Earthquakes - Final Review Flashcards
Major earthquakes are often followed by somewhat smaller events known as ________.
aftershocks
When an earthquake occurs, energy radiates in all directions from its source. The source is also referred to as the ________.
focus
The position on Earth’s surface directly above the earthquake source is called the ________.
epicenter
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.”
S waves travel through solids and P waves travel through liquids
______ have the highest velocities.
primary waves
On a typical seismogram, ________ will show the highest amplitudes.
surface waves
Overall, this type of seismic wave is the most destructive.
surface waves
P waves ________.
are faster than S waves and surface waves
The distance between a seismological recording station and the earthquake source is determined from the ________.
arrival times of P and S waves
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
Most of our knowledge about Earth’s interior comes from ________.
seismic waves
The lithosphere is defined as ________.
a rigid layer of crustal and mantle material
The average composition of the oceanic crust is thought to approximate that of ________.
basalt
The average composition of the continental crust most closely approximates that of ________.
granite
The asthenosphere is located ________.
in the upper mantle
The point of origin of an earthquake is referred to as the _________.
hypocenter
Which seismic waves arrive first at a seismograph station?
P waves
Most large earthquakes occur__________.
at subduction zones
True or False?
Earthquakes result from the sudden release of elastic strain energy previously stored in rocks surrounding a zone of fault movement.
true
True or False?
S waves can travel through solid and liquid media.
false
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
true
True or False?
The Mercalli earthquake magnitude scale is based on the total amount of energy released by the earthquake.
false
True or False?
Tsunamis are caused by sudden displacement of large volumes of seawater.
true
True or False?
“Unconsolidated, water-saturated soils or sediments provide good foundation materials for buildings and other structures.”
false
True or False?
Continental crust is generally thicker than oceanic crust.
true
True or False?
“The crust, mantle, and outer core are solid.”
false
True or False?
The mantle is composed mainly of metallic iron with small amounts of magnesium silicate minerals.
false
True or False?
Tidal wave is another name commonly used by scientists to denote seismic sea waves induced by earthquakes.
false
True or False?
The outer core is probably solidified.
false
True or False?
Asthenosphere is the layer of warm rock below the crust and uppermost mantle that readily deforms and flows plastically.
true
Three types of faults
Normal - divergent plate boundaries
Reverse - convergent plate boundaries
Strike-slip - transform boundaries
P waves
Come first (primary)
Compressional
Travel through everything
Travel faster than S waves
S waves
Come second (secondary) Oscillating Travel only through solids Slower than P waves Greater amplitude than P waves
Intensity vs Magnitude
Intensity - degree of earth shaking in different areas
Magnitude - energy released at the source
