VI. International Earthquake Symposium, Kocaeli, Kocaeli, Türkiye, 25 - 27 Eylül 2019, ss.894-897
We studied the source and rupture process of the July 20, 2017 Bodrum-Kos Earthquake
(Mw=6.7) to investigate and better understand the source process and coseismic slip distribution.
Strong ground motion data with three component were collected from Kandilli Observatory and
Earthquake Research Institute, Disaster and Emergency Management Authority and Institute of
Geodynamics Strong Motion Network of Greece selecting 13 stations with 35 components. The
mainshock records were inverted to displacement to retrieve source parameters for the
mainshock through searching for the best CMT location on a 3-D grid scheme. The results
indicate that the best CMT point is located at 6 km depth and shows predominantly normal
faulting mechanism with a considerable strike-slip component; where left-lateral strike-slip
motion has been derived on the nodal planes striking NW-SE and dipping NE, while the sense of
motion is right-lateral-strike-slip on the plane extending NE-SW and dipping SW. The near-field
source modeling of the strong motion data suggests that the main moment release is located
around 4 km of the west of the initial break point and the maximum slip is 1 m, if the shear
modulus is assumed to be 30 GPa. The size of the asperity is about 40 km in length and 20 km in
width, and the duration of rupture is about 13 seconds with Mw = 6.7. The derived average stress
drop of #σ=1.8 MPa. The average displacement is calculated as 0.68 m. Slip distribution shows
a large asperity at shallower part of the fault plane at the eastern side of the hypocenter. The
rupture is very smooth and gradually expands near the hypocenter and propagates bilaterally in
the directions east and west (but mostly to the east). The distribution of the slip vectors indicates
that a normal fault mechanism is dominant during the whole rupture propagation. However, a
small right lateral strike-slip component can be seen at the larger moment release area where
located - W of the hypocenter. The moment release and displacements rates in the shallower
parts of the fault plane are larger than the deeper parts of the fault plane. This could increase the
chances of a continuous surface rupture that could be responsible for tsunami generation.