Figure 1 . a ) Seismotectonics of the study area. Star
shows the mainshock hypocenter location and the related focal mechanism
as reported by IRSC. Faults are shown with solid and dashed lines.
Dotted lines marked N-R and Ka are related to the North-Ray and Kahrizak
scarps, respectively, that are uncertain whether created by faulting or
are old shorelines (after Nazari et al., 2010). Vectors are geodetic
surface deformation rates by Djamour et al., (2010), with respect to a
fixed central Iran block. Triangles are the used station data of the
Broadband national Iranian Network (BIN) for moment tensor inversion
(section 2). Hexagons are historical earthquakes (Ambraseys and Melvile,
1982; Berberian and Yeats, 1999; Nazari et al., 2009). Circles are
instrumental earthquakes by Engdahl et al. (2006). Dashed ellipses show
affected regions by historical earthquakes. Fault names are: Ga:
Garmsar; So: Sorkhe; Ey: Eyvanakey; Fi: Firuzkuh; Pi: Pishva; N-T: North
Tehran; Ba: Baijan; Rk: Robat Karim; NR: North Rey. Tehran area is in
Green. MSH in red solid line. b ) Circles: Seismicity recorded
by the IRSC network from 2006 until just before the M 5.1 mainshock.
Colors represent hypocentral depths. Faults are the same as (a). Focal
mechanisms with label G are from the GCMT catalog. The ones without
labels and those labeled 1, 2, and 3 are from small to moderate
magnitude earthquakes (3.6<M<4.8) that occurred from
2006 to 2012 in the region and obtained by inverting local broadband
seismic data for their moment tensors (Momeni, 2012). Triangles are the
Strong motion stations locations of the Iranian Strong Motion Network
(ISMN) that we used their data for extended rupture inversion (section
3).