Open AccessTectonics of the Central Zagros (Iran) deduced from microearthquake seismicity
Author(s) -
Tatar M.,
Hatzfeld D.,
GhaforyAshtiany M.
Publication year - 2004
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.2003.02145.x
Subject(s) - geology , microearthquake , lineament , seismology , crust , induced seismicity , tectonics , slip (aerodynamics) , geophysics , physics , thermodynamics
SUMMARY Microearthquakes in Central Zagros, recorded for 7 weeks in 1997, lie in a ∼6–8 km zone that is likely located beneath 11 km of sediments. They are not located on an active décollement between the sediments and the crystalline crust, but rather define a pattern of NNW–SSE trending lineaments parallel to the fold axes observed at the surface. The spacing between the seismic lineaments is ∼15–20 km and therefore different from that between the folds (∼10–15 km), which suggests that there is not a simple relationship between the two. Focal mechanisms and precise relative locations are consistent with NW–SE striking reverse faulting connected by NNW–SSE striking right lateral strike‐slip faults. The dip of the reverse faults is not certain but is likely NE for the northernmost faults. The strain pattern deduced from the P ‐axes is remarkably similar to the shortening deduced from GPS‐based geodesy suggesting that microearthquakes are the response of the prefractured brittle crust to strain rather than localized on single active faults.