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