Izvestiya, Physics of the Solid EarthIzvestiya, Physics of the Solid EarthФизика земли0002-33373034-6452The Russian Academy of Sciences24948610.31857/S0002333723060078DTDKQTArticlesСтатьиSource Parameters of Strong Turkish Earthquakes on February 6, 2023 (Mw = 7.8 and Mw = 7.7) from Surface Wave DataОчаговые параметры сильных турецких землетрясений 06.02.2023 г. (Mw = 7.8 и Mw = 7.7) по данным поверхностных волн*FilippovaA. I.ФилипповаА. И.aleirk@mail.ruFomochkinaA. S.ФомочкинаА. С.aleirk@mail.ruPushkov Institute of Terrestrial Magnetism, Ionosphere, and Radio Wave Propagation, Russian Academy of SciencesИнститут земного магнетизма, ионосферы и распространения радиоволн им. Н.В. Пушкова РАНInstitute of the Theory of Earthquake Prediction and Mathematical Geophysics, Russian Academy of SciencesИнститут теории прогноза землетрясений и математической геофизики РАНGubkin Russian State University of Oil and Gas (National Research University)РГУ нефти и газа (НИУ) имени И.М. Губкина0111202368910215012024Copyright ©; 2023, Russian Academy of SciencesCopyright ©; 2023, Российская академия наук2023Russian Academy of SciencesРоссийская академия наукhttps://journals.rcsi.science/0002-3337/article/view/249486

Abstract

—Based on the amplitude spectra of surface waves, the source parameters of the strong Turkish earthquakes of February 6, 2023 (Mw = 7.8 and Mw = 7.7) were calculated in two approximations: an instantaneous point source and an elliptical shear dislocation. As a result, rupture planes were identified, data were obtained on the scalar seismic moment, moment magnitude, focal mechanism, and source depth of the considered seismic events, and the integral parameters characterizing the rupture geometry and its development in time were estimated. It is shown that the sources of the earthquakes under study were formed under the influence of the regional stress field and their focal mechanisms were left lateral faults with a strike direction close to the strike of the East Anatolian fault zone for the first event and close to the strike of the Sürgü-Çardak fault system for the second. For the first earthquake, our estimates of the rupture duration and its length (t = 52.5 s, L = 180 km) probably refer not to the entire rupture, but only to its main phase, confined to the northeastern segments of the East Anatolian fault and characterized by maximum displacements and values of the released seismic moment. The values of t = 30 s and L = 180 km that we obtained for the second earthquake fully characterize the entire rupture.

По амплитудным спектрам поверхностных волн проведены расчеты очаговых параметров сильных Турецких землетрясений 06.02.2023 г. (Mw = 7.8 и Mw = 7.7) в двух приближениях: мгновенного точечного источника и сдвиговой дислокации эллиптической формы. В результате были выделены плоскости разрыва, получены данные о скалярном сейсмическом моменте, моментной магнитуде, фокальном механизме и глубине очага рассматриваемых событий, а также оценки интегральных параметров, характеризующих геометрию разрыва и его развитие во времени. Показано, что очаги исследуемых землетрясений сформировались под влиянием регионального поля напряжений, а их фокальные механизмы представляли собой левосторонние сдвиги с направлением простирания, близким к простиранию зоны Восточно-Анатолийского разлома для первого события и близким к простиранию системы разломов Сургу–Чардак для второго. Для первого землетрясения, полученные нами оценки длительности разрыва и его длины (t = 52.5 с, L = 180 км), вероятно, относятся не ко всему разрыву, а только к его основной фазе, приуроченной к северо-восточным сегментам Восточно-Анатолийского разлома и характеризующейся максимальными смещениями и значениями выделившегося сейсмического момента. Полученные нами для второго землетрясения значения t = 30 c и L = 180 км характеризуют полностью весь разрыв.

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