Earthquakes - SECONDARY EARTHQUAKE HAZARDS Flashcards

1
Q

primary hazard associated with earthquakes

A

failure of structures

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2
Q

secondary earthquake hazards

A

liquefaction
ground displacement
ground fissures
earthquake-induced mass wasting
fires
tsunamis

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3
Q

what sediment is prone to liquefaction

A

sand

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4
Q

what is liquefaction

A

compacted sand-rich sediments behave like a fluid due to lateral/shear motion

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5
Q

what causes liquefaction

A

lateral motion increasing the water pressure within pore spaces, preventing vibrating grains from making contact with each other

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6
Q

rocks on either side of a fault move away from each other horizontally or vertically

A

ground displacement

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7
Q

are large open cracks that typically develop near the surface

A

ground fissures

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8
Q

ground fissures are developed near the surface where there is little resistance to ______ and _____

A

rolling and stretching motion

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9
Q

t or f: open fissures affect less number of structures than faults

A

F (affect more because they occur over a much broader area)

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10
Q

t or f: earthquake trigger mass wasting

A

t

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11
Q

gas lines are broken and ignited by broken electrical wires in damaged buildings

A

fire

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12
Q

a series of ocean wave that is formed when energy is suddenly released and transferred into the ocean

A

tsunami

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13
Q

tsunamis are triggered usually by _____ faulting

A

thrust

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14
Q

italian seismologist who created an intensity scale

A

Giuseppe Mercalli, 1902

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15
Q

quantifies earthquakes through first-hand human observations of the damage sustained by buildings

A

intensity scale

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16
Q

rankings on intensity scale are _____ and ____ such that similar rankings are grouped together

A

plotted on a map ; contoured

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17
Q

what is PEIS

A

PHIVOLCS Earthquake Intensity Scale

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18
Q

PEIS was developed as a response to what particular event?

A

1990 Luzon Earthquake (Mag 7.8)

19
Q

PEIS replaced what intensity scale on what year?

A

Rossi-Forel intensity scale on 1996

20
Q

one of the first seismic scales used to reflect earthquake intensities and was used for about two decades until the introduction of Mercalli scale

A

Rossi-Forel intensity scale

21
Q

who developed Rossi-Forel intensity scale?

A

Michele Stefano de Rossi and Francois Alphonse Forel in the late 19th century

22
Q

PEIS ranges from

A

I to X

23
Q

PEIS

A

scarcely perceptible
slightly felt
weak
moderately strong
strong
very strong
destructive
very destructive
devastating
completely devastating

24
Q

quantify the amount of ground shaking and energy released of earthquakes

A

Magnitude Scales

25
Q

Richter Magnitude Scale was named after

A

Charles F. Richter

26
Q

Richter magnitude scale rates earthquakes based on _______

A

the size of their seismic waves

27
Q

what measures the size of seismic waves

A

seismograph

28
Q

the size of seismic waves is governed by its:

A

amplitude (wave height) and distance

29
Q

scientists discovered that Richter magnitude scale isn’t always consistent with one another, particularly for ______

A

large-magnitude earthquakes

30
Q

t or f: moment magnitude scale is based on the similar types of seismogram measurements as Richter’s

A

T

31
Q

why is moment magnitude more accurate than richter’s?

A

because it covers a wide range of geological conditions and magnitude

32
Q

the total amount of energy released of earthquake based on moment magnitude scale is determined by:

A

the surface area of the ruptured fault and the vertical/horizontal displacement

33
Q

a magnitude 7 earthquake is how many times stronger than magnitude 4 in terms of ground shaking

A

1000x

34
Q

a magnitude 7 earthquake is how many times stronger than magnitude 4 in terms of energy released

A

27,000x

35
Q

san francisco earthquake

A

1906, Mag 7.8

36
Q

loma prieta earthquake

A

October 17, 1989 (Mag 6.9)

37
Q

indonesian earthquake

A

December 24, 2004 (Mag 9.1)

38
Q

classification of earthquakes based on magnitude

A

great 8 or more
major 7-7.9
strong 6-6.9
moderate 5-5.9
light 4-4.9
minor 2-3.9
micro 1.0-1.9

39
Q

Abra earthquake

A

July 27, 2022 (Mag 7.0)

40
Q

in terms of frequency _____ to _____ types of earthquake magnitude often occur

A

micro to minor

41
Q

Moro Gulf Earthquake

A

August 17, 1976
Mag 8.1
depth: 59km
along cotabato, near sulu trench
12:11 AM
generated a 4.5 km tsunami

42
Q

Japan earthquake that caused liquefaction

A

Niigata, Japan (1964)
magnitude 7.5

43
Q

Taiwan earthquake

A

1999 , Mag 7.6