Chapter 05: Earthquakes (Ch 11) Flashcards Preview

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Flashcards in Chapter 05: Earthquakes (Ch 11) Deck (15)
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1
Q

Earthquakes

A

Ground shaking caused by sudden movement of rock sliding past rock

Most occur near pre-existing faults

2
Q

Faults

A

Fractures in the Earth’s crust; when active, slippage of the rocks located along faults causes earthquakes

3
Q

Hypocenter/focus

A

Subsurface origin of earthquake

4
Q

Epicenter

A

Surface location directly above hypocenter/focus

5
Q

Causes of weak earthquakes (5)

A

Landslides
Meteorites
Dams
Deep well injection (waste injection, fracking)
Volcanic eruptions

6
Q

Cause of strong earthquakes

A

Stress builds up from plate movement

Eventually, stress overcomes frictional resistance

Movement occurs as rocks break

7
Q

Elastic rebound

A

The “snapping back” of the rock

8
Q

Foreshocks and aftershocks

A

“Minor” earthquakes that occur before and after major earthquake

Rocks are either preparing to break or adjusting after breaking

Both can occur for years

9
Q

San Andreas Fault System

A

North American & Pacific plate boundary (transform/strike-slip)

Big earthquake every ~100 years

10
Q

P waves (primary waves)

A

Type of body wave

The first wave of vibrations felt

Travels faster than S waves

Travel through solids, liquids, and gases

Motion: slinky-like (lateral wave movement)

11
Q

S waves (secondary waves)

A

Type of body wave

Felt after P waves (move slower than P waves)

Greater amplitude than P waves

Complex/slow motion (think: rope being shaken; up-down movement)

12
Q

Surface waves

A

Last to arrive (after P and S waves)

These cause the most property damage

13
Q

Liquefaction

A

Saturated or partially saturated soil substantially loses strength/stiffness in response to stress/vibrations, causing it to behave like a liquid

14
Q

Tsunami

A

Caused by earthquake, submarine landslide, or other disturbance

15
Q

New Madrid seismic zone

A

Middle of North American plate (Missouri, Arkansas, Kentucky, Tennessee)

Anomolous because in the middle of a plate

Two possibilities: plate getting ready to split apart, or aftershocks from Pangaea forming