Publication Date:
2024-01-23
Description:
On the 9th of January 2020, an Mw 6.4 strike-slip earthquake took place north of the Asian
margin of the Bering Sea. The earthquake occurred within the known reverse-right-lateral
active fault zone, called Khatyrka–Vyvenka, which transverses the Koryak Highland from
SE to NW and is thought to be a surface manifestation of the Asian portion of either the
Bering plate boundary or the northern edge of the Alaskan stream. No other strong earthquake
has ever been recorded in this remote uninhabited area and the few existing seismic stations
provide poor quality earthquake locations.We adopt SAR interferometry (InSAR) technique to
define an improved location of the Koryak 2020 earthquake and constrain the seismic source.
The analysis of the 2020 event revealed a previously unknown active fault of left-lateral
kinematics that is possibly hidden and strikes NWtransversely to the Khatyrka–Vyvenka fault
zone. Although several mechanisms could account for left-lateral kinematics of this fault,
we propose that the structure is part of a more extended NW fault structure, that formed in
pre-neotectonic times and has played a role of a pre-existing rheological discontinuity. This
revived NW structure together with a similar structure located easterly, so far aseismic, make
the plate/stream boundary segmented, step-like in plan view. The step-like boundary geometry
may be the result of internal transform deformation of a rigid plate, but it is better explained
by deflections of the Alaskan stream edge at local crustal asperities, which are pre-Cenozoic
terrains.
Description:
Published
Description:
1412–1421
Description:
OST2 Deformazione e Hazard sismico e da maremoto
Description:
JCR Journal
Keywords:
Plate motion
;
Radar interferometry
;
Seismic cycle
;
Asia
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
