Earthquakes
false, movement along breaks in Earth's lithosphere
Earthquakes are vibrations in the ground that result from severe storms. True or false
plate boundaries
Earthquakes most frequently take place along _______________________________________.
secondary waves
S waves
changes in seismic waves
Scientists discovered changes in Earth's interior by studying ____________________________.
false, perpendicular to the direction that waves travel
Secondary seismic waves cause rocks to vibrate in the same direction waves travel. true or false
stop
Secondary waves _____________________ when they hit the liquid outer core.
Richter scale
Seismologists use the ________________________________ to describe the magnitude of earthquakes.
Modified Mercalli Scale
"We all got scared and ran outside. The house was ok, but our old shed fell over." This quote would help a researcher to place an earthquake on which scale?
magnitude
An earthquake with a(n) ___________________________________ of 7.2 releases about 30 times as much energy as an earthquake as an that registers 6.2 on the Richter scale.
three
At least __________________ seismographs are needed to accurately locate an earthquake epicenter.
1000 times
For the Richter scale, each increase on the scale represents ten times the amount of ground motion recorded on the seismogram. How much more motion is there for a magnitude 7 earthquake than a magnitude 4 earthquake?
27,000 times
For the moment magnitude scale, each increase on the scale represents 31.5 times more energy released by the earthquake. Which is a good estimate of about how much more motion is there for a magnitude 7 earthquake than a magnitude 4 earthquake?
Great Lakes Region
If you wanted to avoid earthquakes, which would be the best choice of location- West coast, southern Alaska, largest island in Hawaii, the Great Lakes region
false- in the oceans or on edges of continents
Most earthquakes occur in the centers of continents. True or false
surface waves
Most of the destruction during an earthquake is caused by_____________________________________.
primary waves
P waves
seismologists
People who study earthquakes are called?
slow down
Primary waves____________________________ when they hit the liquid outer core.
false- Richter
The Modified Mercalli scale uses the amount of ground motion at a given distance from an Earthquake to determine magnitude. True or false
seismograph
The Richter scale is based on the height of the lines traced by ___________________________________.
primary
The _____________________ waves are the first to reach a seismograph after an Earthquake.
farther away
The farther apart primary, secondary, and surface waves are, the ________________________________- the epicenter is.
False, larger
The larger the force applied to a fault, the smaller the chance of a large earthquake. True or false
surface waves
The most destructive seismic waves are ______________________________.
focus
The point in Earth's interior where the energy release of an earthquake occurs in the ____________________________.
epicenter
The radius of the circle seismologists draw on a map is equal to the distance from a station to an earthquake's ______________________.
surface waves
The slowest seismic waves are ___________________________________.
epicenter
To locate an earthquake's _____________________, scientist use information from three seismograph stations.
temperature, chemistry of the rocks, pressure
What factors effect the speed of a seismic wave?
Modified Mercalli Scale
What scale would be used to classify an earthquake based on a description found in ancient writings?
p waves
Which waves travel the deepest into the center of the Earth?
primary
_____________________________ waves arrive at a seismograph station first.
secondary waves
_________________________________ move through Earth by causing particles in rocks to move at right angles to the direction of the waves.
primary waves
_________________________________ move through the Earth by causing particles of rocks to move back and forth in the same direction as the waves.
seismograms
graphical illustration of earthquake waves
seismometer
instruments that record seismic activity
moment magnitude scale
used to describe the amount of energy an earthquake releases
surface waves
waves that travel outward from the epicenter
