An aseismic slip transient on the North Anatolian Fault
Constellations of Synthetic Aperture Radar (SAR) satellites with short repeat time acquisitions allow exploration of active faults behavior with unprecedented temporal resolution. Along the North Anatolian Fault (NAF) in Turkey, an 80 km long section has been creeping at least since the 1944, M_w 7.3 earthquake near Ismetpasa, with a current Interferometric Synthetic Aperture Radar (InSAR)-derived average creep rate of 8 ± 3 mm/yr (i.e., a third of the NAF long-term slip rate). We use a dense set of SAR images acquired by the COSMO-SkyMed constellation to quantify the spatial distribution and temporal evolution of creep over 1 year. We identify a major burst of aseismic slip spanning 31 days with a maximum slip of 2 cm, between the surface and 4 km depth. This result shows that fault creep along this section of the NAF does not occur at a steady rate as previously thought, highlighting a need to revise our understanding of the underlying fault mechanics.
Additional Information© 2016 American Geophysical Union. Received 12 FEB 2016; Accepted 24 MAR 2016; Accepted article online 28 MAR 2016; Published online 14 APR 2016. We used the original COSMO-SkyMed product (copyright ASI-Agenzia Spaziale Italiana, 2013–2016) and processed the acquisitions using the ARIA and ISCE systems developed at JPL/Caltech. COSMO-SkyMed data products are processed at JPL under license from ASI as part of a collaborative project between CIDOT and JPL/Caltech. We thank the French Labex OSUG@2020 for support of B.R. during a visit to Caltech. M.S. was supported by NSF grant EAR-1447107. We also acknowledge support from the ALEAS program (INSU-CNRS). We are grateful to Michel Bouchon and Hyrullah Karabulut for stimulating discussions. We thank the Editor A. Newman and two anonymous reviewers for the constructive comments.
Supplemental Material - grl54258-supitem-0001-supplementary.pdf