China's deadly earthquake in the Sichuan province has again showed that ground-based earthquake prediction methods and systems are not reliable. Traditional seismology does its best, sometimes succeeding, but more often only saying something like, "California will be destroyed in the next 30 years." Remote sensing from space can provide more accurate data about locations, and even dates of expected disasters. The majority of earthquakes happen in two long narrow stripes, one around the Pacific and the other running from the Azores to southeast Asia. There are several other earthquake-prone regions. Half of Russia's Far East is in a seismically hazardous zone, and the seismic stations there, with only minor error, can give the future epicentre, its depth under the surface, and its magnitude. But they cannot say when the earthquake will happen.
Many methods
There are many methods for predicting when an earthquake will strike, the most reliable being a long-term prediction for several years, and possibly months, ahead. Scientists have predicted a 99.7 per cent chance of a 6.7 magnitude earthquake hitting the U.S. West Coast, more specifically California, in approximately 30 years. Mid-term predictions are highly important but not accurate. The situation with short-term predictions is highly complicated, as shown by the magnitude 9.0 earthquake in Haicheng, China. Warnings were issued days before the February 4, 1975 earthquake and people in nearby cities remained outdoors, despite the cold weather. As a result, many lives were saved.
By that time, China was conducting broad seismological surveys, using Soviet experience. Central and provincial seismic monitoring stations collected data about natural anomalies, which accumulated considerable information. This helped predict the location and date of several earthquakes, including in Haicheng.
First reported
Anomalous ionospheric phenomena were first reported in the 1960s, but they were disregarded along with astrologic predictions and UFO sightings. The breakthrough came when the Soviet Union launched its Intercosmos-19 satellite in 1979. It detected an unusual low-frequency noise in a large area centred near the epicentre of an earthquake that occurred a few hours later. This finding was registered as a Soviet discovery and was later confirmed by other spacecraft.
Ionospheric variations
Harbingers of powerful earthquakes appear approximately five days before the main shock and have specific characteristics that distinguish them from the other ionospheric variations. Registering them is a very complicated task that includes constant satellite monitoring of the earthquake-prone region and regular baseline studies, because baseline changes can point to a brewing earthquake. Many countries, including Russia, are studying the connection between earthquakes and the ionosphere, but not as vigorously as scientists would like. Such surveys were made from the Mir space station, but only for a year even though the results were encouraging.
Vulcan system
In 2001, Russian scientists designed the Vulcan system for monitoring and predicting natural disasters and industrial accidents, which was included in the 2001-2005 federal space program and provided for launching low-and high-orbiting microsatellites. In December 2001, the Complex Orbital Magneto-Plasma Autonomous Small Satellite (COMPASS) was launched to monitor the Earth for possible harbingers of earthquakes and collect requisite data. Its equipment was created in Russia, Hungary, Greece, Ukraine and Poland. Unfortunately, the experiment was cut short because of satellite malfunctions. Studies continued in 2002-2003 from the Meteor-3M satellite. Space-based predictions have been correct for 44 of 47 registered earthquakes.To collect more data, Russia launched the COMPASS-2 satellite in 2006. Although its operation was hampered by malfunctions, it nevertheless quite successfully probed the Earth's underground lithosphere, atmosphere, ionosphere, and magnetosphere to learn how each terrestrial region is connected with a variety of events such as earthquakes, volcanoes, tropical cyclones, and tornadoes.
Running out of time
Methods and equipment for the Vulcan system are being tested on the International Space Station within the framework of the Uragan program. The ISS, which is flying in a relatively low orbit, turned out to be ideal for such studies. With the California earthquake only 30 years away, humankind is running out of time for inventing new reliable space-based earthquake forecasting systems. — RIA Novosti
(The writer is an expert at the Russian Academy of Sciences' Institute of Space Research)
The Hindu, 25 May 2008
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