© 2015 Pearson Education, Inc. Laboratory Manual in Physical Geology, 10e Image PPTs Chapter 16 Earthquake Hazards and Human Risks

© 2015 Pearson Education, Inc. Fig

© 2015 Pearson Education, Inc. Fig Fig seismograph A seismograph measures relative movement of the ground to a stationary pen.

© 2015 Pearson Education, Inc. Richter Scale The Richter Scale is a logarithmic scale that measures the magnitude of an earthquake. A magnitude 5.0 quake has Earth movements ten times greater than a 4.0 magnitude quake (= ~32x the energy released). In theory, the local crust melts in a magnitude 10 or greater quake. The most energetic quake recorded to date had a magnitude of approximately 9.0.

© 2015 Pearson Education, Inc. Fig B o d y W a v e s S u r f a c e W a v e s

© 2015 Pearson Education, Inc. P or Primary Waves: Compression/Expansion (“Sound”) Solid and Liquid, through the Earth (Body Wave) S or Secondary Waves: Transverse Solid Only, through the Earth (Body Wave) Surface (Love/Raleigh) Waves: Transverse/Circular (“Ocean”) Solid Only, Near land surface Velocity ~ Density? Density ~ Depth?

© 2015 Pearson Education, Inc. Seismogram Seismogram – record of ground movement produced by a seismograph P-waves arrive at the station first, followed by S-waves and later by surface waves. Because S-waves travel more slowly than P-waves, the farther the waves have traveled, the farther behind the S-waves will be and the longer the time gap until they arrive. P-wave velocity will always be higher than S-wave velocity, no matter what the waves travel through.

© 2015 Pearson Education, Inc. P or Primary Waves: Fastest – Arrives First S or Secondary Waves: Middle Surface (Love/Raleigh) Waves: Slowest – Arrives Last Time: 7:14 = 14 minutes after 7 oclock Difference in Arrive Times between the P and S Waves 7:17.4 – 7:14.2, ignore the 7: minutes – 14.2 minutes = ? 3.2 Minutes Two cars leave Rock Hill, Galleria Mall, I-77 at the same time to Charleston. One drives 60 mph (S Wave) and one drives 80 mph (P Wave) At Columbia, 60 miles, 60 minutes & 45 minutes Arrival time difference: 15 minutes At Charleston, 240 miles, 3.75 hours and 3 hours Arrival time difference: 0.75 hours or 45 minutes

© 2015 Pearson Education, Inc.

P Wave Each line is representative of a particular type of seismic wave. Which is the fastest wave? Which is the next fastest wave? Why curved lines? Why straight line? S Wave L Wave

© 2015 Pearson Education, Inc. Fig Earthquake in Pacific Northwest Waves arrive in Denver distance: 2000 km Waves arrive in St. John’s distance: 5300 km Waves arrive in Lima distance: 9000 km

© 2015 Pearson Education, Inc. Fig The difference between the arrival times for P-waves and S-waves can be used to determine the distance to the earthquake’s epicenter

© 2015 Pearson Education, Inc. P-Wave: 8:07.4 S-Wave: 8: – 7.4 = 4.1 minutes

© 2015 Pearson Education, Inc. L Wave S Wave P Wave ~ 2,600 km 4.1 minutes

© 2015 Pearson Education, Inc.

Right Lateral vs. Left-Lateral Strike-Slip Fault

© 2015 Pearson Education, Inc.

ACTIVITIES: HANDOUT: By Table Spring and Compression/Lateral Waves As available (one spring, short exercise) Demonstration of method 10 meter = ~33 feet (32.81 feet) 2 Way = 2 Round Trips = 40 m 4 Way = 4 round Trips =80 m

© 2015 Pearson Education, Inc. ACTIVITIES: MANUAL: By Table 16.2: A (discuss only), B, C, D 16.3: All 16.4: A, C