Analisis Kinematik Rupture Gempa Ganda Turki 6 Februari 2023 Dengan Metode MUSIC BPI
Kinematic Analysis of the Turkey Double Earthquake Rupture on February 6, 2023, Using the MUSIC BPI Method
Pada tanggal 6 Februari 2023, Turki diguncang oleh gempa tektonik yang menarik perhatian dunia karena keunikan karakteristiknya sebagai gempa ganda yang terjadi hanya dalam selisih waktu 9 jam. Gempa pertama terjadi pada pukul 01:17:34 UTC dengan kekuatan Mw 7,8 dan diikuti gempa kedua terjadi dengan kekuatan Mw 7,6. Gempa ganda Turki 2023 berdampak hingga mencapai wilayah barat laut Syria. Fenomena ini menimbulkan banyak pertanyaan terkait proses kinematik rupture. Oleh karena itu, penelitian ini bertujuan untuk menentukan parameter kinematik rupture pada kasus gempa ganda Turki 2023 melalui analisis proses rupture gempa dengan bantuan multiple signal classification back-projection imaging (MUSIC BPI). Analisis dilakukan berbasis sinyal koheren gelombang P berfrekuensi tinggi yang diperoleh dari jaringan stasiun seismik Alaska. Fokus utama penelitian ini adalah penentuan parameter kinematik, yaitu rupture extent, rupture duration, rupture speed, dan rupture directivity. Hasil analisis citra proses rupture gempa beresolusi tinggi mendiskripsikan rupture gempa pertama merambat bilateral ke arah timur laut dan selatan-barat daya sepanjang 180 km dari lokasi episenter. Rupture gempa kedua juga merambat bilateral ke arah barat sepanjang Sesar Sürgü, kemudian ke timur dan berubah arah ke timur laut sepanjang 72 km dari episenter. Analisis radiator seismik mengkonfirmasi gerak rupture gempa pertama dengan kecepatan 2,54 km/s hingga 2,70 km/s selama 75 s dan gempa kedua dengan kecepatan 2,07 km/s hingga 2,34 km/s selama 32 s (kecepatan rupture kedua gempa dikategorikan sebagai sub-shear). Semua temuan pada penelitian ini tidak berbeda signifikan dari temuan terdahulu. Rupture gempa pertama bergerak ke arah barat daya wilayah Turki dengan membawa radiasi seismik yang kuat hingga lepas pantai Latakia Syria yang berada di wilayah barat laut Syria.
Kata kunci: MUSIC BPI, gempa ganda Turki 2023, proses Rupture
On February 6, 2023, Turkey was struck by a tectonic earthquake that drew worldwide attention due to its unique characteristic as a double earthquake occurring within a 9-hour time difference. The first earthquake occurred at 01:17:34 UTC with a magnitude of Mw 7.8, followed by the second earthquake with a magnitude of Mw 7.6. The 2023 Turkey double earthquake had impacts extending to the northwest region of Syria. This phenomenon raised numerous questions regarding the kinematic rupture process. Therefore, this study aims to determine the kinematic rupture parameters in the case of the 2023 Turkey double earthquake through the analysis of the earthquake rupture process using the multiple signal classification back-projection imaging (MUSIC BPI) method. The analysis is based on coherent high-frequency P-wave signals obtained from the seismic station network in Alaska. The primary focus of this research is to determine kinematic parameters, namely rupture extent, rupture duration, rupture speed, and rupture directivity. The results of high-resolution earthquake rupture process imaging describe that the rupture of the first earthquake propagated bilaterally towards the northeast and southwest directions, covering a distance of 180 km from the epicenter location. The rupture of the second earthquake also propagated bilaterally towards the west along the Sürgü Fault, then towards the east and changed direction towards the northeast, covering a distance of 72 km from the epicenter. Seismic radiator analysis confirmed the motion of the rupture of the first earthquake with speeds ranging from 2.54 km/s to 2.70 km/s over 75 seconds, and the second earthquake rupture with speeds ranging from 2.07 km/s to 2.34 km/s over 32 seconds (the rupture speed of the second earthquake is categorized as sub-shear). All findings in this study are not significantly different from previous findings. The rupture of the first earthquake moved towards the southwest of the Turkish region, carrying strong seismic radiation offshore to Latakia, Syria, located in the northwest region of Syria.
Keywords: MUSIC BPI, the 2023 Turkey double earthquake, rupture process