EARTHQUAKES AND EARTHS INTERIOR Flashcards
What is a shadow zone?
an area in the subsurface of the Earth where seismic waves are not seen
What rock makes up the oceanic crust?
basalt
How can geologists know what the interior of the Earth looks like when we can’t see it?
Geologists use a variety of methods to “see” the interior of the Earth including the study of seismic waves and the magnetic field.
Which peripheral hazard of earthquakes caused the damage shown in the photo?
Landslide
Aftershocks are usually
much weaker than the mainshock.
Which type of wave is a compressional body wave?
P-wave
What rock makes up the oceanic crust?
basalt
Which of the following is a good technique for building safer structures in an earthquake zone?
Use wood-frame construction.
Interpret the travel-time curve shown. Approximately how many minutes elapsed between the arrival of the first P-wave and the arrival of the first S-wave at Station 3?
7
The Earth’s magnetic field is thought to be a direct result of ________.
convection in the outer core.
The locations of major earthquakes
are usually along plate boundaries.
What rock makes up the continental crust?
granite
The inner core is ________.
solid.
What rock makes up the oceanic crust?
basalt
The 2010 Haiti earthquake was so destructive because
of poor construction standards that caused many buildings to collapse.
To find the location of an earthquake’s epicenter, you need to calculate the distance from the epicenter to ____ different seismometer stations.
3
A tsunami
may be just a broad, gentle swelling out at sea but grows as it approaches shore.
The earthquake foci pattern east of Australia and just north of New Zealand indicates which tectonic setting?
Convergent plate boundary
One difference between P- and S-waves is that
only P-waves can travel through a liquid.
When a fault slips and the rock units on either side return to their original shape by generating vibrations, it is called
elastic rebound.
During an earthquake, if the hanging wall slides upward relative to the footwall and if the fault is steep (closer to vertical than horizontal), then the fault is termed a __________ fault. Refer to the following figure for an example of such a feature.
reverse
What kind of waves travel with a compressional motion?
P-waves
On December 26, 2004, a magnitude 9.3 earthquake generated a tsunami that devastated coastlines on the __________ Ocean.
Indian
The Mercalli intensity scale tends to be very subjective and thus is generally only used for historical earthquakes that were near people but were not recorded by seismometers. The Mercalli scale may be considered subjective because it
relies on testimony from people.
S-waves are unable to pass through the Earth’s outer core, which indicates that the outer core is
liquid
The vast majority of earthquakes occur
along all types of plate boundaries.
Generally, which type of earthquake waves travel with the slowest velocity?
surface waves
The Modified Mercalli Scale measures what?
the damage caused by an earthquake
Vertical motion seismographs record earthquakes by producing a squiggly diagram called a
seismogram
The quantity of motion that occurs along a fault is termed
displacement
Earthquakes that occur in a band called the __________ can be used to track the motion of subducted oceanic lithosphere.
Wadati-Benioff zone
A surface along which rock on opposed sides is offset by an earthquake-induced slip is called a
fault
Wet and unconsolidated substrates are uniquely susceptible to __________ during an earthquake.
liquefaction
The spot on the surface directly above where the earthquake occurred is called the what?
epicenter
Long-term prediction methods include(s)
seismic risk assessment.
As a seismologist, you are asked to write a report on the latest earthquake. Your boss want to know the details of the earthquake in terms of damaged caused to the city and surrounding area. In order to get this type of information, which scale would you use?
the Modified Mercalli scale
The RIchter Scale measures what?
the largest jolt of energy caused by an earthquake
Body waves include
both S- and P-waves.
Which of the following does NOT affect the severity of damage from an earthquake?
weather
At any point along the surface of any nonvertical fault, as shown in the following figure, the
hanging wall lies vertically above the footwall.
The moment magnitude is based on the __________ and __________ of the earthquake.
amplitude; displacement
The __________ the earthquake, the LESS severe the damage will be.
farther you are from
Which type of waves are shear waves?
S
Which type of waves are compressional in nature?
P
Earthquakes can often produce __________ by breaking gas lines.
fires
Surface waves
produce most of the damage to buildings during earthquakes.
The point within Earth where an earthquake takes place is termed the
focus
Moderate- and deep-focus earthquakes occur along ONLY
convergent-plate boundaries.
Which tectonic setting has the potential to create the largest earthquakes on Earth?
shallow thrust faults associated with a convergent boundary
