## Chapter 10 Earthquakes

 If, during an earthquake, a hanging wall slides upward relative to a footwall, the fault is termed ____________ if the fault is steep (closer to vertical than horizontal).a. reverseb. thrustc. strike slipd. normal a. reverse Which earthquake intensity scale assesses the effects of an earthquake on humans and human-made structures?a. Mercalli scaleb. Richter scalec. seismic-moment magnitude scale a. Mercalli scale The greatest earthquake ever recorded by seismographs occurred in 1960 in Chile and measured ____________ on the seismic-moment magnitude scale.a. 9.0b. 10.0c. 10.5d. 9.5 d. 9.5 Which of these areas of the United States would you expect to have the highest occurance of seismic activity?a. Southeastb. Westc. Centrald. Northeast b. West Faulting and earthquakes are examples of ____________.a. ductile behaviorb. brittle behavior b. brittle behavior Which earthquake severity scale measures the amplitude of deflection of a seismograph pen, standardized to an idealized distance of 100 km between epicenter and seismograph?a. Mercalli scaleb. seismic-moment magnitude scalec. Richter scale c. Richter scale A primary force opposing motion on all faults is ____________.a. gravityb. Van der Waal’s forcec. magnetic attraction among iron-rich mineralsd. friction d. friction Body waves include ____________.a. both S- and P-wavesb. P-waves onlyc. both L- and R-wavesd. both surface and interior waves a. both S- and P-waves Virtually all of the deaths attributed to major earthquakes have resulted from the collapse of buildings.a. falseb. true a. false According to the moment magnitude scale (Mw)—a magnitude 8 earthquake would be 1,000 times greater than a magnitude ____________ earthquake.a. 9b. 4c. 5d. 7 c. 5 Which earthquake severity scale varies from locality to locality for a single earthquake?a. Richter scaleb. seismic-moment magnitude scalec. Mercalli scale c. Mercalli scale The intersection between a fault plane and the ground surface is called the ____________.a. plungeb. seismic interfacec. fault traced. dip line c. fault trace Which earthquake severity scale takes vibration caused only by the S-waves into account when estimating the size of an earthquake?a. seismic-moment magnitude scaleb. Mercalli scalec. Richter scale c. Richter scale What geological setting(s) would you expect to produce seismic activity?a. Rift valleyb. Basinc. Collisional mountain beltd. All of the above are correct d. All of the above are correct Medium- and deep-focus earthquakes occur along ____________.a. convergent-plate boundaries onlyb. divergent-plate boundaries onlyc. transform-plate boundaries onlyd. All of the above are correct. a. convergent-plate boundaries only On December 26, 2004, a magnitude 9 earthquake generated a tsunami that devastated coastlines on the ____________.a. Atlantic Oceanb. Indian Oceanc. Arctic Oceand. Pacific Ocean b. Indian Ocean The quantity of offset that occurs along a fault is termed ____________.a. the fault gaugeb. displacementc. accumulationd. fault gouge b. displacement Long-term prediction of earthquake behavior ____________.a. is based on past earthquake activityb. works on the principle that zones of past seismicity will be active in the futurec. includes the notion of seismic gaps—places where an earthquake is “overdue”d. All of the above are correct. d. All of the above are correct. All discovered faults are likely to experience earthquakes in the next few hundred years.a. falseb. true a. false A surface along which rock on opposed sides is offset by earthquake-induced slip is called a ____________.a. jointb. foldc. walld. fault d. fault Earthquakes that occur in a band called a ____________ can be used to track the motion of subducted oceanic lithosphere.a. Wegener beltb. seismic gapc. Wadati-Benioff zone c. Wadati-Benioff zone How can damage and injury be minimized in areas prone to seismic activity?a. earthquake zoningb. engineering controlsc. warning systemsd. All of the above are correct d. All of the above are correct Earthquake waves that pass through the interior of Earth are termed ____________.a. body wavesb. interior wavesc. R-wavesd. surface waves a. body waves A coiled spring would be useful in illustrating a ____________ wave.a. surfaceb. compressionalc. sheard. body b. compressional An earthquake occurs with an epicenter in the town of New Madrid, Missouri, in the interior of the North American Plate. Where might the hypocenter of this earthquake plausibly be found?a. 20 km beneath New Madridb. 10 km south of New Madridc. in New Madrid (“hypocenter” and “epicenter” mean precisely the same thing)d. 200 km beneath New Madrid … If a fault is nearly vertical in orientation and the two walls of rock on opposite sides slide past one another horizontally, the fault is termed ____________.a. thrustb. normalc. strike slipd. reverse c. strike slip Which type of fault does NOT, by definition, have a fault trace?a. normal faultb. reverse faultc. blind faultd. None of the above are correct; all faults have recognizable traces … Seismic retrofitting is the process of __________.a. strengthening existing buildings and structuresb. mapping areas prone to earthquakesc. predicting earthquakesd. releasing energy a. strengthening existing buildings and structures At any point along the surface of an oblique (nonvertical) fault, the ____________.a. footwall lies to the left of the hanging wallb. hanging wall lies to the left of the footwallc. footwall lies vertically above the hanging walld. hanging wall lies vertically above the footwall d. hanging wall lies vertically above the footwall How many seismic stations are necessary to find the epicenter of an earthquake?a. oneb. fourc. threed. two c. three Aftershocks following a major earthquake ____________.a. may continue for days after the initial earthquakeb. are mostly much smaller than the original earthquakec. may occur on the same fault as the original earthquake, or a different faultd. All of the above are correct d. All of the above are correct Vertical motion seismographs record earthquakes through the production of a squiggly diagram called a ____________.a. wave sheetb. seismogramc. camera lucidad. pictogram b. seismogram Which earthquake severity scale takes into account the type of rock that has been fractured?Select one:a. seismic-moment magnitude scaleb. Mercalli scalec. Richter scale a. seismic-moment magnitude scale Which type of earthquake has the highest velocity?a. L-waveb. R-wavec. P-waved. S-wave c. P-wave The point within Earth where an earthquake takes place is termed the ____________.a. epicenterb. vertexc. eye of the faultd. hypocenter (focus) d. hypocenter (focus) Generally, which type of earthquake waves travel fastest?a. body wavesb. interior wavesc. R-wavesd. surface waves a. body waves Faults that have moved recently or are likely to move in the future are referred to as ____________.a. activeb. reversec. normald. passive a. active Earthquakes are likely to occur along ____________.a. transform-plate boundaries onlyb. divergent-plate boundaries onlyc. All of the above are correct.d. convergent-plate boundaries only c. All of the above are correct. If, during an earthquake, a hanging wall slides upward relative to a footwall, the fault is termed ____________ if the fault is shallow (much closer to horizontal than vertical).a. normalb. reversec. thrustd. strike slip c. thrust A tsunami is ____________.a. an earthquake-generated sea wave that can sometimes destroy coastal cities thousands of kilometers from its sourceb. a sloshing of water back and forth within a lake or bayc. the tendency of wet, clay-rich soils to behave like a liquid during an earthquaked. the amount of change in elevation of local sea level caused by a surging wave a. an earthquake-generated sea wave that can sometimes destroy coastal cities thousands of kilometers from its source Surface waves ____________.a. are the first waves to arrive at a seismograph station after an earthquakeb. produce most of the damage to buildings during earthquakesc. travel more rapidly than body wavesd. are the first waves initially produced in an earthquake b. produce most of the damage to buildings during earthquakes All else being equal, an earthquake that strikes in the eastern United States would produce shaking that would be felt ____________ than one that occurred in the western United States.a. over a lesser distanceb. over the same distancec. over a greater distance c. over a greater distance The point on Earth’s surface directly above the point where an earthquake occurs is termed the ____________.a. epicenterb. eye of the faultc. hypocenter (focus)d. vertex a. epicenter Periods of intermittent sliding on a fault as a result of the release of stress during episodes of displacement, followed by stress buildup to the point that the fault is reactivated is termed ____________.a. stick-slip behaviorb. chaotic faultingc. reverse faultingd. thrust faulting a. stick-slip behavior Sandy substrate is susceptible to ____________ during an earthquake.a. liquifactionb. displacementc. collapsed. faulting a. liquifaction Movement on a fault may occur without generating earthquakes.a. falseb. true b. true Earthquakes are a result of ____________.a. mantle upwellingb. a sudden change in atmospheric pressurec. lithosphere-plate movementd. erosion c. lithosphere-plate movement Short-term predictions of earthquake behavior ____________.a. are primarily based on the behavior patterns of farm animalsb. have been largely unreliablec. are correct approximately 50% of the timed. have saved millions of lives in the past decade alone b. have been largely unreliable If, during an earthquake, a footwall slides upward relative to a hanging wall, the fault is termed ____________.a. reverseb. normalc. thrustd. strike slip b. normal Geologists who specifically study earthquakes are called ____________.a. speleologistsb. paleontologistsc. vulcanologistsd. seismologists d. seismologists