Chapter 7 Earthquakes Section 1 and 2 What Are Earthquakes?

Question 0

What is a fault?

Answer 0

A fault is a break in Earth’s crust along which blocks of rock slide relative to one another

Question 1

Define earthquake

Answer 1

A movement or trembling of the ground that is caused by sudden release of energy when rocks along a fault move

Question 2

Where do most earthquakes happen?

Answer 2

Most earthquakes take place near the boundaries of tectonic plates

Question 3

Describe earthquakes at divergent boundaries

Answer 3

Plates pull away from one another. Locks drop down. Earthquakes happen along normal faults. example: mid Ocean Ridge.

Question 4

Describe earthquakes at convergent boundaries

Answer 4

Tectonic plates collide. This causes mountain building or subduction. Compression causes the lithosphere to break into fault blocks. Earthquakes happen along reverse faults.

Question 5

Describe earthquakes at transform boundaries

Answer 5

As plates move past each other horizontally, the rocks on both sides of the fault are sheared. Quakes happen at strike-slip faults Schooley at shallow depths.

Question 6

Why do earthquakes happen at transform boundaries?

Answer 6

Rock some both sides of the fault of our broken as they grind past one another

Question 7

What is a fault zone?

Answer 7

Places along plate boundaries when large numbers of interconnected faults are located.

Question 8

What is elastic rebound?

Answer 8

The sudden return of elastically deformed rock to its undeformed shape.

Question 9

What is a seismic wave?

Answer 9

Hey wave of energy that travels through the earth and away from an earthquake in all directions.

Question 10

How does the elastic rebound cause earthquakes?

Answer 10

During the sudden return of elastically deformed rock to its original shape, large amounts of energy are released. This energy travels the rocks of seismic waves. The waves cause the ground to move.

Question 11

What is the other name for a P-wave?

Answer 11

Primary wave because they are always the fastest, and the first waves of an earthquake to be detected.

Question 12

What is an S wave?

Answer 12

An S wave or secondary wave is the second fastest seismic waves. S waves are body waves that sheer rock horizontally from side to side.

Question 13

What are surface waves and why they cause the most damage?

Answer 13

Surface waves can move the ground with the rolling up-and-down motion. Because their energy is focused on earth surface, surface waves tend to cause the most damage.

Question 14

What is a seismometer or seismograph?

Answer 14

Earthquake sensing instruments that record seismic waves

Question 15

What is an earthquake’s focus?

Answer 15

The location within Earth along a fault at which the first motion of an earthquake occurs.

Question 16

What is an epicenter?

Answer 16

The point on Earth’s surface directly above an earthquake starting point or focus

Question 17

What is lag time and why is it important?

Answer 17

The time between the arrival of the P waves and the arrival of the S waves is called lag time and tells scientist how far the waves have traveled.

Question 18

What is triangulation?

Answer 18

A process where at least three seismometer stations are used to calculate the Epicenter up and earthquake.

Question 19

What is magnitude?

Answer 19

Magnitude is the measure of the earthquake’s strength. In the past scientist use the Richter scale. now, they use the moment magnitude scale.

Question 20

What is intensity?

Answer 20

Amount of damage caused by an earthquake.

Question 21

What is the modified Mercalli scale?

Answer 21

A scale used to describe earthquakes intensity. The scale ranges from one to twelve

Question 22

What four factors determine the effect of an earthquake?

Answer 22

Size of the earthquake, distance from the epicenter, local geology, and type of construction

Question 23

How does distance from the epicenter effect in earthquake?

Answer 23

The farther in area is from the epicenter the less destructive earthquake will be

Question 24

How does local geology how to determine that affects of an earthquake on a given area?

Answer 24

Seismic waves are particularly dangerous when they travel through loose soils and sediments that contain large amounts of water.

Question 25

What is liquefaction?

Answer 25

When water saturated soil is shaken by seismic waves the grains the make up the sentiment lose contact with one another and are surrounded by water. This process is called liquefaction.

Question 26

What is earthquake resistant construction?

Answer 26

Wouldn’t steal her more flexible, and flexible structures are more likely to survive shaking. Bricks and concrete are not flexible, and are easily damaged by earthquakes.