FAILURE STRESS CHANGE CAUSED BY THE 1992 ERZINCAN EARTHQUAKE (MS=6.8)

We calculated Coulomb failure stress change caused by the March 13, 19 92 Erzincan, Turkey, earthquake, and explored the relationship between failure stress and the aftershock distribution which includes the Pul umur earthquake (Ms=5.8) that occurred two days later. One of the most significant features of the Erzincan earthquake was the location of a ftershocks, which did not correspond with either the eastern segment o f the North Anatolian fault zone or the Ovacik fault. This feature can be explained by mapping the failure stress due to the Erzincan earthq uake. The map revealed that there is a significant correlation between the aftershock distribution and the areas where static stress was rai sed by greater than or equal to 0.3 bar. The 1992 Erzincan earthquake raised the Coulomb failure stress about 1.4 bar at the site of the Pul umur event. This stress rise and optimum orientation of the Pulumur fa ult favoured its occurrence.