|
 |
 advertisement
| |
|
|
|
|
|
Sliding Plates Shaped Sea Near Turkey
By Frederic Castel
Special to SPACE.com
posted: 12:10 pm ET
17 March 2000
|
marmara_sidebar_000315 From space, higher than bird's-eye images show that the lozenge-shaped Sea of Marmara, whose eastern shore (south of Istanbul) suffered most from the 1999 earthquakes in Turkey, owes its formation to the slippage of plates of Earth at that site that are constantly in motion. And in the course of the last 5 million years, the entire sea (and seabed) subsided several hundred meters, and therefore gradually became larger and wider. Scientists learned this by examining satellite images of the area taken over several years and matching them with data from the ground. Specialists call this a "pull-apart" process because the Earth's crust is literally pulled apart in the section between two strike-slip faults. (A strike-slip occurs when two plates slide past each other like two palms rubbing together.) The French space agency's Earth-imaging Spot satellites observed this same phenomenon, when a miniature pull-apart happened within tens of seconds during one of the 1999 quakes that rattled the coastal town of Golcük. A whole section of the town suddenly dropped a couple of meters, allowing the sea to flow into the streets, extending to 820 feet (250 meters) in length. This submerged portion just near the coast is visible in Spot photos of the area. One photo, snapped three days after the quake, clearly shows the encroaching sea, with the former coastline visible despite smoke disgorged by a burning refinery in the neighboring town of Izmit.
|
|
|
|
|
