The elastic rebound theory for the origin of earthquakes was first proposed by ________ following the ________ earthquake.
Reid; 1906, San Francisco
Giuseppe; 1925, Pizza Lake
Richter; 1989, Loma Prieta
Mohorovicic; 1964, Anchorage
When an earthquake occurs, energy radiates in all directions from its source. The source is also referred to as the ________.
Which one of the following statements is correct?
P waves travel through solids; S waves do not.
P and S waves travel through liquids, but P waves do not travel through solids.
S waves travel through solids and P waves travel through liquids.
P and S waves travel through liquids, but S waves do not travel through solids.
________ have the highest velocities
Refracted S waves
Which one of the following is true regarding tsunamis?
They travel as deep-water waves at speeds greater than surface seismic waves but slower than S waves
Their wave heights decrease and wavelengths increase as they move into shallower water
They are started by fault-induced, horizontal shifts in the seafloor that suddenly propel great masses of water in opposite directions.
They occur in the open ocean, wavelengths are many miles or kilometers and wave heights are only a few feet.
The amount of destruction caused by earthquake vibrations is affected by ________.
design of structures
intensity and duration of the vibrations
nature of the surface material
all of these
On a typical seismogram, ________ will show the highest amplitudes.
Major earthquakes are often followed by somewhat smaller events known as ________.
The ________ magnitude scale is a measure of the energy released. It does not directly measure the extent of building damage.
The instrument that records earthquake events is termed a ________.
________ is the maximum possible damage designation on the Mercalli scale.
The position on Earth's surface directly above the earthquake source is called the ________.
The mechanism by which rocks store and eventually release energy in the form of an earthquake is termed ________.
Overall, this type of seismic wave is the most destructive.
Approximately how much more energy is released in a 6.5 Richter magnitude earthquake than in one with magnitude 5.5?
P waves ________.
propagate only in solids
are faster than S waves and surface waves
have higher amplitudes than do S waves
produce the strongest ground shaking
The Mercalli Scale is a scale from ________.
1 to 12 that rates the energy required for faulting to occur
1 to 10 that rates the energy released by an earthquake
I to XII that rates the structural damage due to an earthquake
I to X that rates the total energy released during the main quake and all aftershocks
The distance between a seismological recording station and the earthquake source is determined from the ________.
intensity of the earthquake
length of the seismic record
arrival times of P and S waves
The Richter magnitude of an earthquake is determined from the ________.
duration of the earthquake
arrival time of P and S waves
amplitude of the surface waves
Which one of the following best characterizes tsunamis?
They cause the land to ripple and oscillate.
They are faster than seismic surface waves.
They have relatively small amplitudes compared to their very long wavelengths.
They are easily seen at sea but are lost in the swell and breaking waves along a coast.
The ________ earthquake was accompanied by extensive fire damage.
San Francisco, 1906
Mexico City, 1985
Yerevan, Armenia, 1988
________ refers to the tendency for a foundation material to lose its internal cohesion and fail mechanically during earthquake shaking.
The record of an earthquake obtained from a seismic instrument is a(n) ________.
Most of our knowledge about Earth's interior comes from ________.
examination of deep mine shafts
Which one of the following statements about the crust is NOT true?
It is the thinnest of the major subdivisions
It is thickest where prominent mountains exist.
Oceanic crust is enriched in potassium, sodium, and silicon
Continental rocks are compositionally different than oceanic rocks
The dense core of Earth is thought to consist predominantly of ________.
The lithosphere is defined as ________.
a rocky layer having a relatively uniform chemical composition
a rigid layer of crustal and mantle material
a rocky layer composed mainly of crustal rocks
a plastic layer composed mainly of mantle material
The average composition of the oceanic crust is thought to approximate that of ________.
The average composition of the continental crust most closely approximates that of ________.
The Earth's magnetic field originates by ________.
weak electrical currents associated with hot, rising, mantle plumes
magnetic mineral grains in the inner core
weak electrical currents associated with fluid motions in the outer core
magnetization of oxygen and nitrogen atoms in the atmospheric ozone layer by solar radiation
The asthenosphere is located ________.
within the crust
in the upper mantle
between the mantle and outer core
within the outer core
Choose the option which does not fit the pattern.
Choose the option which does not fit the pattern.
Choose the option which does not fit the pattern
S waves can travel through solid and liquid media.
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.
Earthquakes result from the sudden release of elastic strain energy previously stored in rocks surrounding a zone of fault movement.
Tsunamis are caused by sudden displacement of large volumes of seawater.
The Richter earthquake magnitude scale is based on the total amount of energy released by the earthquake.
The epicenter of an earthquake is on the surface of the Earth directly above the focus.
Unconsolidated, water-saturated soils or sediments provide good foundation materials for buildings and other structures.
Oceanic crust is mainly basaltic in composition; the mantle is more like the igneous rock peridotite in chemical composition.
Continental crust is generally thicker than oceanic crust.
The crust and mantle are solids; the inner core is thought to be solid.
The mantle is composed mainly of metallic iron with small amounts of magnesium silicate minerals.