Small Scale Precursors to Earthquakes Predicting EQs by magnetic field variations.
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Transcript of Small Scale Precursors to Earthquakes Predicting EQs by magnetic field variations.
Small Scale Precursors to Earthquakes
Predicting EQs by magnetic field variations
ULF/VLF before EQs
• Tony Fraser Smith, a professor from Stanford University ``recorded anomalous ultra-low-frequency (ULF) electromagnetic waves in the ground near Corralitos (a town 5 km from epicentre of the Loma Prieta earthquake 1989).’’
• According to Smith, 3 hours before the EQ, the ULF noise level increased nearly 100-fold.
• Do EQ-generating fault zones really emit Electro-magnetic waves?
Explanations
• Charlotte may have the ability to sense extremely small variations in the Earth’s geomagnetic field which could be changing in the areas of high seismic activity.
• Charlotte could be able to hear the rumbling of plate motions ?
Geosensology
• Very controversial subject• Examines biological sensitivity to Earthquakes
and other phenomena • The study of senses and biological systems as
it relates to geodynamics and geologic events.• Pioneered by Charlotte King, a woman who
began hearing sounds in the ULF/VLF range in 1976
Charlotte King
• Ability to hear under the 10Hz range• June 1979, she awoke to a strange sound• The next day, reports of beached whales along
the West Coast • 36 hours after Charlotte heard the sound, there
were a series of EQs in Big Bear, California.• Did Charlotte hear what the whales heard ? A
geodynamical disturbance that affected the whales’ sonar-navigation ?
• No one knows what causes the signals. • Stanford graduate student Alexandr Draganov has
suggests that ground water carries an electrical current as it pushes through faults and cracks in the earth.
• Panayiotis Varotsos of Athens University believes rock on one side of a fault conducts electricity differently than rock on the other. The friction during sliding would release electrical signals.
• "The question remains if any of these signals are real," said Uyeda. "We don't know yet."
Occurrence in animals
• Well known that animals are more sensitive to disturbances
• Often, animals are reported to ``sense`` disasters before they happen.
• There are many recorded historical accounts of animals fleeing towns or acting strangely before EQs
Example: Heicheng Earthquake 1975• Magnitude 7.3 strikes densely populated town of Heicheng in China. • About 1000 casualties, but potential for many more• Earthquake was ``predicted``… ?
• Prediction was based on geophysical anomalies being detected in the area prior to the quake (foreshocks, noises).
• As well, animal behaviour in the area was said to be unusual: - wolves came into the town in packs- dogs barked unusually- snakes came out of hibernation and froze on the surface in the snowThe town of approx. 1 million residents was mostly evacuated before the 7.3 quake. The damage was extensive.
References
• http://www.exploratorium.edu/theworld/sonar/sonar.html
• Charlotte King http://www.viser.net/~charking/core.shtml
• Earthquake Body Radio http://bldgblog.blogspot.ca/2005/10/earthquake-body-radio.html