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Can earthquakes be predicted?

Explore the reliability of earthquake prediction methods through a discussion on past successful predictions, signs in animals, measurement techniques, and the difference between prediction and warning systems.

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Can earthquakes be predicted?

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  1. Can earthquakes be predicted?

  2. HKU Roundtable forum on Sichuan Quake 2008 Brief notes by Elaine Wong

  3. The General fact of the Quake 12 May, 2008

  4. The hazard • Focal depth: 10 m • Duration of ground shaking: > 80 sec. • Magnitude: 7.8 / 8 / 8.3 • Speed of crustal movement: 3.1 km / sec (3x speed of voice) • Death toll: > 69, 000 • No. of quake lakes / landslide dams formed: 34

  5. The hazard Felt over: 1500 km away The affected area: > 1-2 x the size of the HKSAR Hazard prone area: 417 counties, 19 severe zones The epicenter: - where several faults ruptured together in the zone for about 300 m to the N - the most active seismic zone in China

  6. The relief • Lungmanshan 5000 m • Sichuan Basin 500 m • Tibet plate South China plate Indian plate 4 mm / yr

  7. How reliable is earthquake prediction? • The most successful one in China • Haicheng (NE China) Quake in winter, 1975 • An earthquake warning was issued 9 hours before the strike. • The government evacuate million of people away from the epicenter • What are the signs?

  8. Freaky behaviour in animals • Before the Sichuan Quake (2008) in a zoo: ‘鴕鳥成群狂奔、大雁集體絶食、 亞洲象不斷長鳴、長角羚焦躁不安…..’ • Animal prediction centres in China, 1960s • e.g. successful use of pigeons and cats ‘深圳街蟾蜍上街’(25/5/08)

  9. How reliable is earthquake prediction? • mostly post-shake reports • amateurish report • lack of rigorous and reductionistic investigation • lack of statistics on false alarms

  10. Measurement of earthquake prediction • seismic events • seismic velocity ratio • electrical resistivity • groundwater flow • radon emanation rate • crustal movement • electromagnetics

  11. Prediction vs. warning • Prediction ~ scientific methods involved • Warning ~ interpretation of prediction ~ public policies

  12. Think about it ~ • In the case of the U.S., no warning of 1 single event of earthquake prediction is made so far. • Why?

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