Thailand Training Program in Seismology and Tsunami Warnings, May 2006

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Forecasting Earthquakes
Thailand Training Program in Seismology and
Tsunami Warnings, May 2006
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Forecasting Earthquakes
  Difference between Predictions and
Forecasts   Early Efforts in Earthquake
Prediction   Long-term Forecasting  
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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.
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Loading Cycle Interseismic Preseismic Coseismic
Postseismic
Forecast
Short-term (minutes to weeks) Intermediate
(months to 10 years ) Long-term (gt 10
years)
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What is needed in an earthquake prediction ?
1. Time 2. Location 3.
Magnitude
Frequency of Occurrence of Earthquakes
Descriptor Magnitude Average Annually
Great 8 and higher 1
Major 7 - 7.9 17
Strong 6 - 6.9 134
Moderate 5 - 5.9 1319
Light 4 - 4.9 13,000(estimated)
Minor 3 - 3.9 130,000(estimated)
Very Minor 2 - 2.9 1,300,000(estimated)
Allen, 1996
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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
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Optimism in the 1960s and 1970s
Now, when will earthquake prediction be possible
and an efficient Forewarning service 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
panels 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
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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
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Blue Mountain Lake, NY
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Dilatancy
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Scholz et al., 1973
Dilatancy hardening
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Prediction of the 1975 Haicheng, China Earthquake
(M7.3)
Prediction based on foreshocks and animal
behavior saved many lives
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Short-Term Crustal Deformation Precursor (M 8.1
Tonankai Earthquake 1944)
Mogi, 1984
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Short-Term Electromagnetic Precursor 1989 Loma
Prieta Earthquake
Fraser-Smith, et al., 1990
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Intermediate-Term Seismicity Patterns
1978 Oaxaca, Mexico (Ohtake et al., 1981)
Mogi Doughnut
Dilatancy Hardening
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Intermediate-Term Crustal Deformation 1964
Niigata earthquake
Mogi, 1985
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Intermediate-Term Water and Chemical M 7.0 Izu
earthquake 1978
Wakita, 1981
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Successfully Predicted 1973 Blue Mountain
Lake 1975 Haicheng, China
1978 Oaxaca, Mexico 1978 Izu, Japan
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Parkfield Earthquake Prediction Experiment
95 probability that M5.5 to 6 will
occur 1985-1993.

• Based on
• Recurrence pattern
• Characteristic waveforms

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Bakun and McEvilly, 1979

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

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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
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• 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

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Earthquake Forecasting
Short-term minutes to
weeks Intermediate-term months to 10
years Long-term gt 10 years
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• Recurrence times of earthquakes
• to forecast future earthquakes
• Using historic data
• Using geologic data

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Earthquake Cycle
Periodic Time-predictable
Slip-predictable
Shimazaki and Nakata, 1980
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History of Nankai Earthquakes
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PALEOSEISMOLOGY Trenching faults to find
geological evidence of past earthquakes
Pallet Creek site on the San Andreas fault
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Earthquake Cycle
Periodic Time-predictable
Slip-predictable
Shimazaki and Nakata, 1980
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Probability
Conditional Probability
100 years
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Variability in Repeating Earthquakes
Well defined recurrence interval
(Small variability)
Wide range of recurrence intervals (Large
variability)
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Probabilistic Earthquake Forecasting for
California
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USGS National Hazard Maps
http//geohazards.cr.usgs.gov/eq/
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Earthquake Hazards

• Ground Shaking
• Surface Faulting
• Landslides and Liquefaction
• Avalanches and soil (mud flows)

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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 (Mgt4.5) 1964-2005
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Future Outlook
Will we be able to predict earthquakes in the
future ? Long-term Probably
Intermediate term Maybe Short-term
Maybe
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Dont forget that the precursor to a tsunami is
the earthquake.
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Parkfield Earthquake Prediction Experiment
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Loading or deformation cycle

• Four phases
• Interseismic
• Preseismic
• Coseismic
• Postseismic

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For short-term precursors, there are currently
more negative results than positiveresults.
Johnston and Linde, 2002
Kanamori et al., 1996
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Earthquake Prediction Research in the 1970s
Distance Measurements on the San Andreas fault
Matsushiro strainmeter
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Laser Distance Measurements
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M 6.8 Nisqually 2001 Ground Shaking
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Surface faulting
Bei-Fung Bridge near Fung-Yan city, 1999 Chi-Chi,
Taiwan earthquake
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1964 Niigata Earthquake Liquefaction