Chapter 8 Earth Science

1) The elastic rebound theory for the origin of earthquakes was first proposed by ________ following the ________ earthquake. A) Reid; 1906, San Francisco B) Giuseppe; 1925, Pizza Lake C) Richter; 1989, Loma Prieta D) Mohorovicic; 1964, Anchorage

1 2) When an earthquake occurs, energy radiates in all directions from its source. The source is also referred to as the ________. A) inertial point B) epicenter C) focus D) seismic zone

1 3) Which one of the following statements is correct? A) P waves travel through solids; S waves do not. B) P and S waves travel through liquids, but P waves do not travel through solids. C) S waves travel through solids and P waves travel through liquids. D) P and S waves travel through liquids, but S waves do not travel through solids.

1 4) ________ have the highest velocities. A) Primary waves B) Secondary waves C) Surface waves D) Refracted S waves

1 5) Which one of the following is true regarding tsunamis? A) They travel as deep-water waves at speeds greater than surface seismic waves but slower than S waves. B) Their wave heights decrease and wavelengths increase as they move into shallower water. C) They are started by fault-induced, horizontal shifts in the seafloor that suddenly propel great masses of water in opposite directions. D) They occur in the open ocean, wavelengths are many miles or kilometers and wave heights are only a few feet.

1 6) The amount of destruction caused by earthquake vibrations is affected by ________. A) design of structures B) intensity and duration of the vibrations C) nature of the surface material D) all of these

1 7) On a typical seismogram, ________ will show the highest amplitudes. A) P waves B) S waves C) surface waves D) body waves

1 8) Major earthquakes are often followed by somewhat smaller events known as ________. A) aftershocks B) foreshocks C) tremors D) hyposhocks

1 9) The ________ magnitude scale is a measure of the energy released. It does not directly measure the extent of building damage. A) Gutenberg B) Reid C) Mercalli D) Richter

1 10) The instrument that records earthquake events is termed a ________. A) polygraph B) thermograph C) seismograph D) barograph

1 11) ________ is the maximum possible damage designation on the Mercalli scale. A) XII B) 12 C) X D) 10

1 12) The position on Earth's surface directly above the earthquake source is called the ________. A) epicenter B) inertial point C) focus D) seismic zone

1 13) The mechanism by which rocks store and eventually release energy in the form of an earthquake is termed ________. A) elastic rebound B) seismic rebound C) fault displacement D) stress fracture

1 14) Overall, this type of seismic wave is the most destructive. A) P wave B) S wave C) surface wave D) tsunami

1 15) Approximately how much more energy is released in a 6.5 Richter magnitude earthquake than in one with magnitude 5.5? A) 3000 times B) 3 times C) 300 times D) 30 times

1 16) P waves ________. A) propagate only in solids B) are faster than S waves and surface waves C) have higher amplitudes than do S waves D) produce the strongest ground shaking

1 17) The Mercalli Scale is a scale from ________. A) 1 to 12 that rates the energy required for faulting to occur B) 1 to 10 that rates the energy released by an earthquake C) I to XII that rates the structural damage due to an earthquake D) I to X that rates the total energy released during the main quake and all aftershocks

1 18) The distance between a seismological recording station and the earthquake source is determined from the ________. A) earthquake magnitude B) intensity of the earthquake C) length of the seismic record D) arrival times of P and S waves

1 19) The Richter magnitude of an earthquake is determined from the ________. A) duration of the earthquake B) intensity of the earthquake C) arrival time of P and S waves D) amplitude of the surface waves

1 20) Which one of the following best characterizes tsunamis? A) They cause the land to ripple and oscillate. B) They are faster than seismic surface waves. C) They have relatively small amplitudes compared to their very long wavelengths. D) They are easily seen at sea but are lost in the swell and breaking waves along a coast.

1 21) The ________ earthquake was accompanied by extensive fire damage. A) Anchorage, 1964 B) San Francisco, 1906 C) Mexico City, 1985 D) Yerevan, Armenia, 1988

1 22) ________ refers to the tendency for a foundation material to lose its internal cohesion and fail mechanically during earthquake shaking. A) Slurrying B) Liquefaction C) Motion slip D) Seismoflowage

1 23) The record of an earthquake obtained from a seismic instrument is a(n) ________. A) seismograph B) seismogram C) time-travel graph D) epigraph

1 24) Most of our knowledge about Earth's interior comes from ________. A) drill holes B) volcanic eruptions C) seismic waves D) examination of deep mine shafts

1 25) Which one of the following statements about the crust is NOT true? A) It is the thinnest of the major subdivisions. B) It is thickest where prominent mountains exist. C) Oceanic crust is enriched in potassium, sodium, and silicon. D) Continental rocks are compositionally different than oceanic rocks.

1 26) The dense core of Earth is thought to consist predominantly of ________. A) nickel B) lead C) iron D) copper

1 27) The lithosphere is defined as ________. A) a rocky layer having a relatively uniform chemical composition B) a rigid layer of crustal and mantle material C) a rocky layer composed mainly of crustal rocks D) a plastic layer composed mainly of mantle material

1 28) The average composition of the oceanic crust is thought to approximate that of ________. A) granite B) basalt C) peridotite D) iron

1 29) The average composition of the continental crust most closely approximates that of ________. A) granite B) basalt C) peridotite D) iron

1 30) The Earth's magnetic field originates by ________. A) weak electrical currents associated with hot, rising, mantle plumes B) magnetic mineral grains in the inner core C) weak electrical currents associated with fluid motions in the outer core D) magnetization of oxygen and nitrogen atoms in the atmospheric ozone layer by solar radiation

1 31) The asthenosphere is located ________. A) within the crust B) in the upper mantle C) between the mantle and outer core D) within the outer core

38) S waves can travel through solid and liquid media.

39) The time between the first P-wave and S-wave arrivals is a measure of the distance from a receiving station to the epicenter of the earthquake.

40) Earthquakes result from the sudden release of elastic strain energy previously stored in rocks surrounding a zone of fault movement.

41) Tsunamis are caused by sudden displacement of large volumes of seawater.

1 42) The Richter earthquake magnitude scale is based on the total amount of energy released by the earthquake.

1 43) The epicenter of an earthquake is on the surface of the Earth directly above the focus.

1 44) Unconsolidated, water-saturated soils or sediments provide good foundation materials for buildings and other structures.

1 45) Oceanic crust is mainly basaltic in composition; the mantle is more like the igneous rock peridotite in chemical composition.

1 46) Continental crust is generally thicker than oceanic crust.

1 47) The crust and mantle are solids; the inner core is thought to be solid.

1 48) The mantle is composed mainly of metallic iron with small amounts of magnesium silicate minerals.

1 49) What instrument is used to record earthquake vibrations?

1 50) ________ is the name of the earthquake-magnitude scale based on the amount of seismic energy released during the event.

1 51) ________ is another name commonly used by scientists to denote seismic sea waves induced by earthquakes.

1 52) An earthquake of magnitude 7.5 releases about how much more energy than one of magnitude 5.5?

2 53) The ________ is the site of initial rupturing associated with an earthquake.

1 54) What is thought to be the material state (liquid, solid, gas) and elemental composition of Earth's outer core?

1 55) ________ is the cool, brittle, outer layer of Earth that includes the crust and uppermost mantle.

1 56) ________ is the layer of warm rock below the crust and uppermost mantle that readily deforms and flows plastically.

1 57) The ________ core is probably solidified.

1 58) The upper mantle is very close in chemical and mineralogical composition to ________.