Forecasting Earthquakes Thailand Training Program in Seismology and

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 Predictions have specific times, locations, and magnitudes for future earthquakes. Forecasts are more long-term estimates of earthquake occurrences with probability information.

Loading Cycle Forecast Short-term (minutes to weeks) Interseismic Intermediate (months to 10 years ) Preseismic Long-term Coseismic (> 10 years) Postseismic

What is needed in an earthquake prediction ? 1. Time 2. Location 3. Magnitude Frequency of Occurrence of Earthquakes Average Magnitude Descriptor 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

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

Optimism in the 1960’s and 1970’s ‘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 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

Successes and Failures ‘Predicted’ ・ 1973 Blue Mountain Lake ・ 1975 Haicheng, China ・ 1978 Oaxaca, Mexico ・ 1978 Izu, Japan ‘Not Predicted’ ・ 1976 Tangshan, China (M 7. 7 650, 000 est. casualties) ・ 2004 Parkfield, California

Blue Mountain Lake, NY

‘Dilatancy’

Dilatancy hardening Scholz et al. , 1973

Prediction of the 1975 Haicheng, China Earthquake (M 7. 3) Prediction based on foreshocks and animal behavior saved many lives

Short-Term Crustal Deformation Precursor (M 8. 1 Tonankai Earthquake 1944) Mogi, 1984

Short-Term Electromagnetic Precursor 1989 Loma Prieta Earthquake Fraser-Smith, et al. , 1990

Intermediate-Term: Seismicity Patterns 1978 Oaxaca, Mexico (Ohtake et al. , 1981) ‘Mogi Doughnut’ Dilatancy Hardening

Intermediate-Term: Crustal Deformation 1964 Niigata earthquake Mogi, 1985

Intermediate-Term: Water and Chemical M 7. 0 Izu earthquake 1978 Wakita, 1981

‘Successfully’ Predicted ・ 1973 Blue Mountain Lake ・ 1975 Haicheng, China ・ 1978 Oaxaca, Mexico ・ 1978 Izu, Japan

Parkfield Earthquake Prediction Experiment 95% probability that M 5. 5 to 6 will occur 1985 -1993. Based on • Recurrence pattern • Characteristic waveforms

Bakun and Mc. Evilly, 1979 - Repeating Characteristic Earthquakes - M 5 foreshock 17 minutes before 1934 and 1966 events

For short-term prediction, there have been more negative results than positive results: Not Predicted ・ 1976 Tangshan, China (M 7. 7 650, 000 est. casualties) ・ 2004 Parkfield, California Other precursors have not been consistently seen

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

Earthquake Forecasting Short-term minutes to weeks Intermediate-term months to 10 years Long-term > 10 years

Recurrence times of earthquakes to forecast future earthquakes • Using historic data • Using geologic data

Earthquake Cycle Periodic Time-predictable Slip-predic Shimazaki and Nakata, 1980

History of Nankai Earthquakes

PALEOSEISMOLOGY Trenching faults to find geological evidence of past earthquakes Pallet Creek site on the San Andreas fault

Earthquake Cycle Periodic Time-predictable Slip-predictable Shimazaki and Nakata, 1980

Probability Conditional Probability 100 years

Variability in Repeating Earthquakes Well defined recurrence interval (Small variability) Wide range of recurrence intervals (Large variability)

Probabilistic Earthquake Forecasting for California Loma Prieta 1989 Parkfield 2004 Hector Mines Landers 1992

USGS National Hazard Maps http: //geohazards. cr. usgs. gov/eq/

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

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

Future Outlook Will we be able to predict earthquakes in the future ? Long-term: Probably Intermediate term: Maybe Short-term: Maybe

Don’t forget that the precursor to a tsunami is the earthquake.

Parkfield Earthquake Prediction Experiment

Loading or deformation cycle – Four phases • Interseismic • Preseismic • Coseismic • Postseismic

For short-term precursors, there are currently more ‘negative’ results than ‘positive’results. Johnston and Linde, 2002 Kanamori et al. , 1996

Earthquake Prediction Research　in the 1970’s Distance Measurements on the San Andreas fault Matsushiro strainmeter

Laser Distance Measurements

M 6. 8 Nisqually 2001 Ground Shaking

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

1964 Niigata Earthquake Liquefaction