An earthquake begins 10 km underground; this location is called this.
What is the focus?
Between P-waves and S-waves, these travel faster.
What are P-waves?
A broken gas main after an earthquake can cause this hazard.
What is a fire?
This term describes the amount of movement along a fault.
What is displacement?
An increase of one whole number in magnitude represents about this many times more energy released.
What is 32 times?
A city located directly above where an earthquake begins is at this location.
What is the epicenter?
Between body waves and surface waves, these generally cause more damage.
What are surface waves?
An underwater earthquake that uplifts the seafloor may generate this hazard.
What is a tsunami?
This force resists slipping between surfaces along a fault.
What is friction?
This is the minimum number of seismic stations needed to locate an epicenter.
What is three?
If two blocks of crust slide past each other horizontally, this type of fault is involved.
What is a strike-slip fault?
This scale measures earthquake damage and intensity rather than energy.
What is the Modified Mercalli scale?
Cities with poorly constructed buildings tend to experience greater levels of this during earthquakes.
What is damage?
This is the visual record produced by a seismic instrument.
What is a seismogram?
The Modified Mercalli scale uses this type of numeral system.
What are Roman numerals?
If the hanging wall moves upward, this type of fault is most likely.
What is a reverse fault?
This scale measures the total energy released by an earthquake.
What is the Moment Magnitude (Mw) scale?
Buildings are retrofitted for this main purpose.
What is to reduce damage or prevent collapse?
This term describes the average time between earthquakes on a fault.
What is recurrence interval?
An earthquake of magnitude 8 releases about this many times more energy than a magnitude 7 earthquake.
What is about 32 times?
If water-saturated soil sinks and flows during shaking, this hazard is occurring.
What is liquefaction?
To accurately locate an epicenter, this number of seismic stations is required.
What is three?
Towns farther from an earthquake’s epicenter experience less damage because of this reason.
What is weaker shaking with distance?
This process strengthens older structures against earthquake damage.
What is retrofitting?
An earthquake of magnitude 8 releases about this many times more energy than a magnitude 6 earthquake.
What is about 1,000 times (approximately 1,024)?