Analisis Preseismic Dan Coseismic Ionospheric Disturbances Pada Gempa Alaska 29 Juli 2021 Dan Gempa Maumere 14 Desember 2021 Dengan Metode 3D Tomografi.

Wulansari, Mega (2022) Analisis Preseismic Dan Coseismic Ionospheric Disturbances Pada Gempa Alaska 29 Juli 2021 Dan Gempa Maumere 14 Desember 2021 Dengan Metode 3D Tomografi. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Global Navigation Satellite System (GNSS) pertama kali diluncurkan untuk keperluan navigasi, tetapi seiring dengan perkembangannya GNSS dapat dimanfaatkan untuk kepentingan observasi deformasi kerak bumi hingga studi mengenai lapisan atmosfer. Data gelombang yang tertunda (delay) dari sinyal GNSS ketika melalui ionosfer dapat dimanfaatkan untuk mendapatkan nilai Total Electron Content (TEC). Nilai TEC tesebut dapat digunakan untuk mempelajari gangguan Ionosfer yang disebabkan oleh aktivita seismik di permukaan bumi, salah satunya gempa bumi. Pada dasarnya, gangguan ionosfer akibat gempa dapat diklasifikasikan dalam dua jenis, yaitu pre-seismic dan Coseismic Ionospheric Disturbance. Dalam penelitian ini, data GNSS dimanfaatkan unutk mendapatkan informasi gangguan ionosfer yang terjadi akibat gempa Alaska tanggal 29 Juli 2021 dan gempa Maumere tanggal 14 Desember 2021. Berdasarkan hasil pengolahan data GNSS-TEC didapatkan bahwa CID terdeteksi pada ~15 menit setelah gempa Alaska 2021 dengan nilai amplitudo maksimum sebesar 1,6723 TECU. Sedangkan pada gempa Maumere 2021, CID terdeteksi pada ~15 menit setelah gempa dengan amplitudo maksimum sebesar 1,6255 TECU. Kenaikan prekusor STEC ditemukan pada studi kasus gempa Alaska 2021 yang diamati oleh satelit GPS 4 dan 16 di beberapa stasiun di sekitar epicenter gempa pada saat ~30 menit sebelum gempa. Kecepatan propagasi gelombang yang menyebabkan adanya CID pada gempa Alaska 2021 dan gempa Maumere 2021, masing-masing sebesar 0,814±0,063 hingga 4,383±0,040 km/s dan 0,318 ± 0,037 hingga 0,994 ± 0,051 km/s. Model 3D tomografi dibuat untuk menganalisis gangguan ionosfer secara spasial dan temporal. Model 3D tomografidilakukan pada ketinggian 100 km – 700 km di atas wilayah studi dengan interval Waktu setiap menit. Hasil pemodelan mampu memvisualisasikan adanya gangguan ionosfer sebelum dan setelah gempa Alaska 2021 dan setelah gempa Maumere 2021. Hasil model 3D tomografi menunjukkan anomali positif ditemukan pada ketinggian 300 sampai 500 km. Hal ini sesuai dengan karakteristik variasi lapisan ionosfer, dimana ketinggian 300-500 km termasuk dalam lapisan F. Anomali tersebut dominan pada ketinggian 300 km yang sesuai dengan model Chapman, dimana ketinggian ionosfer yang mengalami ionisasi maksimum terdapat pada ketinggian ~300 km (lapisan F).
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The Global Navigation Satellite System (GNSS) was first launched for navigation purposes, but along with its development, GNSS can be used for the purposes of observing deformation of the earth's crust to studying the layers of the atmosphere. The delayed signal from the GNSS when pass through the ionosphere can be utilized to obtain the Total Electron Content (TEC) value. The TEC value can be used to study the ionospheric disturbances caused by seismic activity on the earth's surface, such as earthquakes. Basically, ionospheric disturbances due to earthquakes can be classified into two types, namely pre-seismic and Coseismic Ionospheric Disturbance (CID). In this study, the GNSS-TEC data is used to obtain information on ionospheric disturbances that following the Alaska earthquake on July 29, 2021 and the Maumere earthquake on December 14, 2021. Based on the results of processing GNSS-TEC, it was found that CID was detected at ~15 minutes after the 2021 Alaska earthquake with a maximum amplitude value of 1,67 TEC. Whereas in the 2021 Maumere earthquake, CID was detected at ~15 minutes after the earthquake with a maximum amplitude of 1,63 TECU. The increase in STEC precursors was found in a case study of the 2021 Alaska earthquake observed by GPS satellites 4 and 16 at several stations around the epicenter at ~30 minutes before the earthquake. Speed of the wave propagation that caused the CID in the 2021 Alaska earthquake and the 2021 Maumere earthquake were 0,814±0,063 to 4,383±0,040 km/s and 0,318 ± 0,037 to 0,994 ± 0,051 km/s, respectively. A 3D tomographic model was modeled to analyze spatial and temporal disturbances of the ionosphere. The 3D tomography model was carried out at an altitude of 100 km – 700 km above the study area in every minute. The modeling results can visualize the presence of ionospheric disturbances before and after the 2021 Alaska earthquake and after the 2021 Maumere earthquake. The 3D tomographic model results show positive anomalies found at an altitude of 300 km to 500 km. This is in accordance with the characteristics of variations in the ionosphere layer, where an altitude of 300km to 500 km is included in the F layer. The anomaly is dominant at an altitude of 300 km which is in accordance with the Chapman model, where the height of the ionosphere that experiences maximum ionization is at an altitude of ~300 km (F layer).

Item Type:	Thesis (Other)
Additional Information:	RSG 551.22 Wul a-1 2022
Uncontrolled Keywords:	Gempa Bumi, Gangguan Ionosfer, GNSS-TEC, 3D Tomografi. Earthquake, Ionospheric Disturbance, GNSS-TEC, 3D Tomography.
Subjects:	Q Science > QE Geology > QE538.5 Seismic tomography; Seismic waves. Elastic waves
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geomatics Engineering > 29202-(S1) Undergraduate Thesis
Depositing User:	Mr. Marsudiyana -
Date Deposited:	18 May 2026 08:37
Last Modified:	18 May 2026 08:37
URI:	http://repository.its.ac.id/id/eprint/133235

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