Failure stress change caused by the 1992 Erzincan earthquake (Ms=6.8)

Abstract

We calculated Coulomb failure stress change caused by the March 13, 1992 Erzincan, Turkey, earthquake, and explored the relationship between failure stress and the aftershock distribution which includes the Pulumur earthquake (Ms=5.8) that occurred two days later. One of the most significant features of the Erzincan earthquake was the location of aftershocks, which did not correspond with either the eastern segment of the North Anatolian fault zone or the Ovacik fault. This feature can be explained by mapping the failure stress due to the Erzincan earthquake. The map revealed that there is a significant correlation between the aftershock distribution and the areas where static stress was raised 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 Pulumur event. This stress rise and optimum orientation of the Pulumur fault favoured its occurrence.