nat dis ch3
Usually, the biggest concern in designing buildings to withstand large earthquakes is the ____________ components of movement.
. sideways push from the horizontal
The frequency of a wave is __________________.
. the number of waves passing a given point per unit time
Which of the following buildings would likely be the safest to be located in during an earthquake?
A two-story modern wood frame house
The _________ waves' motion is similar to S waves, except it is from side-to-side in a horizontal plane roughly parallel to Earth's surface.
Love
Seismic waves that travel only near Earth's surface are of two main types: _________ waves.
Love and Rayleigh
_________ waves are transverse waves that propagate by shearing or shaking particles in their path at right angles to the direction of advance.
Love and S
Which of the following is not a way to improve a building's resistance to earthquakes?
Match its period to seismic waves at that location.
The point on Earth's surface directly above the point where the fault first ruptures is called the ____________
epicenter
P waves can travel through ________________.
gases, liquids, and solids
Earthquake-induced ground motions cause buildings to sway at certain periods. In general, the taller the structure, the _______ the period.
longer
Flexible buildings (made of wood or steel) have a ________ resonant period than a stiffer building (one of brick or concrete).
longer
Despite the profound effects that earthquakes have had on civilizations for so many centuries, systematic scientific observations were not made until the early _________ century, when good descriptions were made of earthquake effects on the land.
nineteenth
Faults on which the dominant forces are extensional are recognized by the separation of the pulled-apart rock layers in a zone of omission; these are __________.
normal faults
Steno's law of __________ states that sediment layers are continuous, ending only by butting up against a topographic high, such as a hill or a cliff, by pinching out due to lack of sediment, or by gradational change from one sediment type to another.
original continuity
The law of __________ explains that sediments (such as sand, gravel, and mud) are originally deposited or settled out of water in horizontal layers.
original horizontality
The process of reinforcing existing buildings to increase their resistance to seismic shaking is known as __________.
retrofitting
. ________ faults are commonly found at areas of plate convergence where subduction or continental collision
reverse
With compressional forces, the hanging wall moves upward relative to the footwall; this type of fault is referred to as a __________ fault.
reverse
The strike-slip San Andreas Fault in California is a _______ fault more than 1,300 km long
right-lateral
When most of the movement along a fault is horizontal, the fault is referred to as a __________ fault.
strike-slip
. Earthquakes are most commonly caused by ______________.
sudden earth movements along faults
In the law of ____________, Steno stated that in an undeformed sequence of sedimentary rock layer, each sedimentary rock layer is younger than the bed beneath it, but older than the bed above it.
superposition
Shear walls are designed to
take horizontal forces from the floors and roofs and transmit them to the ground
The Richter scale is set up so that for every _______ increase in the amplitude of the recorded seismic wave, the Richter magnitude increases one number, e.g., from 4 to 5.
ten-fold
The farther away a seismic station is from an earthquake's hypocenter the __________.
the longer the delay is between the arrival of the P waves and S waves
The Lisbon earthquakes of 1755 are historically significant because ______________.
they changed the prevailing philosophies of the era, producing a more pessimistic view of the world
Human-caused and natural events can be distinguished using seismic waves because __________.
they produce different S and P wave patterns
Using the S-P timing method, epicenters can be located using seismograms from a minimum of ______ recording stations.
three
First-order analysis of a seismogram record allows seismologists to do all but which of the following?
to develop a Modified Mercalli Intensity map
Can the same fault be classified as both a strike-slip and a transform fault?
yes
The _____ wave travels fastest and moves in a push-pull fashion of alternating pulses of compression (push) and extension (pull).
P
Velocities for __________ waves in granite are about 5.5 to 6 km/sec, but in water they slow to 1.4 km/sec.
P
The ________ waves advance in a backward-rotating, elliptical motion.
Rayleigh
__________ occurs when a building's period matches period of passing seismic waves.
Resonance
The reduction of ______ waves at the core-mantle boundary indicates that the outer core is mostly liquid.
S
__________ waves travel only through solids; on reaching liquid or gas, the wave energy is reflected back into rock or is converted to another form.
S
A tall office building built on a foundation designed to slide or roll with an earthquake is an example of using __________ to reduce earthquake-induced damage
base isolation
Which of the following wave types travels slowest through rock?
Surface Waves
The seismic moment is calculated by multiplying all but which of the following quantities together?
The Modified Mercalli Intensity at the epicenter
The intensity of an earthquake is influenced by all but which of the following?
The current air pressure
The __________ is measured in cross-sectional view as the angle of inclination from horizontal of a tilted rock layer, and _______ is viewed in map view as the compass bearing of the rock layer where it intersects a horizontal plane.
dip; strike
A normal fault occurs when the hanging wall moves ________ relative to the footwall.
down
In general, during an earthquake you should __________.
drop, cover, and hold on where you currently are
