Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Geohazard > Earthquakes > Flashcards

Earthquakes Flashcards

1
Q

What is compression?

A

Pushes on rocks from opposite directions which causes rocks to be shortened parallel to the stress applied

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is tension?

A

Pulls rocks from opposite directions, resulting it to become stretched/lengthened

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is shear?

A

Occurs when rocks are being pushed in an uneven manner, causing the rocks to be skewed such that different sides of a rock body slide or move in opposite directions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Rocks near the surface of the earth are __________.

A

elastic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is elastic limit?

A

The point in which they no longer behave elastically and deformation becomes permanent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

TRUE or FALSE. When a force that is acting on the elastic rock is removed, the rocks will not return to their original shape

A

FALSE. it will return to its original shape.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

When rocks deform they often slide past one another along a fracture plane, at which point the fracture is called a ______.

A

FAULT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

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

A

TRUE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What type of fault is the North Bohol Fault?

A

Reverse Fault with minor right and left lateral displacement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where and when does Digdig fault rupture? And what is the surface wave magnitude

A
  • Dingalan Aurora to Kayapa Nueva Vizcaya
  • July 16, 1990
  • 7.8
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

He is a Scottish geologist who authored the T he 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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is sigma 1, 2, and 3 means?

A

maximum, intermediate, and minimum stress

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

TRUE or FALSE. In theory, all faults have no rotational component because displacement even in a dip-slip fault varies along the fault length.

A

FALSE. Have a rotational component

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is seismic waves?

A

refer to vibrational waves that travel through solid earth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is Body waves?

A

travel trough the earth’s interior, spreading outward from the hypocenter in all directions (like sound in air).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the two types of Body wave?

A

Primary and Secondary Waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is primary waves?

A
  • Compressional waves
  • Parallel to direction the wave is travelling, causing rocks to alternately compress and decompress as successive waves pass through
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is secondary waves?

A
  • transverse/perpendicular to direction of wave
    propagation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is surface wave?

A
  • travel on the earth’s surface away from the epicenter
    (like ripples on water)
  • slowest wave (typically at a speed that is 10% slower than S waves)
  • can cause more property damage compared to body waves.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is rayleigh waves?

A
  • ground roll (similar to rolling waves of ocean)
  • move vertically and horizontally
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is love waves?

A
  • Move the ground from side to side in a horizontal plane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Difference between P-wave and S-wave

A

P-wave
- speed is 4 to 7 km/sec
- first wave to arrive at a station
- can pass through solid and liquid

S-wave
-slow, 2-5km/sec
-arrives at a later time than P-wave does
-can pass through solid but not liquid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

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.

A

Seismometer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

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.

A

Seismograph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

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.

A

Seismogram

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How to locate earthquakes?

A
  • The interval of arrival between S and P waves is used to calculate the distance of the seismograph station from the earthquake source.
  • A single station can record only the distance, not the direction to a quake The location of an earthquake is determined by drawing circles on a map (or globe) with the seismograph stations distributed in different parts of the globe.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Range of shallow depth of focus.

A

0-70 km

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Range of intermediate depth of focus.

A

70 - 350 km

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Range of deep depth of focus.

A

350 - 670 km

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

How do earthquakes occur?

A
  • when rocks are subjected to a force, also called stress, they can become deformed or strained.
  • When brittle materials reach their elastic limit they undergo permanent deformation by fracturing
  • ductile materials deform by flowing plastically.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Two types of earthquake.

A

Volcanic and tectonic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

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

A

Elastic Rebound Theory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is epicenter?

A

Located above the hypocenter/focus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is hypocenter/focus?

A

The point where it generally release energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

TRUE or FALSE. Earthquakes occur deeper than 435 miles (700 km) below the surface because the higher temperatures cause the rocks to become so brittle.

A

FALSE. Do not occur deeper than 435 miles (700 km); plastic flow

36
Q

Redistribution of strain commonly produces a series of smaller earthquakes.

A

Aftershocks

37
Q

Primary earthquake sometimes refer to _________.

A

Main shock

38
Q

TRUE or FALSE. Rocks are much stronger under a compressional force compared to a tensional force.

A

TRUE

39
Q

TRUE or FALSE. Convergent boundaries where compressive forces dominate, rocks are able to accumulate less strain before rupturing than at divergent boundaries where tensional forces are dominant .

A

FALSE. more strain

40
Q

What is fault creep?

A

The ability of a rock body to store strain is the frictional resistance of the faults.

41
Q

Based mainly on the knowledge of when and where earthquakes occurred in the past.

A

Long-term Forecasting

42
Q

What are the two aspect of long-term forecasting?

A

Paleoseismology and seismic gap

43
Q

The study of prehistoric earthquakes. Involves the study of offsets in sedimentary layers near fault zones to determine recurrence intervals of major earthquakes prior to historical records.

A

Paleoseismology

44
Q

A zone along a tectonically active area where no earthquakes have occurred recently, but it is known that elastic strain is building in the rocks.

A

Seismic gap

45
Q

Involves monitoring of processes that occur in the vicinity of earthquake prone faults for activity that signify a coming earthquake.

A

Short-term prediction

46
Q

Anomalous events or processes that may precede an earthquake

A

Precursor events

47
Q

Different types of Earthquake precursors

A

Increase in foreshocks
Slight swelling/uplift or tilting of the ground surface
Decreased electrical resistance
Fluctuating water levels in wells
Increased concentration of radon gas in groundwater
Generation of radio signals

48
Q

Reduce the actual amount of shear force that can
develop on the structure.

A

Seismic engineering

49
Q

Different types of seismic engineering.

A

Cross bracing and shear walls
Base isolation
Wrapping of columns with a steel jacket
Spiral wrapping technique on vertical reinforcing rods

50
Q

What type of seismic engineering technique used for outdated buildings?

A

External skeleton and base isolation

51
Q

Examples of Non conventional/Non intrusive methods

A

Microtremor Survey Method
Refraction Microtremor Survey
Horizontal to Vertical Spectral Ratio Method

52
Q

What type of fault is San Andreas Fault?

A

a right lateral (dextral) transform fault that separates the Pacific and North American Plates

53
Q

The network of interlocking faults located on either side.

A

Fault zone

54
Q

TRUE or FALSE. In northern California where the San Andreas fault moves offshore the boundary of the North American plate changes from a transform (shear) setting to one of convergence (compression)

A

TRUE

55
Q

TRUE or FALSE. Subduction zone earthquakes are capable of releasing unusually large amounts of energy is partly due to the way the overriding plate buckles and becomes locked

The surface area over which the slippage or rupture occurs can be quite large compared to that in other plate settings

The descending oceanic plate is relatively cool, which makes the rocks more brittle and capable of accumulating more strain before rupturing

Some of this energy can be transferred to the ocean, creating tsunamis that reach heights of 100 feet 30 m)

A

TRUE

56
Q

Cascadian last major earthquake?

A

1700 or 300 years ago

57
Q

Earthquakes that occur far from a plate boundary or active mountain belt and are generally believed to be related to tectonic forces that are being transmitted through the rigid plates

A

Intraplate earthquake

58
Q

Example of intraplate earthquake

A

New Madrid and Charleston seismic zones because they have a history of producing powerful intraplate earthquakes In 1886 a strong earthquake occurred about 50 miles 80 km) outside of Charleston, South Carolina, causing 60 deaths and extensive property

59
Q

What happened in 1976 Tangshan disaster?

A
  • Intraplate earthquake (Mm. 7.5)
  • people have no memory of large earthquake
  • the 250,000 to 650,000 people perished
60
Q

Walls are usually constructed of brick or stone bound together with mortar, as opposed to reinforced walls with internal supports of wood or steel.

A

unreinforced masonry

61
Q

Once a floor becomes free, it naturally falls onto the one below, which can cause additional floors to fail in a cascading manner

A

pancaking

62
Q

Factors that affect Ground Shaking

A

Period, Natural Vibration Frequency, and Resonance
Focal Depth and Wave Attenuation
Ground Amplification

63
Q

The time (in seconds ) it takes for a building to naturally vibrate back and forth

A

period

64
Q

TRUE or FALSE. Smaller structure take longer time to vibrate back and forth than larger structures.

A

FALSE. Shorter

65
Q

TRUE or FALSE. Period of ground motion is generally controlled by the ground’s stiffness

A

TRUE

66
Q

Refers to the vibration of a structure/building at a fixed frequency; frequency is the number of times the motion is repeated in a set amount of time

A

Natural vibration frequency

67
Q

TRUE or FALSE. As building height increases, the natural
vibration frequency decreases.

A

TRUE

68
Q

When a building’s natural vibration frequency matches the frequency of seismic waves, _________ can occur, causing a building to sway more violently

A

resonance

69
Q

Energy of the resulting seismic waves steadily decreases as they travel away from the focus, a process referred to as _________.

A

wave attenuation

70
Q

TRUE or FALSE. Seismic waves experience different amounts of wave attenuation , depending on the types of geologic materials the waves pass through.

A

TRUE

71
Q

TRUE or FALSE. 1. Loose materials and rocks of lower density will absorb less energy from passing seismic waves compared to rocks that are more rigid and dense

A

FALSE. more energy

72
Q

TRUE or FALSE. 2. On areas of rigid rocks, seismic waves are able to retain less of their energy as they travel farther.

A

FALSE. more of their energy

73
Q

When seismic waves travel through weaker materials, they slow down and lose energy at a faster rate.

A

Ground amplification

74
Q

Secondary earthquake hazards

A

Liquefaction, Ground displacement, ground fissure, earthquake-induced mass wasting, fires, and tsunami

75
Q

Who made the intensity scale?

A

Italian seismologist Giuseppe Mercalli in 1902

76
Q

A seismic scale used and developed by the Philippine Institute of Volcanology and Seismology (PHIVOLCS) to measure the intensity of an earthquake. It was developed as a response to the 1990 Luzon Earthquake

A

Philippine Earthquake Intensity Scale (PEIS)

77
Q

A seismic scale used and developed by the Philippine Institute of Volcanology and Seismology (PHIVOLCS) to measure the intensity of an earthquake. It was developed as a response to the 1990 Luzon Earthquake

A

Philippine Earthquake Intensity Scale (PEIS)

78
Q

Before PEIS what type of intensity scale did we use?

A

Rossi Forel Intensity Scale

79
Q

Quantify the amount of ground motion during an earthquake, and the energy that was released when the rocks ruptured.

A

Magnitude Scales

80
Q

Rates earthquakes based on the size of their seismic waves, as measured by seismographs; governed by amplitude (wave height) and distance

A

Richter Magnitude Scale (named after the seismologist, Charles F. Richter)

81
Q

Based on similar types of seismogram measurements as Richter’s, but is more accurate over a wide range of magnitudes and geologic conditions; based on the total
amount of energy released and is determined by measuring the surface area of the ruptured fault
and how far the land moved along the fault.

A

Moment Magnitude Scale

82
Q

TRUE or FALSE. 10 fold increase in ground motion this corresponds to about a 30 fold increase in energy released at the focus

A

TRUE

83
Q

Classes of magnitude

A

Great 8.0 or more
Major 7.0 - 7.9
Strong 6.0 - 6.9
Moderate 5.0 - 5.9
Light 4.0 - 4.9
Minor 2.0 - 3.9
Microearthquake 1.0 -1.9

84
Q

Moro Gulf Earthquake

A

M w 8.1
Depth: 59 km
Epicenter: 06.3 N, 124.0 E
August 17, 1976 at 12:11 AM
Intensity V in Davao City
Death toll reached up to
3,502 and 1,502 missing

85
Q

Magnitude 6.7 Surigao del Norte Earthquake

A

Magnitude 6.7
February 10, 2017

Geohazard (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions