Resolution of non-double-couple components in the seismic moment tensor using regional networks-II: application to aftershocks of the 1999 M-w 7.4 Izmit earthquake

0430237 - GFÚ 2015 RIV GB eng J - Journal Article
Stierle, E. - Bohnhoff, M. - Vavryčuk, Václav
Resolution of non-double-couple components in the seismic moment tensor using regional networks-II: application to aftershocks of the 1999 M-w 7.4 Izmit earthquake.
Geophysical Journal International. Roč. 196, č. 3 (2014), s. 1878-1888. ISSN 0956-540X. E-ISSN 1365-246X
R&D Projects: GA ČR(CZ) GAP210/12/1491
Institutional support: RVO:67985530
Keywords : earthquake source observations * seismicity and tectonics * continental tectonics: extensional
Subject RIV: DC - Siesmology, Volcanology, Earth Structure
Impact factor: 2.560, year: 2014

We study potential non-double-couple (non-DC) components in aftershocks of the 1999 Izmit earthquake. The Izmit earthquake ruptured a similar to 140-km-long segment of the North Anatolian Fault Zone in northwestern Turkey and was followed by the M-w = 7.1 Duzce earthquake that extended the rupture further to the east. Focal mechanisms of Izmit aftershocks clearly indicate a segmentation of the rupture into several segments, one of which is the Akyazi Plain, a pull-apart structure, where significant non-DC components might be observed. The analysed earthquake catalogue contains waveforms of more than 4000 accurately located events observed at 35 three-component short-period seismic stations. To ensure high-quality data with good focal coverage, we apply strict quality criteria to the aftershock catalogue reducing the number of events to only 33 aftershocks for which stable moment tensors were calculated using P- and S-wave amplitudes. The moment tensors of the 33 analysed aftershocks display significant differences in the percentage of the non-DC components for the three distinct fault segments: the Izmit-Sapanca, Karadere-Duzce and the Akyazi segments.
Permanent Link: http://hdl.handle.net/11104/0235133