Warm Up 11/1 1. 1. Which of the following is NOT a characteristic of S waves? a. They cannot be transmitted through water or air. b. They shake particles.

Warm Up 11/1Warm Up 11/11. Which of the following is NOT a characteristic of S waves?

a. They cannot be transmitted through water or air.b. They shake particles at right angles to the direction the waves travel.c. They travel more slowly than P waves.d. They temporarily change the volume of material by

compression and expansion.2. The trace that records an earthquake from seismic

instruments is called a ____.a. richtergram c. seismogramb. seismograph d. magnitude

3. The distance between a seismic station and the earthquake epicenter is determined from the ____. a. measurement of the amplitude of the surface wave

b. calculation of the earthquake magnitudec. arrival times of P and S wavesd. intensity of the earthquake

Answers: 1) d. 2) c. 3) c.Answers: 1) d. 2) c. 3) c.

Destruction from Destruction from EarthquakesEarthquakes

Chapter 8, Section 3Chapter 8, Section 3

Seismic VibrationsSeismic Vibrations The damage to buildings and other The damage to buildings and other

structures from earthquakes depends on structures from earthquakes depends on several factors. several factors. The three factors include The three factors include the intensity and duration of the vibrations, the intensity and duration of the vibrations, the nature of the material on which the the nature of the material on which the structure is built, and the design of the structure is built, and the design of the structure.structure.

Engineers have learned that unreinforced Engineers have learned that unreinforced stone or brick buildings are the most stone or brick buildings are the most serious safety threats during earthquakesserious safety threats during earthquakes

Liquefaction –Liquefaction – loosely consolidated loosely consolidated sediments are saturated with water and sediments are saturated with water and turned into a liquid that is not able to turned into a liquid that is not able to support buildingssupport buildings

Seismic DamageSeismic DamageLiquefaction – Niigata, Japan 1964

Ground Shaking – Loma Prieta, CA 1989

Concept CheckConcept Check

When does liquefaction occur?When does liquefaction occur? When loosely consolidated soils When loosely consolidated soils

saturated with water are shaken by saturated with water are shaken by earthquake wavesearthquake waves

TsunamisTsunamis Tsunamis –Tsunamis – A large water wave caused by A large water wave caused by

seismic waves seismic waves A tsunami triggered by an earthquake A tsunami triggered by an earthquake

occurs where a slab of the ocean floor is occurs where a slab of the ocean floor is displaced vertically along a faultdisplaced vertically along a fault

A tsunami also can occur when the A tsunami also can occur when the vibration of a quake sets an underwater vibration of a quake sets an underwater landslide into motionlandslide into motion

A tsunami can travel across the ocean at a A tsunami can travel across the ocean at a speed of 500-950 km/hrspeed of 500-950 km/hr

When the wave enters shallow coastal When the wave enters shallow coastal waters, it will slow down and begin piling waters, it will slow down and begin piling on top of itself to reach a height on top of itself to reach a height sometimes greater than 30 meterssometimes greater than 30 meters

TsunamisTsunamis

Tsunami Travel Time to Tsunami Travel Time to HonoluluHonolulu

Indonesia Tsunami – 2004Indonesia Tsunami – 2004

Indonesia Tsunami – 2004Indonesia Tsunami – 2004

Concept CheckConcept Check

At what point does the tsunami gain At what point does the tsunami gain the most height?the most height?

When it enters shallow watersWhen it enters shallow waters

Other DangersOther Dangers The greatest damage to structures is The greatest damage to structures is

from landslides and ground from landslides and ground subsidence, or the sinking of the subsidence, or the sinking of the ground triggered by vibrationsground triggered by vibrations

The violent shaking can cause water The violent shaking can cause water and gas lines to ruptureand gas lines to rupture

Fire is also a threat, as witnessed by Fire is also a threat, as witnessed by the large-scale destruction of San the large-scale destruction of San Francisco when their gas and electric Francisco when their gas and electric lines were cut along with the water lines were cut along with the water lines needed to put out the fireslines needed to put out the fires

Other DangersOther Dangers

Fire – San Francisco, 1906

Landslide – Turnnagin Heights, Alaska, 1964

Predicting EarthquakesPredicting Earthquakes The goal of short-range prediction is to The goal of short-range prediction is to

provide an early warning of the location provide an early warning of the location and magnitude of a large earthquakeand magnitude of a large earthquake

Methods for short-range predictions of Methods for short-range predictions of earthquakes have NOT been successfulearthquakes have NOT been successful

Long-range predictions give the probability Long-range predictions give the probability of a certain magnitude earthquake of a certain magnitude earthquake occurring within 30 to 100-plus yearsoccurring within 30 to 100-plus years

Seismic gap – Seismic gap – an area along a fault where an area along a fault where there has not been any earthquake activity there has not been any earthquake activity for a long period of timefor a long period of time

Scientists don’t yet understand enough Scientists don’t yet understand enough about how and where earthquakes will about how and where earthquakes will occur to make accurate long-term occur to make accurate long-term predictionspredictions

Probability of Earthquakes Probability of Earthquakes Along the San Andreas FaultAlong the San Andreas Fault

Shaking Hazard for Southern Shaking Hazard for Southern CaliforniaCalifornia

AssignmentAssignment

Read Chapter 8, Section 3 (pg. 229-Read Chapter 8, Section 3 (pg. 229-232)232)

Do 8.3 Assessment #1-6 (pg. 232)Do 8.3 Assessment #1-6 (pg. 232)