Rupture Sequence of Three Interrelated Earthquakes at Isparta Angle of Southwestern Turkey
Abstract
Three earthquakes with an interesting interaction occurred at the north tip of Isparta Angle of southwestern Turkey, a tectonic complex with triple plate interaction and with intersecting faults. The first was on December 15, 2000 (Mw=6.0, Event I), and the others were both on February 3, 2002 (Mw=6.5, Event II, and Mw=6.0, Event III). Their source rupture characteristics are determined based on observed surface faulting (limited data), aftershock distributions, and inversion of broadband seismic waveforms. For Event I, the rupture started at the NW end and unilaterally propagated in SE direction for 30 km. It lasted about 13 seconds, releasing a total moment of 1.3×1018 Nt-m. Event II had a very complex source process. The rupture started from the hypocenter and extended about 15 km in a NW direction, overlapping part of the fault zone of Event I. This step lasted about 10 seconds, releasing a total moment of 9.2×1017 Nt-m. Then, a westward propagation rupture was triggered with oblique left-lateral normal motion. It lasted more than 15 seconds and had a relative large moment of 3.5×1018 Nt-m, a prominent part of the source. This may explain why source mechanism solutions obtained from long period data gave an EW trending fault. Event III happened two hours later and ruptured on a SW trending fault, lasting 6 ∼7 seconds and releasing a moment of 1.2×1018 Nt-m. The occurrences of these three events demonstrate an example of rupture evolution in a tectonically complex fault system with different striking directions. The complex rupture process of second event may be explained in terms of dynamic fault branching (Kame, et al., JGR, Vol 108, pp 1-19, 2003).
- Publication:
-
AGU Spring Meeting Abstracts
- Pub Date:
- May 2004
- Bibcode:
- 2004AGUSM.S21B..02L
- Keywords:
-
- 7203 Body wave propagation;
- 7209 Earthquake dynamics and mechanics;
- 7215 Earthquake parameters;
- 7230 Seismicity and seismotectonics