quiz 7 Flashcards
Earthquakes that occur in a band called the… of subducted oceanic lithosphere.
can be used to track the motion
Wadati-Benioff zone
On December 26, 2004, a magnitude 9.1 earthquake near Sumatra generated a tsunami that devastated coastlines on the …
Ocean.
indian
The vast majority of earthquakes occur
along passive margins
According to the image below, which seismic wave phase is likely to cause the most damage?
surface wave
Making better
_ is the best way to try to prevent earthquake damage.
building and infrastructure
Which seismic wave phase causes the ground to roll (surface moving up and down) somewhat like a wave on water?
raleigh wave
The… the earthquake, the less severe the damage will be.
farther you are from
The seismic moment is defined as
fault area x average slip over that area x resistance to slip or friction
According to the moment magnitude scale (Mw), a magnitude 8 earthquake releases about 1,000 times as much seismic strain energy as a magnitude … earthquake.
6
The point within Earth where an earthquake first breaks is termed the
focus
Long-term earthquake prediction relies on
seismic risk assessment
Which of the following is NOT true concerning the long-term forecasting of earthquakes? Long-term “forecasting”:
-works on the principle that zones of past seismicity will be active in the future
-includes the notion of seismic gaps-places where an earthquake is overdue
- is based on past earthquake activity
- is not possible
is not possible
Body waves include
both S- and P-waves
Periods of intermittent sliding on a fault because of stress release during episodes of slip, followed by stress buildup to the point that the fault is reactivated, is termed
stick-slip behavior
what does NOT directly affect the severity of damage from an earthquake?
weather
The quantity of motion that occurs along a fault is termed
displacement/slip
the larger the … of the surface constrained waves, the most severe the damage will be
amplitude
Earthquake __
is a means of deciding where the ground is stable enough to build on in earthquake-prone areas.
zoning incorporated into construction codes for an area
a tsunami
a sea wave generated by a displacement of water
surface waves ….
produce most of the damage to buildings during earthquakes
Seismic retrofitting is the process of
making existing buildings and structures less vulnerable to ground shaking
Why do subduction zones have the potential to create the largest earthquakes on Earth?
Subduction zones have very large areas for potential rupture and thus can
produce large earthquakes.
A surface along which rock on opposed sides is offset by an earthquake-induced slip is called a
fault
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…
fault.
strike-slip
Deep-focus earthquakes occur along only
convergent-plate boundaries
Each unit step in the Moment Magnitude scale, Mw
corresponds to an increase in energy released by a factor of 32
Which earthquake scale is used to assess the local effects of an earthquake on humans and human-made structures?
Mercalli scale
At any point along the surface of any nonvertical fault such as is shown in the figure below, the …
hanging wall lies vertically above the footwall
A seismograph records an earthquake which shows a 10-minute interval between the P-wave arrival and the S-wave arrival. How far away from the seismograph station did this earthquake occur?
about 7800 kilometres
…. occurs) when earthquakes causes pore pressure to increase, which in turn causes grains in sands and soils to separate and compact.
liquefaction
