Aftershock Distribution in the Eastern Part of the Aftershock Region of the 1999 Izmit, Turkey, Earthquake

Abstract

A temporary seismic network installed in the eastern part of the aftershock region of the 1999 Izmit, Turkey, earthquake revealed that aftershock epicenters were in a very linear alignment near the eastern end of the earthquake fault. The linear alignment extended over a length of about 15 km along the segment of the earthquake fault in an ENE-WSW direction. Hypocenters on the segment are confined to a narrow depth range near the bottom of the seismogenic region. It is inferred from these results that the afterslips occurred in the seismogenic region on the segment before the 1999 Duzce earthquake that occurred in the eastern extension of the Izmit earthquake fault nearly 3 months after the Izmit earthquake. It is possible that the afterslips concentrated larger stress on the fault of the 1999 Duzce earthquake and generated the earthquake earlier. Manuscript received 30 August 2000.