Figure 4 . a ) Correlation between mainshock rupture
(colored ellipses is the surface projection of rupture) and aftershocks
of the first 45 days (filled circles). Stars are mainshock and largest
aftershock hypocenters relocated in this study (section 3). The
mainshock focal mechanism is obtained in section 2. The M4.1 27/05/2020
aftershock focal mechanism is from IRSC. Inner colors represent their
depths. Faults are plotted with red lines. curved lines on the rupture
model represent rupture direction. The square is the location of Mosha
town. The dashed ellipses show the damaged areas of the Ms 5.2 1930 and
Mb 4.0 1955 earthquakes (after Berberian et al., 1993). Other focal
mechanisms are from microearthquakes on the MSH obtained by Tatar et al.
(2012) from June to October 2006. The solid circle is the observed
thermal area on the MSH (after Eskandari et al., (2018). b ) The
directivity effect of the 7th May Mw5.1 mainshock
observed from the PGA recorded in the triggered BHRC network stations in
the region. Strong motion stations are shown in triangles. The black
dashed rectangle shows the area shown in (c). (c) PGA
distribution of the mainshock in the Tehran area. Solid lines
are the active faults (after Talebian et al., (2016)). Strong motion
stations inside Tehran city are shown in reverse triangles. Inner colors
of triangles represent the maximum spectral frequency (Amax) at the
stations. Dashed lines are probable shore-line scarps (after Nazari et
al., 2010).