events. Sand volcanoes. Offset strata. Drowned forests. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Prediction  Long-term predictions.  Seismic gaps, places that haven’t slipped recently, are more likely candidates. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Earthquake Prediction  Short-term predictions. Goal: The location and magnitude of a large earthquake.  Currently no reliable short-range predictions are possible.  Earthquakes do have precursors.  Clustered foreshocks. Crustal strain. Stress triggering.  And, possibly… Water level changes in wells. Gases (Rn, He) in wells. Unusual animal behavior. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Preparing for Earthquakes  We can’t stop them but we can be ready for them. Understand what happens during an earthquake.  Map active faults and areas likely to liquefy from shaking.  Develop construction codes to reduce building failures.  Regulate land use to control development.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • Preparing for Earthquakes  We can’t stop them but we can be ready for them. Train the community in earthquake preparedness.  Run preparedness drills.  Educate individuals on safe behavior and responses.  Keep viable stores of emergency supplies.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes
    • This concludes the Chapter 10 A Violent Pulse: Earthquakes LECTURE OUTLINE earth Portrait of a Planet Third Edition ©2008 W. W. Norton & Company, Inc. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 10: A Violent Pulse: Earthquakes