Locating and measuring EQs

Question 1

Earthquake waves and propogation

Answer 1

deformation leading to strain and elastic stresses: stick and slip

Question 2

P waves

Answer 2

Primary/comPressional

Question 3

S waves

Answer 3

Secondary/Shear

Question 4

Surface waves [2]

Answer 4

Love or Rayleigh

Question 5

speed of waves

Answer 5

P, S, Surface

Question 6

Shear waves can’t

Answer 6

travel through liquid - shadow beyond 104 degrees

Question 7

Refraction of P waves

Answer 7

shadow 104-140 degrees

Question 8

Seismometers

Answer 8

Detect passage of seismic waves
Masses and springs
Anchored to bedrock

Question 9

Seismograms

Answer 9

Smoked drum or paper roll. Record rotates continuously, pen moves and leaves wiggles

Question 10

Seismic measuring

Answer 10

vertical, N/S, E/W

Amplitude recorded proportional to velocity of the ground motion

Question 11

WWSSN

Answer 11

World Wide Standard Seismic Network in the 1960s

Question 12

Triangulation

Answer 12

epicentral distance to 3 stations + (P and S time differences

Question 13

General magnitude

Answer 13

M= log(A/T) + f(d,h) + Ceq + Crec
A = amplitude, T = period, f = correction for epicentre distance D and focal depth H
Ceq = region correction
Crec = station correction

Question 14

Local magnitude [ML]

Answer 14

Richter scale, invalid for M>8

Question 15

Surface wave magnitude [Ms]

Answer 15

Ms = log10(A/T)max + 1.66log10 delta + 3.3
A = amplitude of ground motion in units 10^6m
T = time in seconds
delta = epicentral distance in degrees

Question 16

Ms correlates with

Answer 16

damage

Question 17

Body wave magnitude [Mb]

Answer 17

For deep focus >50km
Mb = log10 (A/T)max + q (delta, h)
q= correction function based on epicentral range

Question 18

Seismic moment [Mo]

Answer 18

Mo = U A u
A = area of fault plane
U = shear modulus of deformed rocks
U = avergae slip
unbounded

Question 19

Moment Magnitude [Mw]

Answer 19

Mw = (log Mo) / 1.5 - 6.0

Question 20

Magnitude and Energy

Answer 20

log10 E = 5.24 + 1.44 Ms

Question 21

European Macroseismic Intensity Scale

Answer 21

worded descriptions but relies upon accurate reporting, presence of people