Kinematics of the 30 October 2020 Mw 7.0 Neon Karlovasion (Samos) earthquake in the Eastern Aegean Sea: Implications on source characteristics and dynamic rupture simulations


Taymaz T. , Yolsal Çevikbilen S. , IRMAK T. S. , Vera F., Liu C., Eken T. , ...More

TECTONOPHYSICS, vol.826, 2022 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 826
  • Publication Date: 2022
  • Doi Number: 10.1016/j.tecto.2022.229223
  • Title of Journal : TECTONOPHYSICS
  • Keywords: Body waves, Computational seismology, Dynamics and mechanics of faulting, Earthquake source observations, Numerical modelling, Waveform inversion, HELLENIC-SUBDUCTION ZONE, TELESEISMIC BODY-WAVE, M-W, ACTIVE TECTONICS, WESTERN TURKEY, SOURCE PARAMETERS, JOINT INVERSION, PALEOMAGNETIC EVIDENCE, NUMERICAL SIMULATIONS, INTERNAL DEFORMATION

Abstract

We resolve source mechanism and rupture process for the Neon Karlovasion, Samos Mw 7.0 earthquake that struck Greek-Turkish border regions on 30th October 2020 acquired from kinematic joint inversion of teleseismic body-waves and near-field strong ground-motion waveforms. The optimal kinematic finite-fault slip model indicates a planar E-W striking north-dipping normal faulting mechanism with strike phi = 270 degrees +/- 5 degrees, dip delta = 35 degrees +/- 5 degrees, rake lambda = -94 degrees +/- 5 degrees; centroid depth h = 11 +/- 2 km; duration of the source time function STF = 26 s and seismic moment M-0 = 3.34 x 10(19) Nm equivalent to Mw = 7.0. Our final finite- fault slip models exhibit two main asperities within a depth range from similar to 20 km to the surface. The dynamic rupture model exposes an initial heterogeneous stress distribution with variations up to 25 MPa. The near-field strong motion waveforms constrained the slip model suggesting up-dip and westward propagation of the bilateral rupture pattern with a maximum slip of 3.2 m, illuminated by back-projection (BP) analysis. The high-frequency (HF) back-projected rupture showed a predominantly E-W striking component (similar to 75%) with directivity of 277 degrees that propagates to the surface along a 60 km long and 24 km wide fault plane in 20 s at a slower speed range of 1.0-2.0 km/s. This well constrains the coseismic slip region where the aftershock sequence confirms distributed deformation. Our back-projection analyses elucidates a dominant HF rupture stage (0-13 s) tracked first on the epicentre area and further along the downdip in the region of maximum coseismic slip indicating similar to 15 km of persistent rupture. The latter HF emissions (13-20 s) remark a speed of about 3.0 km/s and a westward extension of the rupture up to 30 km from the preceding rupture segment to shorelines at the northeast of the Ikaria Island.