Earthquake

Question 1

The three basic types of stress that causes deformation in rocks

Answer 1

Compression
Tension
Shear

Question 2

Rocks near the surface of the earth are ______

Answer 2

elastic

Question 3

when a force (stress) that is acting on them is removed, the rocks will:

Answer 3

return to their original shape

Question 4

All elastic materials have an _________________, which is the point in which they no longer behave elastically and deformation becomes
permanent.

Answer 4

Elastic Limit

Question 5

Difference between fractures and faults

Answer 5

All faults involve some type of slippage or movement, whereas
fractures do not.

Question 6

Seismic waves generated by earthquakes and human made explosions will ________ and _________ when encountering layers of different density.

Answer 6

reflect and refract

Question 7

He is a Scottish geologist who authored the The Dynamics of Faulting and Dyke Formation with Application to Britain (Edinburgh, 1942, 1951) and systematized our knowledge of the geometry and stress fields of various faults. He contended that the direction of the maximum principal stress along normal faults is ________.

A. Ernest Masson Anderson; vertical
B. John Graham Ramsay; vertical
C. Charles Lyell; horizontal inward
D. James Hutton; diagonal

Answer 7

A. Ernest Masson Anderson; vertical

Question 8

refers to vibrational waves that travel through solid earth
materials which may be magmatic, tectonic, or artificial in origin

Answer 8

Seismic Waves

Question 9

Seismic waves are divided into two parts, which are:

Answer 9

Body Waves and Surface Waves

Question 10

compressional waves; parallel to direction the wave is travelling, causing rocks to alternately compress and decompress as successive waves pass through

Answer 10

P waves

Question 11

transverse/perpendicular to direction of wave propagation

Answer 11

S waves

Question 12

P waves travel at the speed of _________ km/sec

Answer 12

4 to 7 km/sec

Question 13

S waves travel at speeds of _________ km/sec

Answer 13

2 to 5 km/sec

Question 14

What is the main difference between a P wave from an S wave?

Answer 14

P waves can pass through solid and liquid materials, While S waves cannot pass through liquids..

Question 15

It is the instrument used to detect seismic waves. A heavy suspended mass is held as motionless as possible, suspended by springs or hanging it as a pendulum. When the ground moves, the frame of the instrument moves with it.

Answer 15

Seismometer

Question 16

It is a seismometer with a recording device that produces a permanent record of earth motion, usually in the form of wiggly line drawn on a moving strip of paper.

Answer 16

Seismograph

Question 16

It is the paper record of earth vibration. The different waves travel at different rates, so they arrive at seismograph stations in a definite order: first P waves, then S waves, and finally, the surface waves.

Answer 16

Seismogram

Question 17

What factor is used to calculate the distance of the seismograph station from the earthquake source?

Answer 17

The interval of arrival between S and P waves

Question 18

How many seismograph stations are needed to pinpoint the exact location of an earthquake?

Answer 18

At least three seismograph stations

Question 19

How were the major layers of Earth inferred?

Answer 19

Using seismic waves. When seismic waves travel through the Earth, they encounter different materials, which cause them to change speed and direction, inferring that the wave has crossed a new layer beyond the crust.

Question 20

How do Earthquakes occur?

Answer 20

Stresses between / within rocks, tectonic movement

Question 21

Two types of earthquakes

Answer 21

Volcanic and tectonic

Question 22

This theory holds that earthquakes originate when a force (stress) acts on a rock body, causing it to deform and accumulate strain. Eventually the rock reaches its elastic limit, at which point it ruptures or fails suddenly, releasing the strain it had accumulated.

Answer 22

Elastic rebound theory

Question 23

why do earthquakes do not occur deeper than 435 miles (700 km) below the surface?

Answer 23

because the higher temperatures cause the rocks to become so ductile that they deform only by plastic flow, hence do not rupture

Question 24

The main cause for loss of life in an earthquake

Answer 24

Structural Failure (man-made structures / buildings)

Question 25

How many died and how strong was the 1976 Tangshan disaster?

Answer 25

250,000 to 650,000 ; 7.5 magnitude

Question 26

True or False: engineers must consider the vertical forces to prepare a building to be resilient to earthquakes

Answer 26

False, the lateral forces must also be taken into account

Question 27

A series of ocean waves that form when energy is suddenly transferred to the water by an earthquake, volcanic eruption, landslide, or asteroid impact.

Answer 27

Tsunami

Question 28

How many ranks are there in the Mercalli Intensity Scale?

Answer 28

12 ranks

Question 29

How much energy is there between one magnitude rank to the next magnitude rank?

Answer 29

tenfold or x^10