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Forecasting Earthquakes Thailand Training Program in Seismology and Tsunami Warnings, May 2006 Forecasting Earthquakes ・ Difference between Predictions and Forecasts ・ Early Efforts in Earthquake Prediction ・ Long-term Forecasting Earthquake Predictions versus Forecasts

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Presentation Transcript
slide1

Forecasting Earthquakes

Thailand Training Program in Seismology and Tsunami Warnings, May 2006

slide2

Forecasting Earthquakes

  • ・ Difference between Predictions and Forecasts
  • ・ Early Efforts in Earthquake Prediction
  • ・ Long-term Forecasting
slide3

Earthquake Predictions versus Forecasts

Predictions have specific times, locations, and magnitudes

for future earthquakes.

Forecasts are more long-term estimates of earthquake

occurrences with probability information.

slide4

Loading Cycle

Interseismic

Preseismic

Coseismic

Postseismic

Forecast

Short-term (minutes to weeks)

Intermediate (months to 10 years )

Long-term (> 10 years)

slide5

What is needed in an earthquake prediction ?

1. Time

2. Location

3. Magnitude

Frequency of Occurrence of Earthquakes

Allen, 1996

slide6

What is needed in an earthquake prediction ?

1. Time

2. Location

3. Magnitude

4. Indication of confidence (window)

5. Prediction must be presented in accessible

form for later evaluation

6. Chance earthquake occurs anyway as a

random event

Allen, 1996

slide7

Optimism in the 1960’s and 1970’s

‘Now, when will earthquake prediction be possible and an efficient

Forewarningservice available ? …if we start the project presented

here we should be able to answer the question with sufficient certainty

within ten years.’

The Japanese Blueprint (Tsuboi et al, 1962)

‘Based on an assessment of worldwide observations and findings over the

past few years, it is the panel’s unanimous opinion that the development

of an effective earthquake prediction capability is an achievable goal.

…with appropriate commitment and level of effort, the routine announcement

of reliable predictions may be possible within ten years…’

Panel of the US National Research Council (Allen et al., 1976)

In actuality: Can only forecast earthquakes and

mitigate hazard

slide8

Successes and Failures

‘Predicted’

・1973 Blue Mountain Lake

・1975 Haicheng, China

・1978 Oaxaca, Mexico

・1978 Izu, Japan

‘Not Predicted’

・1976 Tangshan, China

(M7.7 650,000 est. casualties)

・2004 Parkfield, California

slide11

Scholz et al., 1973

Dilatancy

hardening

slide13

Prediction of the 1975 Haicheng, China

Earthquake (M7.3)

Prediction based on foreshocks

and animal behavior saved many

lives

slide14

Short-Term Crustal Deformation Precursor

(M 8.1 Tonankai Earthquake 1944)

Mogi, 1984

slide15

Short-Term Electromagnetic Precursor

1989 Loma Prieta Earthquake

Fraser-Smith, et al., 1990

slide16

Intermediate-Term:

Seismicity Patterns

1978 Oaxaca, Mexico (Ohtake et al., 1981)

‘Mogi Doughnut’

Dilatancy Hardening

slide17

Intermediate-Term:

Crustal Deformation

1964 Niigata earthquake

Mogi, 1985

slide18

Intermediate-Term:

Water and Chemical

M 7.0 Izu earthquake 1978

Wakita, 1981

slide19

‘Successfully’Predicted

・1973 Blue Mountain Lake

・1975 Haicheng, China

・1978 Oaxaca, Mexico

・1978 Izu, Japan

slide20

Parkfield Earthquake Prediction Experiment

95% probability that

M5.5 to 6 will occur

1985-1993.

  • Based on
  • Recurrence pattern
  • Characteristic waveforms
slide21

Bakun and McEvilly, 1979

  • Repeating Characteristic Earthquakes
  • M5 foreshock 17 minutes before 1934 and 1966 events
slide24

For short-term prediction, there have been more

negative results than positive results:

Not Predicted

・1976 Tangshan, China

(M7.7 650,000 est. casualties)

・2004 Parkfield, California

Other precursors have not been consistently seen

slide25

Why has there been lack of continued success in observing precursors?

      • Animal experiments have failed
      • Original observations were hindsight
      • Instrumentation
      • Geology dependent (including lights and piezoelectric effects)
      • Predictive algorithms have not worked (at least short-term)
      • Earthquakes may be non-characteristic
      • No connection to tides or planetary alignment
      • No psychics have made consistent predictions
slide26

Earthquake Forecasting

Short-term minutes to weeks

Intermediate-term months to 10 years

Long-term > 10 years

slide27

Recurrence times of earthquakes

  • to forecast future earthquakes
    • Using historic data
    • Using geologic data
slide28

Earthquake Cycle

Periodic Time-predictable Slip-predictable

Shimazaki and Nakata, 1980

slide30

PALEOSEISMOLOGY

Trenching faults to find

geological evidence of

past earthquakes

Pallet Creek site on the San Andreas fault

slide31

Earthquake Cycle

Periodic Time-predictable Slip-predictable

Shimazaki and Nakata, 1980

slide32

Probability

Conditional Probability

100 years

slide33

Variability in Repeating Earthquakes

Well defined recurrence interval

(Small variability)

Wide range of recurrence intervals

(Large variability)

slide34

Loma Prieta 1989

Parkfield 2004

Hector Mines

Landers 1992

Probabilistic Earthquake Forecasting for California

slide35

USGS National Hazard Maps

http://geohazards.cr.usgs.gov/eq/

earthquake hazards
Ground Shaking

Surface Faulting

Landslides and Liquefaction

Avalanches and soil (mud flows)

Earthquake Hazards
slide37

What about Thailand?

・ Low Seismicity

・ No Historical Earthquakes

・ Active Faults (?)

・ Probability is low for

future earthquakes

But earthquakes can happen

in low probability regions

and offshore

NEIC Catalog Seismicity (M>4.5) 1964-2005

slide38

Future Outlook

Will we be able to predict

earthquakes in the future ?

Long-term: Probably

Intermediate term: Maybe

Short-term: Maybe

slide39

Don’t forget that the precursor

to a tsunami is the earthquake.

slide42

Parkfield Earthquake

Prediction Experiment

loading or deformation cycle
Four phases

Interseismic

Preseismic

Coseismic

Postseismic

Loading or deformation cycle
slide44

For short-term precursors, there are currently

more ‘negative’ results than ‘positive’results.

Johnston and Linde, 2002

Kanamori et al., 1996

slide45

Earthquake Prediction Researchin the 1970’s

Distance Measurements on the

San Andreas fault

Matsushiro strainmeter

slide47

M 6.8 Nisqually 2001

Ground Shaking

slide48

Surface faulting

Bei-Fung Bridge near Fung-Yan city, 1999 Chi-Chi, Taiwan earthquake