ES Unit 8

What is a fault?

• A place on Earth where earthquakes cannot occur

• a fracture in Earth where movement has occured

• the place on Earth's surface where structures move during an earthquake

• another name for an earthquake

What is an earthquake's epicenter?

• the place on the surface directly above the focus

• a spot halfway between the focus and the surface

• the spot below the focus

• any spot along the nearest fault

Most earthquakes are produced by the rapid release of which kind of energy stored in rock subjected to great forces?

• kinetic

• thermal

• elastic

• mechanical

A seismogram shows that P waves travel

• at the same speeds as surface waves

• more slowly than S waves

• at the same speed as S waves

• faster than S waves

Which of the following is NOT a characteristic of S waves?

• They travel slowly than P waves

• They temporarily change the volume of the material they pass through by compression and expansion

• They shake particles at right angles to their direction of travel

• They cannot be transmitted through air or water

A travel-time graph can be used to find the

• focus of an earthquake

• strength of an earthquake

• damage caused by an earthquake

• epicenter of an earthquake

Where do most earthquakes occur?

• in the mountains of Africa

• around the edge of the Pacific Ocean

• around the edge of the Atlantic Ocean

• on the western lowlands of Europe

An earthquake's magnitude is a measure of the

• size of seismic waves it produces

• amount of shaking it produces

• size of surface waves it produces

• damage it causes

What is the most widely used measurement for earthquakes?

• seismic scale

• Richter scale

• moment magnitude scale

• epicenter magnitude scale

The moment magnitude is calculated using all of the following factors EXCEPT for the

• surface area of a fault

• magnitude of past earthquakes in the area

• average displacement along a fault

• rigidity of rock in the area