Analysis of 15 December 2000 and 3 February 2002 Sultandağı - Afyon earthquakes

Abstract

We analyzed two moderate size of earthquakes (Mw=6.0, Mw=6.5) occurred in Sultandağı-Afyon, southwestern Turkey on December 15, 2000 and February 3, 2002. Both earthquakes took place on the Sultandağı fault (SF) having normal mechanism with slightly different orientations and same directivities. Both earthquakes ruptured to the northwest of SF. The distance between the epicenters of two events was less than 16 km. We relocated the large magnitude aftershocks and used the closest broadband station (ISP – Isparta Station) to reveal the differences in the directivity. Coulomb stress changes for December 15, 2000 earthquake were calculated and its effect on February 3, 2002 event was explored. It was observed that the December 15, 2000 event increased Coulomb stress up to 4 bar in the area of February 3, 2002 and favored the 2002 rupture. Following both earthquakes, we observed seismic activity triggered in 40 km far from the first mainshock and 25 km from the second. It is considered that the activity took place as a result of dynamic triggering.