Application of Small Baseline Subset (SBAS)-INSAR Technique to Study Surface Deformation Due to The Grindulu Fault Activities using Sentinel-1 Data

Timur, Annisa Rahmawati (2023) Application of Small Baseline Subset (SBAS)-INSAR Technique to Study Surface Deformation Due to The Grindulu Fault Activities using Sentinel-1 Data. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Numerous variables contribute to the deformation; for instance, local thrust movements, human-made activities, and seismic activity along the Grindulu Fault. The Meteorological, Climatological, and Geophysical Agency of Indonesia (BMKG) reported seismic activities in Pacitan were delivered following November 7, 2019, earthquake, which could indicate the existence of the Grindulu Fault. The location of Grindulu Fault is in the Pacitan Regency on the Southern Coast of Java which directly faces the South Java Subduction zone. In this research, we identify fault activities through the detection around the Grindulu Fault to reduce the disaster risk in Pacitan Regency. Twenty-three ascending Sentinel-1B images and Small Baseline Subset InSAR technique were used to monitor ground deformation in Pacitan Regency between 2019 and 2021. SBAS-InSAR is one of the approaches for analysis techniques that can provide techniques continuous measurements of the ground deformation; it produces mean LOS velocity throughout the Line of Sight (LOS) around the Grindulu Fault segment. The processing was carried out using the GMTSAR software and compared the result using SBAS generated by open-source LiCSBAS of open-source SAR processing result showed deformation in the form of land subsidence in almost all of the Pacitan, with the mean velocity ranging from –2.1 to -43.1 mm/yr. The cause of deformation is the same thing, the existing Grindulu fault. The SBAS result confirmed with geological and geomorphological conditions such Triangular facets, braided rivers, and depression zone near Grindulu fault. Furthermore, the comparison results with the mean LOS velocity from LiCSBAS show that the area around Grindulu Fault also experiences land subsidence. Even though the RMSE value obtained is 13.7 mm/yr, it is demonstrating that the SBASInSAR velocity generated by GMTSAR processing not enough corresponds to the LiCSBAS.
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Banyak variabel berkontribusi pada deformasi; misalnya, gerakan tektonik lokal, atau bahkan aktivitas manusia maupun seismik di sepanjang Sesar Grindulu. Badan Meteorologi, Klimatologi, dan Geofisika Indonesia (BMKG) melaporkan aktivitas seismik di Pacitan terdeteksi yakni berupa gempabumi pada 7 November 2019, yang dapat menjadi indikasi keberadaan Sesar Grindulu. Letak Sesar Grindulu berada di Kabupaten Pacitan dekat dengan Pesisir Selatan Jawa dan berhadapan langsung dengan zona Subduksi Selatan Jawa. Pada penelitian dilakukan identifikasi aktivitas sesar melalui deformasi yang terjadi di sekitar Sesar Grindulu, sehingga dapat mengurangi risiko bencana di Kabupaten Pacitan. Dua puluh tiga citra ascending Sentinel-1B dan teknik Small Baseline Subset InSAR digunakan untuk memantau deformasi tanah di Kabupaten Pacitan antara tahun 2019 dan 2021. SBAS-InSAR adalah salah satu pendekatan untuk memberikan pengukuran deformasi tanah secara kontinu dalam bentuk rata-rata kecepatan deformasi disepanjang Line of Sight (LOS). Pemrosesan dilakukan dengan menggunakan perangkat lunak GMTSAR yang kemudian dibandingkan dengan menggunakan SBAS yang dihasilkan oleh perangkat lunak open source, LiCSBAS. Hasil pengolahan GMTSAR menunjukkan deformasi berupa penurunan muka tanah di hampir seluruh wilayah Pacitan, dengan kecepatan rata-rata berkisar antara –2,1 hingga -43,1 mm/tahun. Penyebab deformasi adalah hal yang sama, yaitu keberadaan sesar Grindulu. Hasil SBAS terkonfirmasi dengan kondisi geologi dan geomorfologi berupa triangular facets, bentuk aliran sungai, dan zona depresi di dekat sesar Grindulu. Selain itu, hasil perbandingan nilai rata-rata kecepatan LOS LiCSBAS menunjukkan bahwa di sekitar Sesar Grindulu juga mengalami penurunan muka tanah. Meskipun nilai RMSE yang diperoleh adalah 13,7 mm/tahun, hal ini menunjukkan bahwa nilai SBASInSAR yang dihasilkan oleh pengolahan GMTSAR belum cukup sesuai dengan hasil LiCSBAS.

Item Type: Thesis (Other)
Additional Information: RSG 535.470 287 Tim a-1 2023
Uncontrolled Keywords: Grindulu Fault, Ground Deformation, Small Baseline Subset (SBAS)-InSAR, Sentinel-1, Active Fault, Sesar Grindulu, Deformasi, Small Baseline Subset (SBAS)-InSAR, Sentinel-1, Sesar Aktif.
Subjects: G Geography. Anthropology. Recreation > G Geography (General) > G70.5.I4 Remote sensing
Q Science > QE Geology > QE598 Land subsidence
Q Science > QE Geology > QE604 Deformation
Divisions: Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geomatics Engineering > 29202-(S1) Undergraduate Thesis
Depositing User: Annisa Rahmawati Timur
Date Deposited: 02 Aug 2023 01:52
Last Modified: 22 Dec 2023 04:04
URI: http://repository.its.ac.id/id/eprint/101407

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