Forecasting Earthquakes ・ Difference between Predictions and Forecasts ・ Earlier Efforts in Earthquake Prediction ・ Long-term Probability Estimates

  • View
    220

  • Download
    0

Embed Size (px)

Text of Forecasting Earthquakes ・ Difference between Predictions and Forecasts ・ Earlier Efforts in...

  • Slide 1
  • Forecasting Earthquakes Difference between Predictions and Forecasts Earlier Efforts in Earthquake Prediction Long-term Probability Estimates
  • Slide 2
  • Earthquake Predictions versus Forecasts Predictions have specific times, locations, and magnitudes for future earthquakes. Forecasts are more long-term estimates of earthquake occurences. Often they include probability information.
  • Slide 3
  • 1. Time window 2. Location window 3. Magnitude window 4. Indication of confidence 5. Chances earthquake occurs anyways as a random event 6. Prediction must be presented in accessible form for later evaluation What is needed in an earthquake prediction ? Allen, 1996
  • Slide 4
  • 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) Optimism in the 1960 s and 1970 s
  • Slide 5
  • Distance Measurements on the San Andreas fault Matsushiro strainmeter Earthquake Prediction Research in the 1970 s
  • Slide 6
  • Dilatancy
  • Slide 7
  • Slide 8
  • Prediction of the 1975 Haicheng, China Earthquake (M7.3) Prediction based on foreshocks and animal behavior saved many lives
  • Slide 9
  • Scholz et al., 1973
  • Slide 10
  • Short-Term Crustal Deformation Precursor Mogi, 1984
  • Slide 11
  • Short-Term Electromagnetic Precursor Fraser-Smith, et al., 1990
  • Slide 12
  • For short-term precursors, there are currently more negative results than positiveresults. Kanamori et al., 1996 Johnston and Linde, 2002
  • Slide 13
  • Predicted 1973 Blue Mountain Lake (M2.5) 1975 Haicheng, China (M7.3) 1978 Oaxaca, Mexico (M7.7) 1978 Izu, Japan (6.7) Not Predicted 1976 Tangshan, China (M7.7 650,000 casualties) 2003 Tokachi-oki, Japan (M7.9) 2004 Parkfield, California (M6.0) Successes and Failures
  • Slide 14
  • Periodic Time-predicatable Slip-predicatable Shimazaki and Nakata, 1980 Earthquake Cycle
  • Slide 15
  • History of Nankai Earthquakes
  • Slide 16
  • Trenching aults to find geological evidence of past earthquakes Pallet Creek site on the San Andreas fault
  • Slide 17
  • 100 years Conditional Probability Probability
  • Slide 18
  • Well defined recurrence interval Wide range of recurrence intervals (Large variability) (Small variability) Variability in Repeating Earthquakes
  • Slide 19
  • Probabilistic Earthquake Forecasting for California
  • Slide 20
  • the Earthquake Research Committee announced on May 24, 2003, there was 10-20 percent chance of occurrence of a M8-class Off-shore Tokachi Earthquake over the next 10 years starting from January 1, 2003, and a 60 percent chance over the next 30 years Tokachi-oki earthquake September 26, 2004 M8.0
  • Slide 21
  • Probabilistic Hazard Maps Attenuation Relations Proabilistic Earthquake Occurence
  • Slide 22
  • Probabilty of exceedence 10% in 50 years Japan National Seismic Hazard Maps
  • Slide 23
  • http://geohazards.cr.usgs.gov/eq/ USGS National Hazard Maps
  • Slide 24
  • For an earthquake on the southern San Andreas it would take about 30 sec for the S wave to reach Los Angeles. (The S wave travels at about 18,000 km/h.) This is enough time to issue an Early Warning.
  • Slide 25
  • JR 500 series bullet train can reach peak speed of 300 km/hr
  • Slide 26
  • Existing Early Warning Systems UrEDAS SAS (Mexico) Taiwan (EWS) REIS (NIED, JMA) Istanbul, Italy, Greece, Romania plus many other design concepts ElarmS, California

Recommended

View more >