Chapter 6 - Section 3 - Monitoring Earthquakes

Question 1

What is a seismogram?

Answer 1

The record of an earthquake’s seismic waves produced by a seismograph.

Question 2

How does a seismograph record seismic waves?

Answer 2

A simple seismograph can consist of a heavy weight attached to a frame by a spring or wire. A pen connected to the weight rests its point on a drum that can rotate. As the drum rotates slowly, the pen draws a straight line on paper wrapped tightly around the drum. Seismic waves cause the seismograph’s drum to vibrate. But the suspended weight with the pen attached moves very little. Therefore, the pen stays in place and records the drum’s vibrations.

Question 3

What four instruments are used to monitor faults?

Answer 3

tiltmeters

creep meters

laser-ranging devices

GPS Satellites

Question 4

What changes do tiltmeters measure?

Answer 4

tilting or raising of the ground

Question 5

What changes do creep meters measure?

Answer 5

horizontal movement on the ground

Question 6

What do laser-ranging devices measure?

Answer 6

horizontal fault movement

Question 7

What do GPS satellites measure?

Answer 7

changes in elevation and horizontal movement along faults

Question 8

What are 3 ways in which geologists use seismographic data?

Answer 8

they use the data to map faults and detect changes along faults.

Geologists are also trying to use these data to develop a method of predicting earthquakes.

Question 9

Why do geologists collect data on friction along the sides of faults?

Answer 9

because How rocks move along a fault depends on how much friction there is between the sides of the fault.

Question 10

What is a seismograph?

Answer 10

device used to measure seismic waves

Question 11

What is friction?

Answer 11

The force that opposes the motion of one surface as it moves across another surface.