Aug. 12, 2003 COLUMBIA, Mo. – In Turkey, the phrase “solid as a rock” does not mean much. More than 30 magnitude-7 quakes have rocked the country over the past century. Earthquakes are such a way of life in this second-world country that seismologists are celebrities. A few years ago, an earthquake expert was voted the sexiest man in the country. Eric Sandvol doesn’t care about celebrity; the geophysicist at the University of Missouri-Columbia simply wants to study the earth’s interior in a geographical area that, in geological time, is rapidly changing.
“That gives you an idea of how important seismology is to the Turkish people,” Sandvol says. “The entire country is seismically active. There are very few stable areas. But seismologists have to be very careful because we cannot predict earthquakes. Like a weatherman, we might be able to forecast the likelihood of a major earthquake occurring over the next 30 years, but we don’t know precisely when earthquakes will strike. There are no global precursors.”
Sandvol, geologists from Cornell University and several Turkish researchers recently completed a major project in which they observed and measured the earth’s movement in eastern Turkey, an area that is geologically active because two major continental plates are colliding. In addition to causing so many earthquakes, the intersection of the Eurasian and Arabian plates is pushing the earth’s crust upward, thus creating a “baby” mountain belt. Tectonic plates are colliding throughout the earth’s surface, but Sandvol says the plate boundary in eastern Turkey is the largest young collision on land and one that geologists predict will eventually form a mountain range and plateau as large as the Himalayas in Tibet.
Despite the critical importance of geologic and seismic information in Turkey, the area had been ignored due to civil war and political instability in the region. Now that the country is relatively stable and peaceful, researchers have installed equipment to gather new seismic data. Sandvol’s team set up 29 seismic stations to monitor activity in eastern Turkey. Workers installed monitors two feet under the ground’s surface. By measuring the speed of seismic waves generated by earthquakes, the sensors enabled Sandvol to take a “snapshot” of the earth’s interior. He and his colleagues are the first to create a detailed image of the earth in this region.
The data helped the researchers discover a number of important phenomena in the relationship between the continental plates. They found that the earth’s interior in this area is extremely hot and possibly molten. They also discovered that the Arabian plate, which is pushing north at 2 centimeters per year, is not “under-thrusting” beneath the Eurasian plate as geologists previously thought. The two plates are simply pushing each other upward, as well as shoving a much smaller plate, the Anatolian, to the west.
The researchers have submitted their findings in a series of eight papers to Geophysical Research Letters.
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