Publication Date:
2022-11-21
Description:
The ML 5.8 earthquake that hit the island of Crete on 27 September 2021 is analysed
with InSAR (Interferometry from Synthetic Aperture Radar) and GNSS (Global Navigation Satellite
System) data. The purpose of this work is to create a model with sufficient detail for the geophysical
processes that take place in several kilometres below the earth’s surface and improve our ability to
observe active tectonic processes using geodetic and seismic data. InSAR coseismic displacements
maps show negative values along the LOS of ~18 cm for the ascending orbit and ~20 cm for the
descending one. Similarly, the GNSS data of three permanent stations were used in PPK (Post
Processing Kinematic) mode to (i) estimate the coseismic shifts, highlighting the same range of
values as the InSAR, (ii) model the deformation of the ground associated with the main shock, and
(iii) validate InSAR results by combining GNSS and InSAR data. This allowed us to constrain the
geometric characteristics of the seismogenic fault and the slip distribution on it. Our model, which
stands on a joint inversion of the InSAR and GNSS data, highlights a major rupture surface striking
214◦, dipping 50◦ NW and extending at depth from 2.5 km down to 12 km. The kinematics is almost
dip-slip normal (rake −106◦), while a maximum slip of ~1.0 m occurred at a depth of ca. 6 km. The
crucial though indirect role of inherited tectonic structures affecting the seismogenic crustal volume
is also discussed suggesting their influence on the surrounding stress field and their capacity to
dynamically merge distinct fault segments.
Description:
Published
Description:
5783
Description:
2T. Deformazione crostale attiva
Description:
3T. Fisica dei terremoti e Sorgente Sismica
Description:
JCR Journal
Keywords:
SAR
;
GNSS
;
interferometry
;
source modelling
;
27 September 2021 earthquake
;
Crete system faults
;
04.06. Seismology
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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