Manifestations of catastrophic Turkish earthquakes February 6, 2023 in Kryvbas

Abstract

We analyzed the impact of powerful Turkish earthquakes that occurred on February 6, 2023, including a magnitude 7.8 Mw earthquake at 01:17:36 (UTC) in Kahramanmarash—Gaziantep, a magnitude 6.7/6.3 Mw earthquake at 01:28:21 (UTC), and a magnitude 7.5 Mw earthquake at 10:24:50 in Ekinoz—Kahramanmarash, on the territory of Ukraine, particularly in the city of Kryvyi Rih.The study involved the examination of algorithms for processing data recorded at seismic stations belonging to the S.I. Subbotin Institute of Geophysics of the National Academy of Sciences of Ukraine and the Main Center for Special Control of t he State Space Agency of Ukraine. The analysis of digital records from these Turkish earthquakes provided ground shaking intensity parameters at the recording points: Odesa and KryvyiRih had intensity levels below 3, Kremenchuk recorded 2, and Poltava and Kyiv registered 1. The resulting isoseismal map illustrates that the attenuation of wave intensity from the Turkish earthquakes depended on the geotectonic structure of the Ukrainian territory through which the seismic vibrations propagated.
 The monitoring of the water level in a deep well recorded changes in geodynamic (hydrodeformation) processes following the powerful Turkish earthquakes on February 6, 2023. We found the level of fault-fracture groundwater in the territory of Kryvbaswas affected bythe earthquakes. The calculation of the propagation velocity in the upper part of the lithosphere of the rock deformation front showed a value of ≈19.0 km/min (0.5 km/min).Concurrently, a decrease in the groundwater level by 2—3 cm was recorded, making it possible to conclude that after the earthquake, short-period stretchings of the earth’s crust occurred, both in the zone of the Kryvyi Rih—Kremenchutsky fault and over the Ukrainian Shield, in in general.
 The calculated amplitude-frequency characteristics for the geological environment on the territory of Kryvyi Rih revealed that the maximum acceleration of seismic vibrations on the free-soil surface increases relative to bedrock by about 4 times in the frequency range from 1.2 Hz to 1.75 Hz.