UNDERSTANDING EARTH, SIXTH EDITION GROTZINGER JORDAN GEOLOGY MEDIA SUITE Chapter 13 Earthquakes 2010 W.H. Freeman and Company
Three different types of seismic waves are recorded by seismographs Key Figure 13.5 (page 303) Go to next slide to begin
Focus Mantle Core S P Seismograph
Seismic waves travel through Earth and over its surface. Focus Mantle Core S P Seismograph
Minutes 0 10 20 30 40 50 P S Surface waves
The waves travel at different speeds and arrive at the seismograph at different times. Minutes 0 10 20 30 40 50 P S Surface waves
Compression wave
P waves are compressional waves that travel quickly through rock. Compression wave
P waves are compressional waves that travel quickly through rock. Compression wave P waves push and pull particles in the direction of their path of travel.
A section of rock expands and contracts.
Wave direction Wave direction
Wave direction Wave direction
Shear-wave crest
S waves travel at about half the speed of P waves. Shear-wave crest
S waves travel at about half the speed of P waves. Shear-wave crest S waves push material at right angles to their path of travel.
A section of rock shears from a square to a parallelogram.
Wave direction Wave direction
Wave direction Wave direction
Wave direction
Surface waves ripple across Earth s surface. Wave direction
Surface waves ripple across Earth s surface. The ground surface moves in a rolling, elliptical motion. Wave direction
Wave direction
The ground shakes sideways, with no vertical motion. Wave direction
Three different types of seismic waves are recorded by seismographs Which list places the different kinds of seismic waves in order of increasing velocity of travel (from slowest to fastest)? A. S wave, P wave, surface wave B. P wave, S wave, surface wave C. Surface wave, S wave, P wave D. Surface wave, P wave, S wave
Three different types of seismic waves are recorded by seismographs Which list places the different kinds of seismic waves in order of increasing velocity of travel (from slowest to fastest)? A. S wave, P wave, surface wave B. P wave, S wave, surface wave C. Surface wave, S wave, P wave D. Surface wave, P wave, S wave
Three different types of seismic waves are recorded by seismographs Through which of the different states of matter can S waves travel? A. Solid only B. Liquid only C. Gas only D. Solid and liquid only E. Solid, liquid and gas
Three different types of seismic waves are recorded by seismographs Through which of the different states of matter can S waves travel? A. Solid only B. Liquid only C. Gas only D. Solid and liquid only E. Solid, liquid and gas
Three different types of seismic waves are recorded by seismographs True or False: As S waves propagate, the medium they travel through moves at right angles to the direction of wave propagation. A. True B. False
Three different types of seismic waves are recorded by seismographs True or False: As S waves propagate, the medium they travel through moves at right angles to the direction of wave propagation. A. True B. False
Earthquakes indicate how tectonic plates interact at their boundaries Earth System Figure 13.12 (page 310) Go to next slide to begin
World seismicity from 1976 to 2002 ASIA EUROPE PACIFIC OCEAN NORTH AMERICA ATLANTIC OCEAN AFRICA INDIAN OCEAN SOUTH AMERICA AUSTRALIA 50 km deep (shallow focus) 50 300 km deep 300 km deep (shallow focus) ANTARCTIC OCEAN
Mid-ocean ridge (divergence) Transform fault (lateral shearing) Rift valley (divergence) Lithosphere Asthenosphere
Mid-ocean ridge (divergence) Normal faulting Transform fault (lateral shearing) Rift valley (divergence) Lithosphere Asthenosphere
Mid-ocean ridge (divergence) Normal faulting Transform fault (lateral shearing) Rift valley (divergence) Lithosphere Asthenosphere Shallow earthquakes coincide with normal faulting at divergent boundaries and with strike-slip faulting at transform boundaries.
Deep-ocean trench (convergence) Lithosphere Lithosphere Asthenosphere
Deep-ocean trench (convergence) Lithosphere Lithosphere Asthenosphere Large shallow earthquakes occur mainly on thrust faults.
Deep-ocean trench (convergence) Lithosphere Asthenosphere Large shallow earthquakes occur mainly on thrust faults. Intermediate- and deepfocus earthquakes occur in the descending slab.
Earthquakes indicate how tectonic plates interact at their boundaries Which kinds of plate-tectonic boundaries are associated with earthquake activity? A. Transform only B. Convergent only C. Divergent only D. Transform and convergent only E. Convergent, divergent and transform
Earthquakes indicate how tectonic plates interact at their boundaries Which kinds of plate-tectonic boundaries are associated with earthquake activity? A. Transform only B. Convergent only C. Divergent only D. Transform and convergent only E. Convergent, divergent and transform
Earthquakes indicate how tectonic plates interact at their boundaries In which plate-tectonic environment do earthquakes occur at the greatest depths? A. Transforms B. Mid-ocean ridges C. Subduction zones D. Continent-continent collision zones
Earthquakes indicate how tectonic plates interact at their boundaries In which plate-tectonic environment do earthquakes occur at the greatest depths? A. Transforms B. Mid-ocean ridges C. Subduction zones D. Continent-continent collision zones
Earthquakes indicate how tectonic plates interact at their boundaries What kind of faulting most commonly occurs at midocean ridges? A. Normal B. Reverse C. Thrust D. Strike-slip
Earthquakes indicate how tectonic plates interact at their boundaries What kind of faulting most commonly occurs at midocean ridges? A. Normal B. Reverse C. Thrust D. Strike-slip
Earthquake Sounds Click video to begin playing
Earthquake Sounds T waves are seismic waves that travel through: A. The crust B. The mantle C. Seafloor sediments D. Water
Earthquake Sounds T waves are seismic waves that travel through: A. The crust B. The mantle C. Seafloor sediments D. Water
Earthquake Sounds True or False: The Indian Ocean tsunami of 2004 was caused by a relatively small-magnitude, long-duration earthquake that displaced a 100-km-long fault system. A. True B. False
Earthquake Sounds True or False: The Indian Ocean tsunami of 2004 was caused by a relatively small-magnitude, long-duration earthquake that displaced a 100-km-long fault system. A. True B. False
Earthquake Sounds Which plate-tectonic environment generated the faulting that caused the 2004 Indian Ocean tsunami? A. Mid-ocean ridge B. Oceanic Transform C. Subduction zone D. None of these
Earthquake Sounds Which plate-tectonic environment generated the faulting that caused the 2004 Indian Ocean tsunami? A. Mid-ocean ridge B. Oceanic Transform C. Subduction zone D. None of these
Earthquake Sounds What style of faulting led to the 2004 Indian Ocean tsunami? A. Thrust B. Normal C. Reverse D. Strike-slip
Earthquake Sounds What style of faulting led to the 2004 Indian Ocean tsunami? A. Thrust B. Normal C. Reverse D. Strike-slip
Normal Fault During normal faulting, the hanging wall moves the footwall. A. over B. down C. horizontally with respect to D. none of these
Normal Fault During normal faulting, the hanging wall moves the footwall. A. over B. down C. horizontally with respect to D. none of these
Normal Fault If you properly recognize a normal fault in the landscape, what type of tectonic stress must have been present to cause it? A. compressional B. tensional C. shear
Normal Fault If you properly recognize a normal fault in the landscape, what type of tectonic stress must have been present to cause it? A. compressional B. tensional C. shear
Normal Fault The focus of an earthquake is always located: A. at the surface B. in the mantle C. along the fault plane D. above the epicenter
Normal Fault The focus of an earthquake is always located: A. at the surface B. in the mantle C. along the fault plane D. above the epicenter
Normal Fault An earthquake generates three groups of waves when a fault is initiated; which will reach you first? Which will do the most damage? A. P waves; S waves B. S waves; surface waves C. surface waves; S waves D. P waves; surface waves
Normal Fault An earthquake generates three groups of waves when a fault is initiated; which will reach you first? Which will do the most damage? A. P waves; S waves B. S waves; surface waves C. surface waves; S waves D. P waves; surface waves
Normal Fault If you approach an outcrop where a fault is evident in cross section, what must be present in order for you to determine whether of not the movement is normal or reverse? A. a marker bed B. a seismograph C. fossils D. your geology professor
Normal Fault If you approach an outcrop where a fault is evident in cross section, what must be present in order for you to determine whether of not the movement is normal or reverse? A. a marker bed B. a seismograph C. fossils D. your geology professor
Reverse Fault During reverse faulting, the hanging wall moves the footwall. A. over B. down C. horizontally with respect to D. none of these
Reverse Fault During reverse faulting, the hanging wall moves the footwall. A. over B. down C. horizontally with respect to D. none of these
Reverse Fault If you properly recognize a reverse fault in the landscape, what type of tectonic stress must have been present to cause it? A. compressional B. tensional C. shear
Reverse Fault If you properly recognize a reverse fault in the landscape, what type of tectonic stress must have been present to cause it? A. compressional B. tensional C. shear
Reverse Fault The epicenter of an earthquake is always located: A. at the Earth s surface, directly above the focus B. in the mantle C. along the fault plane D. on the fault scarp
Reverse Fault The epicenter of an earthquake is always located: A. at the Earth s surface, directly above the focus B. in the mantle C. along the fault plane D. on the fault scarp
Reverse Fault An earthquake generates three groups of waves when a fault is initiated; which wave type does not pass through liquids? A. P waves B. S waves C. surface waves D. water waves
Reverse Fault An earthquake generates three groups of waves when a fault is initiated; which wave type does not pass through liquids? A. P waves B. S waves C. surface waves D. water waves
Reverse Fault Displacement along a reverse fault is: A. the Richter magnitude of the earthquake B. a measurement of the relative offset along the fault plane C. a measurable distance between the focus and epicenter of an earthquake D. always in the same direction as that of a normal fault
Reverse Fault Displacement along a reverse fault is: A. the Richter magnitude of the earthquake B. a measurement of the relative offset along the fault plane C. a measurable distance between the focus and epicenter of an earthquake D. always in the same direction as that of a normal fault
P and S waves After an earthquake releases energy, which type of wave will arrive first? A. P wave B. S wave C. surface waves D. tsunami wave
P and S waves After an earthquake releases energy, which type of wave will arrive first? A. P wave B. S wave C. surface waves D. tsunami wave
P and S waves Which direction does matter move with respect to energy in a P wave? A. parallel B. perpendicular C. oblique D. none of these
P and S waves Which direction does matter move with respect to energy in a P wave? A. parallel B. perpendicular C. oblique D. none of these
P and S waves Which direction does energy move with respect to matter in an S wave? A. parallel B. perpendicular C. oblique D. none of these
P and S waves Which direction does energy move with respect to matter in an S wave? A. parallel B. perpendicular C. oblique D. none of these