Sunday 23 October 2011

Major earthquake in Van Province, eastern Turkey. 23 October 2011.

Slightly after 1.40 pm on Sunday 23 October 2011 the Turkish province of Van was shaken by an earthquake with a magnitude of 7.2 on the Richter Scale which occurred at a depth of 20 km, 16 km to the northeast of the provincial capital, also called Van. This was followed by a number of aftershocks, some exceeding 5 on the Richter Scale. This appears to have caused a large number of fatalities; at the time of writing the recorded death-toll has passed 70 and is likely to continue to climb.
Map showing the location of the 23 October quake and its aftershocks. Larger squares represent larger shocks, the reddish square is the most recent (at the time of writing). From the United States Geological Survey.

As of 6.00 pm GMT casualties have been reported in the cities of Van and Ercis (closer to the Iranian border), but there are no reports from the surrounding countryside, or across the border in Iran. The Turkish Red Crescent has dispatched emergency relief to the region, but at present rescue attempts seem to comprise largely local people moving rubble by hand.

Local news report, from the scene of the quake.

Turkey is an extremely earthquake-prone country, as the boundary between the Arabian and Eurasian Plates passes through its eastern provinces (red line on the map above), creating tectonic disturbances as the Arabian Plate pushes northward into the Eurasian. This is causing the Anatolian Block (roughly Turkey, the Greek Islands and the Peloponnese) to rotate anti-clockwise, splitting away from the rest of Eurasia in the north, and subduct beneath (northward moving) Africa in the southeast.

Map showing the stresses upon and movement of the Anatolian Block.

This has lead to a history of devastating earthquakes in Turkey (and Greece & Iran), the most notable of which in recent years was 1999 earthquake on the North Anatolian Fault that killed over 17 000 people in and around the city of Izmit.