Magnitude 6.4 EASTERN TURKEY

Turkey is a tectonically active region that experiences frequent destructive earthquakes. At a large scale, the tectonics of the region near the recent earthquake are controlled by the collision of the Arabian Plate and the Eurasian Plate. At a more detailed level, the tectonics become quite complicated. A large piece of continental crust almost the size of Turkey, called the Anatolian block, is being squeezed to the west. The block is bounded to the north by the North Anatolian Fault and to the south-east by the East Anatolian fault. The recent earthquake occurred near the east end of the East Anatolian fault. The faulting in the region is very complicated and extensive. This earthquake may have been the result of rupture on the northeast trending East Anatolian Fault or it may have occurred on the northwest trending Bingol Karakocan fault zone.

This earthquake occurred 70 km southeast of a magnitude 6.1 earthquake that killed one person and injured several in the Pulumar area on January 27, 2003. These earthquakes are a reminder of the many deadly earthquakes that Turkey has suffered in the recent past. The devastating Kocaeli (Izmit) earthquake of 1999 (M = 7.6) broke a section of the North Anatolian Fault 1,500 km to the west of the recent quake and killed 17,000 people, injured 50,0000, and left 500,000 homeless. The recent earthquake (May 1, 2003) occurred within or near the source region of the M = 6.6 earthquake of March 13, 1992, which killed hundreds of people and left thousands homeless in Erzincan. Another even larger earthquake struck Erzincan in 1939. This magnitude 8.0 earthquake killed an estimated 33,000 people. Erzincan is about 120 km (75 miles) to the northwest of the epicenter of today's earthquake.