Volcanoes &Earthquakes

Earthquakes do not occur in the asthenosphere because _____.

• this layer is too hot
• this layer is too rigid
• it is flexible and bends easily when stressed
• all its pressure is slowly released and doesn't build up

A fault is classified by _____.

• the number of earthquakes that occur along it
• the type of plate boundary it occurs along
• the directions in which rocks move along it
• distance that rocks move on either side of the fault
  distance that rocks move on either side of the fault

The first seismic waves to reach a nearby city are _____ waves because they travel the fastest.

• primary
• secondary
• surface
• tertiary

When an earthquake occurs, the _____ waves cause the most damage.

• primary
• secondary
• surface
• tertiary

The point ON Earth’s surface directly above where rocks first start to move is called__________.

• aftershock
• epicenter
• primary wave

The point IN Earth where rocks first start to move is called the__________.

• epicenter
• focus
• primary wave
• aftershock

The instrument that scientists use to record seismic waves is called a(n)

• epicenter scale
• seismic wave gauge
• seismograph
• radio graphic device

Tectonic plates move because of _____.

• convection currents
• lava
• the weight of buildings and people
• weather

The risk of earthquakes is high along the Pacific coast of the United States because_________.

•  no earthquakes erupted there lately & pressure is building
• satellites have detected increasing ground elevation
• it's where the Pacific plate & the NorthAmerican plate meet
• Mountains are being formed

Earthquakes release _____ that has built up in rocks.

• lava
• magnetism
• water
• stress