3: Earthquake Prediction and Forecasting

Question 1

What three aspects of an earthquake are open for prediction?

Answer 1

Magnitude, location, time

Question 2

Name the 8 possible precursors of an earthquake.

Answer 2

Radon gas
Ultra low frequency EM radiation 
Groundwater level changes
Ground uplift/creep
Change in seismic wave velocities
Change in electrical resistivity
Increase in small local EQ (Foreshocks)
Anomalous animal behaviour

Question 3

What is so famous about the Haicheng EQ of 1975?

Answer 3

Successfully predicted so evacuation was ordered before the earthquake

Question 4

What was the outcome after the Haicheng EQ of 1975?

Answer 4

Many homes destroyed but little loss of life

Question 5

What was the name of the earthquake successfully predicted in 1975?

Answer 5

Haicheng, China.

Question 6

Name two failures of earthquake prediction and the outcomes of each.

Answer 6

Kwangtung province, China, 1976: Evacuation ordered, people lived in tents for 2 months. No earthquake.
Tangshan, China, 1976: No precursors, very fatal EQ (>250,000 deaths)

Question 7

____ predicted that there was a ___% chance of a ___Mw earthquake on ___ +/- ___ days in ____, USA.

Answer 7

Iben Browning, 50%, >6Mw on 3rd Dec 1990, +/- 5 days, New Madrid

Question 8

What were the three ingredients which lead to the possible belief of the earthquake predicted in the USA?

Answer 8

(1) Previous minor EQ same region
(2) Vague prediction, claimed predicted Loma Prieta
(3) Local seismologist said the idea was worth looking at

Question 9

What did the predictor of the USA earthquake claim to be the cause of the earthquake?

Answer 9

Gravitational pull from alignment of sun, moon and planets

Question 10

Name two effects of the prediction of the USA earthquake

Answer 10

Sales in post apocalyptic items surged, people left, people camped outside, media invasion

Question 11

What is the best method to date of long term earthquake forecasting?

Answer 11

Probabilistic forecasting

Question 12

What is the best method to date for very short-term awareness?

Answer 12

Early warning systems

Question 13

What is the theory that earthquake forecasting is based upon?

Answer 13

Elastic rebound theory

Question 14

What three key pieces of information is needed to forecast an earthquake?

Answer 14

Presence of faults, historical EQ data, geodetic data of deformation (loading)

Question 15

Why is it useful to forecast earthquakes in the long-term?

Answer 15

Design and risk mitigation – long-term planning

Question 16

Besides rupture probabilities, what else is needed for planning?

Answer 16

Probabilistic maps of ground shaking intensity

Question 17

___ is an example where earthquake forecasting has taken place. There are multiple scenarios that look at probability over the next ___ years. ____ has predicted that in this timeframe, there is a ___% chance that an earthquake of ___Mw or more will occur.

Answer 17

San Andreas Fault, 30 years, USGS, 99%, 6.7

Question 18

Earthquake prediction is based on ___ and appears to be on timescales of ___ to ___

Answer 18

Detecting precursors, hours to months

Question 19

Earthquake forecasting is based on a ____ approach, on time scales of ___ to ___.

Answer 19

Probabilistic approach, years – centuries

Question 20

Early warning systems give warnings ___ in advance, by detecting ____.

Answer 20

Seconds, P-waves