Earthquake Prediction Baffles Scientists
By Vittorio Hernandez | September 5, 2011 3:58 PM EST
Earthquake experts from different parts of the world gathered at the Southern California Earthquake Center to study better ways to forecast tremors. Despite the presentation of several theories on how to predict temblors, the seismologists agreed that more study is needed.
Scientists still could not pinpoint exact dates and hours when would a quake rock a place, but they could already make long-term forecasts based on a region's seismic history. One such prediction, based on California's earthquake registers, is that the state is at a 99.7 per cent risk of being shaken by a magnitude 6.7 tremor by 2038.
One of the participants to the earthquake summit, Washington state seismologist John Vidale, said he is skeptical about science unlocking the Earth's secrets behind the tremors, although what happens during a temblor is quite clear that it is caused by tectonic plates' frequent movement.
Two major earthquakes in the 1960s led seismologists to seek more knowledge about earthquakes and came up with several theories including warping in the Earth's crust, release of radon gas along a fault line, weather and animal and insect behavior prior to a tremor.
There have been several observations in different parts of the world linking tremors with weird animal behavior just prior to the shaking. Staff of the National Zoo in Washington, D.C. observed lemurs, a gorilla and an orangutan turned restless and became very noisy prior to the Aug. 23 earthquake that rocked the East Coast.
Besides animal behavior, other fields of science being looked as possible sources of unlocking the secrets of a quake are in physics and atmospheric science.
One such study was made 11 years ago by a team from the U.S. Geological Survey and the Philippine Institute of Volcanology and Seismology. The study focused on sediments displaced by recent faulting as a method of reconstructing the magnitude and recurrence of past earthquakes on surface-rupturing faults.
The joint study reviewed data from several major earthquakes that rocked the Philippine national capital region the past 1,500 years. It concluded that a range of 200 to 400 years would be the average recurrence of a major tremor instead of the current 310 years on the Marikina Valley fault system.
It also concluded that due to the shorter geomorphical expressed trace of the east Marikina Valley fault at 18 km length, the chance of another temblor stronger than a magnitude 88 on the faults of the system is small.
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