Brussels, 08 April 2002
No-one can tell with any great accuracy exactly when and where the next earthquake will strike this planet, but Russian scientists believe magnetic storms are a good place to start looking.
The earth's surface seems rock solid, but it is in fact a dynamic grid of slowly shifting 'tectonic' plates. Although incredibly slow, this motion causes stress to build up in the crust which, beyond a critical threshold, causes a portion of the crust to give way, shifting suddenly and violently - what we feel as earthquakes. Research into this potentially devastating natural phenomenon has focused on a number of geophysical areas such as the earth's rotation, solar activity and now magnetic hydrodynamic causes.
Scientists at the Russian Academy of Sciences have investigated the connection between magnetic storms and earthquakes in the seismically active Central Asian region, which also takes in northern Afghanistan - the site of recent quakes measuring over 6 on the Richter scale, causing untold damage and thousands of deaths.
The trigger effect
Since 1975, researchers have compared some 14 000 earth tremors in Kazakhstan and Kyrgyzstan with around 350 sudden magnetic storms occurring over the same period in the region - concluding with some confidence the propensity for earthquakes increases after a magnetic storm takes place. The relationship is complicated but it is centred on the way magnetic storms, interacting with high-speed plasma streams, cause noticeable vibrations as they hit the earth's magnetosphere. The electromagnetic energy in the storm is converted into mechanical energy through a series of conversions in the rocks, such as the 'piezoelectric effect', which are believed to trigger earthquakes. The researchers hope to better understand the physical nature of this 'trigger effect' in the course of future fieldwork and laboratory experiments.
More information
Shmidt United Institute for Physics of the Earth
Russian Academy of Sciences
Contact: sobolev@uipe-ras.scgis.ru
Source: Research DG http://europa.eu.int/comm/dgs/research/ index_en.html