Relokasi Hiposenter Gempa Bumi Di Jawa Timur 2017-2021 Dengan Metode Double Difference

Aji, Tamara Atika Dary Satyargo (2023) Relokasi Hiposenter Gempa Bumi Di Jawa Timur 2017-2021 Dengan Metode Double Difference. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Penentuan hiposenter dengan metode umum seperti metode Geiger Adaptive Damping (GAD) memiliki kualitas yang kurang baik disebabkan oleh struktur kecepatan yang tidak termodelkan. Hiposenter yang akurat dibutuhkan sebagai acuan dalam identifikasi zona patahan maupun pemetaan daerah rawan gempa. Metode Double Difference merupakan metode relokasi hiposenter relatif yang didasarkan pada jarak hiposenter antara 2 gempa. Proses relokasi terdiri dari 2 tahapan yaitu Ph2dt dan HypoDD. HypoDD merelokasi hiposenter gempa bumi dengan prinsip kerja diferensiasi waktu tempuh gelombang yang didapat dari Ph2dt dengan prosedur iterasi, dimana setiap iterasi differensial parsial lokasi dan pembobotan data akan diperbaharui bergantung dengan nilai misfit saat inversi. Seismisitas wilayah Jawa Timur didominasi oleh gempa dangkal yang tersebar pada laut selatan Jawa. Hal ini terjadi karena berdasarkan geologi pulau Jawa terdapat palung subduksi di wilayah selatan pulau Jawa. Terdapat sedikit gempa dalam yang tersebar di bagian utara Jawa yang mencapai kedalaman 647 km. Pada kedalaman ini terjadi pada zona intraplate atau disebut zona Wadati-Benioff dengan kedalaman relatif terus menerus hingga kedalaman 660 km, terdapat celah seismik antara kedalaman 190-500 km (seismic gap). Seismisitas wilayah Jawa Timur dipetakan menggunakan Generic Mapping Tools (GMT). Berdasarkan peta tersebut terlihat perbedaan signifikan letak episenter sebelum dan setelah relokasi, gempa bergeser ke segala arah dengan jarak maksimal 400 m ditunjukan oleh diagram rose dan diagram kompas. Pergeseran hiposenter ditampilkan pada penampang melintang. Gempa membentuk cluster pada jarak 200–300 km yang mengarah pada penunjaman lempeng
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Determination of the hypocenter using general methods such as the Geiger Adaptive Damping (GAD) method has poor quality due to the unmodelled velocity structure. An accurate hypocenter is needed as a reference in identifying fault zones and mapping earthquake-prone areas. The Double Difference method is a relative hypocenter relocation method based on the hypocenter distance between 2 earthquakes. The relocation process consisted of 2 stages, namely Ph2dt and HypoDD. HypoDD relocates the earthquake hypocenter with the working principle of differentiation of wave travel time obtained from Ph2dt with an iteration procedure, where each iteration of the partial differential location and data weighting will be updated depending on the misfit value during inversion. The seismicity of the East Java region is dominated by shallow earthquakes that spread over the southern seas of Java. This happens because based on the geology of the island of Java there is a subduction trough in the southern region of the island of Java. There were a few deep earthquakes which spread over the northern part of Java which reached a depth of 647 km. At this depth occurs in the intraplate zone or called the Wadati-Benioff zone with a relatively continuous depth to a depth of 660 km, there is a seismic gap between 190-500 km depth (seismic gap). The seismicity of the East Java region was mapped using Generic Mapping Tools (GMT). Based on the map, it can be seen that there is a significant difference in the location of the epicenter before and after the relocation, the earthquake shifted in all directions with a maximum distance of 400 m shown by the rose diagram and compass diagram. The hypocenter shift is shown in the cross section. The earthquakes form clusters at a distance of 200–300 km which lead to plate subduction

Item Type:	Thesis (Other)
Uncontrolled Keywords:	HypoDD, relokasi hiposenter, subduksi.
Subjects:	T Technology > TN Mining engineering. Metallurgy > TN269 Prospecting--Geophysical methods
Divisions:	Faculty of Science and Data Analytics (SCIENTICS) > Physics > 45201-(S1) Undergraduate Thesis
Depositing User:	Tamara Atika Dary Satyargo Aji
Date Deposited:	14 Feb 2023 04:21
Last Modified:	14 Feb 2023 04:21
URI:	http://repository.its.ac.id/id/eprint/97187

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