WPR 2 Vocab

Question 0

interplate boundary

Answer 0

earthquake at boundary of 2 plates

Question 1

elastic rebound theory

Answer 1

rocks on either side of fault bending or deforming instead of slipping. continue until slip and straighten out, releasing energy

Question 2

intraplate boundary

Answer 2

earthquake at the interior of a plate

Question 3

convergent boundary

Answer 3

tectonic plate boundary along 2 plates. comes together by subduction (one goes under other, lighter goes over) or collision
force = compression
depth = 400km deep
magnitude = highest

Question 4

divergent boundary

Answer 4

spreading plate boundaries, force = tension
depth = <10km
weakest magnitude

Question 5

transform boundary

Answer 5

fault boundary where 2 plates slide past each other, force = shear
intermediate depth
intermediate magnitude

Question 6

focus

Answer 6

origin of where fault first slipped, center of seismic waves

Question 7

epicenter

Answer 7

point on map directly above focus, strongest shaking occurs

Question 8

S Wave

Answer 8

secondary wave, 
shear waves or wiggling motion, moving at 90 degree angles
2nd to arrive
3.5km/s velocity
force = shear
change in shape 
travels through solids

Question 9

p waves

Answer 9

primary waves: compressional waves, sudden jolt
velocity = 6 km/s
1st to arrive
motion parallel, force = compression
change in volume and travel through all mediums

Question 10

surface waves

Answer 10

along surface, series of rolling motions
travel only at earth’s crust
most destructive, but slower than P or S waves

Question 11

Body waves

Answer 11

travels through the earth

Question 12

period

Answer 12

cycle between peak to peak

Question 13

wavelength

Answer 13

distance between wave crest

Question 14

amplitude

Answer 14

amount of positive or negative shift in the earth

Question 15

frequency

Answer 15

number of peaks per second

Question 16

seismograph

Answer 16

records shaking of earthquakes on record. time travel graph helps find epicenter
tool

Question 17

seismology

Answer 17

scientific study of earthquakes and propogation of elastic waves through earth

Question 18

seismogram

Answer 18

recorder (paper with the information on it)
know P&S wave time, distance between P & S
magnitude found from time of arrival and height of amplitude
multiple magnitudes find location of earthquake

Question 19

focal mechanism

Answer 19

direction of slip in an earthquake and orientation of the fault

goes from negative (tension) to positive (compression). creates image of movement for EQ

Question 20

beach ball

Answer 20

represents focal mechanism
P waves produce characteristic motion
first motion describe solution

Question 21

fault plane

Answer 21

3 dimensional movement parallel to plate movement

Question 22

auxiliary plane

Answer 22

line drive pass hypocenter/focus perpendiclar to movement of plates

use to determine push (big up) or pull (big down) motion of earthquake
push= compression, pull = tension

Question 23

magnitude

Answer 23

measure of the amplitude and time of arrival from earthquake.
measures energy released

Question 24

intensity

Answer 24

based on observation of individuals during and after earthquake. severity of shaking

Question 25

Richter Scale

Answer 25

standardized system of magnitude measurement, log 10 scale

Question 26

Mercalli Scale

Answer 26

quantify intensity of earthquake. based on how people felt

Question 27

acceleration

Answer 27

designated as proportion of gravity. most <1g

Question 28

liquefaction

Answer 28

soils that ordinarily seem stable become almost liquid during shaking

requires loose soils and saturation

Question 29

ML and Mw

Answer 29

local magnitude

measure of total energy expended

Question 30

shaking

Answer 30

duration depends on size, distance

severity material dependent

Question 31

isoseismal

Answer 31

used to show lines of equal felt seismic intensity

Question 32

tsunami

Answer 32

harbor wave, rise highest when forced onto harbor, generated by EQ

long wavelength in ocean generated by sudden displacement of water column
E = h^2wavelength
V = SQRT(gD) gravity * depth
high wave comes from continuing energy

Question 33

precursor

Answer 33

signs that forecast EQ. tectonic plate movement, micro earthquakes, change in Radon, ground elevation change, zones of fluid pressure, etc.

Question 34

foreshock

Answer 34

minor earthquakes preceding major

Question 35

paleoseismology

Answer 35

study of prehistoric EQ and fault movements

Question 36

prediction

Answer 36

utilizing warning systems to determine when, where, how large EQ will occur

Question 37

forecasting

Answer 37

utilizing warning system to generate general location, frequency, magnitude of EQ. likelihood over given time

Question 38

seismic gap theory

Answer 38

segments of major faults with less EQ than neighboring segments more likely to have EQ over time.

strain accumulates over time and record of past events help determine likely frequency

Question 39

peak ground acceleration

Answer 39

designated as proportion to gravity

Question 40

risk map

Answer 40

estimation based on probability of risk. where and when EQ will shake based on post activity and given time

Question 41

reinforced concrete

Answer 41

breaks in EQ, leaves enclosed steel frame to fail

Question 42

retrofitting

Answer 42

modifying existing buildings to minimize the damage during strong earthquakes

Question 43

base isolation

Answer 43

isolate buildings from shaking grounds
buildings break if weak floors due to lateral movement.
sway related to frequency: resonance more sway,

Question 44

isoseismal map

Answer 44

shows lines of equal felt seismic intensity

Question 45

seismic risk

Answer 45

depicts probability of impact within specified area