Abstract
Creeping along the North Anatolian fault (NAF) at Ismetpasa (Turkey) was discovered some thirty years ago, about a decade after the first observations of the phenomenon along the San Andreas fault in California. However, little is known about its lateral extent and rate. In order to study its three dimensional nature and rupture characteristics, we use Synthetic Aperture Radar Interferometry (InSAR) and elastic dislocation models compared also with field observations. Interferograms with temporal baselines ranging between 1.25 and 5 years show that the creeping section starts at the western termination of the 1943 (M = 7.6) earthquake rupture. It continues about 70-km to the west, overlapping with the eastern part of the 1944 (M = 7.3) earthquake rupture. Offsets along strike indicate a maximum creep rate of 11 ± 3 mm/year near the mid point of the creeping section decreasing gradually towards the edges. Near Ismetpasa, InSAR data yield 8 ± 3 mm/year of creep rate, consistent with recent instrumental (triangulation and creepmeter) measurements. Modeling of the InSAR and GPS data suggests that the fault-creep occurs most probably at a shallow depth (0-7 km). Our analysis combined with previous studies suggests that creeping might have commenced following the 1944 earthquake, and thus may be a long-lasting, but transient slip episode.
Original language | English |
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Pages (from-to) | 225-234 |
Number of pages | 10 |
Journal | Earth and Planetary Science Letters |
Volume | 238 |
Issue number | 1-2 |
DOIs | |
Publication status | Published - 30 Sept 2005 |
Funding
SAR data set was provided by ESA through project AO-2436. Financial support is from the RELIEF European project (contract: EVG1-CT-2002-00069). A.M. Akoglu was supported by the EU-FP6 TR-Access Mobility Project. We would like to thank Roland Bürgmann and an anonymous reviewer for their suggestions and comments that greatly improved the paper. We also thank Mathieu Ferry for his initial review. This is Institut de Physique du Globe de Strasbourg (IPGS) paper 2005.02-UMR 7516.
Funders | Funder number |
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EU-FP6 TR-Access |
Keywords
- Fault creep
- InSAR
- Ismetpasa
- North Anatolian fault