Exam 7: Earthquakes

Surface seismic waves originate at the epicenter of an earthquake.

A series of earthquakes that occurred near _____ in 1811-1812 were the most widely felt earthquakes to occur in recorded history.

A(n)_____ is a trembling or shaking of the ground caused by the sudden release of energy stored in rocks beneath the Earth's surface.

The elastic rebound theory involves the sudden release of progressively stored energy in rocks.

Deep rocks behave as _____ material under stress rather than breaking.

As a dense oceanic plate begins to bend down into a trench,it stresses slightly at the top of the bend and normal faults occur.

In the elastic rebound theory,earthquakes are caused by the sudden release of progressively stored _____ in rocks.

The time interval between the first arrival of a P-wave and the first arrival of an S-wave increases with distance from the focus of an earthquake.

On the modified mercalli intensity scale the maximum value is _______.

____ are seismic waves that travel through the Earth's interior,spreading out from the focus in all directions.

Although large earthquakes are rare in the central and eastern United States,when they do occur they tend to be very destructive because _______.

A ____ plots seismic-wave arrival time against distance.

The paper record of an earthquake is a ____.

_____ waves tend to be incredibly destructive to buildings because they produce much ground movement and take a long time to pass.

Both P-waves and S-waves can pass through ____.

The __,the distance between the epicenter and focus,for earthquakes is about 670 km.

Tsunami waves may move faster than ____.

During an earthquake,buildings built on hard rock are damaged more than buildings built on soft sediment.

____ are earthquake waves that cause the most property damage.

The Modified Mercalli Scale determines earthquake intensity,a measure of an earthquake's effect on people and buildings.