What are the fastest body waves
p waves = Primary wave
What type of materials can P waves travel through?
solids, liquids, and gases
What type of materials can S waves move through?
only solids
Where does an earthquake first occur?
focus
How does the structure of the Earth's interior affect seismic waves?
It affect the speed and direction of seismic waves.
Why do earthquakes usually occur at plate boundaries?
The rock near the boundaries are under great stress.
What is the epicenter of an earthquake?
the point on the Earth's surface directly above the earthquake's focus
What causes tsunamis?
undersea earthquakes, landslides, volcanic eruptions
Why do fault zones form at plate boundaries?
intense stress occurs there when the plates separate, collide, subduct, or slide past each other
seisomogram
a tracing of earthquake motion that is recorded by a seismograph
How does the height of waves on the seismogram relate to the size of the earthquake?
The higher the lines on a seismogram the larger the earthquake.
seismograph
an instrument that detects and measures the strength of earthquakes
Richter Scale
a scale used to measure the energy released by an earthquake
body wave
a seismic wave that travels through the interior of the earth
surface wave
a seismic wave that travels on the surface of the earth
Given a seismogram, be able to label the P- wave, S - wave, and amplitude.
Given a seismogram, be able to determine the S- P lag time.
Be able to label the focus and epicenter.
What are surface waves?
Earthquake waves that travel along the surface of the earth not through the Earth. These are the last waves to arrive.
Earthquake
sudden strong movements of Earth's crust
Focus
the place in the earth's crust the breaks and move apart
Epicenter
the place on the surface of Earth that is directly above the focus
How is the distance to an earthquake related to how much damage can occur?
The closer an earthquake, the more damage it can cause
seismic waves
another name for earthquake waves
How is the distance to an earthquake related to the S-P lagtime?
The greater the distance to an earthquake, the greater the SP lagtime.
How are the numbers on the Richter Scale related to the strength of an earthquake.
The higher the number, the stronger the earthquake.
What is the most common cause of earthquakes?
Faulting - the pulling or pushing together of parts of the Earth's crust
seismologist
a scientist that studies earthquakes
What is the amount of damage caused by an earthquake dependant upon?
1. strength of earthquake
2. kind of rock or soil it occurs in
3. the population of the area affected
4. kinds of buildings in the area
5. the time at which the earthquake occurs
What are some possible warning signs of earthquakes?
1. changes in the tilt of the Earth's surface
2. land near a fault may rise or sink slightly
3. water levels in wells may change
Be able to read a nomogram.
Be able to use a distance - time graph to determine the distance to an earthquake. Ex. How far away is an earthquake if the S - P lag time is 45 s?
440 km
Be able to locate an earthquake epicenter given the triangulation data.
The epicenter is the common point of intersection of at least 3 sets of seismogram data.
Be able to compare the energy released by different magnitude earthquakes. Ex. How much more energy does magnitude 9 earthquake release than a magnitude 6 earthquake?
9 - 6 = 3
30 x 30 x 30 = 27,000.
A magnitude 9 earthquake releases 27,000 x more energy than a magnitude 6 earthquake.
Using a Modified Mercalli Scale, be able to describe the type of damage experienced during an earthquake.
This scale is based on personal observation of the damage caused by an earthquake.
How is the moment magnitude scale different than the Richter Scale?
It takes into account the amount of slippage , area of slippage, the type of soil / rock in the area, and the duration of the earthquake.
What is elastic rebound?
Elastic rebound occurs when the earth's crust returns to its original undeformed position rapidly after an earthquake.