Earthquake relocation in the Central Alborz region of Iran using a non-linear probabilistic method
2013 (English)In: Journal of Seismology, ISSN 1383-4649, E-ISSN 1573-157X, Vol. 17, no 2, 615-628 p.Article in journal (Refereed) Published
In this study, we calculate accurate absolutelocations for nearly 3,000 shallow earthquakes(≤20 km depth) that occurred from 1996 to 2010 inthe Central Alborz region of northern Iran using a nonlinearprobabilistic relocation algorithm on a localscale. We aim to produce a consistent dataset with arealistic assessment of location errors using probabilistichypocenter probability density functions. Ourresults indicate significant improvement in hypocenterlocations and far less scattering than in the routineearthquake catalog. According to our results, 816earthquakes have horizontal uncertainties in the 0.5–3.0 km range, and 981 earthquakes are relocated withfocal-depth errors less than 3.0 km, even with a suboptimalnetwork geometry. Earthquake relocated aretightly clustered in the eastern Tehran region and aremainly associated with active faults in the study area(the Mosha and Garmsar faults). Strong historicalearthquakes have occurred along the Mosha andGarmsar faults, and the relocated earthquakes alongthese faults show clear north-dipping structures andalign along east–west lineations, consistent with thepredominant trend of faults within the study region.After event relocation, all seismicity lies in the upper20 km of the crust, and no deep seismicity (>20 kmdepth) has been observed. In many circumstances, theseismicity at depth does not correlate with surfacefaulting, suggesting that the faulting at depth doesnot directly offset overlying sediments.
Place, publisher, year, edition, pages
2013. Vol. 17, no 2, 615-628 p.
Earthquake relocation . Probability density functions . Non-linear probabilistic relocation algorithm . Seismicity
IdentifiersURN: urn:nbn:se:uu:diva-198347DOI: 10.1007/s10950-012-9342-3ISI: 000316744800028OAI: oai:DiVA.org:uu-198347DiVA: diva2:615908