Claim Missing Document
Check
Articles

Found 2 Documents
Search

Identification of the Subsurface Structure of the Great Sumatra Fault Dikit Segment Based on First Horizontal Derivative (FHD), Second Vertical Derivative (SVD), and Forward Modelling Analyses Forward Modelling of 2D Gravity Anomaly Data Rinanda, Shelya Trya
Jurnal Geofisika Vol 22 No 2 (2024): Jurnal Geofisika
Publisher : Himpunan Ahli Geofisika Indonesia (HAGI)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36435/jgf.v22i2.631

Abstract

The Dikit segment has a length of 66.19067 km, located at coordinates 2.291° - 2.748° N and 101.155° - 101.599° E. This segment shows tectonic activity with a slip rate of 9-11 mm/year. One of the effective Geophysical methods to recognise the presence of faults is the gravity method. The purpose of this study is to determine the distribution pattern of heavy force anomalies and to identify subsurface structures in the Dikit segment area by taking GGMPlus heavy force anomaly data. Based on the Bouguer anomaly value, the high anomaly in this area is controlled by the presence of metamorphic rocks around the study area. Meanwhile, the low Bouguer anomaly is due to the presence of a weak zone around the Gunung Masurai area triggered by geothermal activity in the area. The separation of regional and residual anomalies uses a moving average by taking the average value of the cut-off wave number from the results of the spectrum analysis. Based on the analysis of FHD and SVD values, it has been identified that the Dikit segment has a right strike-slip mechanism that extends from northwest to southeast. Forward modelling was carried out using Grav2DC software to map the subsurface structure in the study area.
STUDI KARAKTERISTIK SESAR BAWEAN (WILAYAH LAUT UTARA JAWA) MENGGUNAKAN ANALISIS TURUNAN DENGAN DATA GAYA BERAT Rinanda, Shelya Trya; Fathoni, Muhammad Yusuf; Haryanto, Yosafat Donni
DiJITAC : Digital Journal of Information Technology and Communication DiJITAC, Vol 5 No.2, April 2025
Publisher : Universitas Islam Negeri Sultan Aji Muhammad Idris Samarinda

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21093/dijitac.v5i2.9636

Abstract

Sesar Bawean merupakan salah satu sesar yang perlu diwaspadai karena terletak di utara Pulau Madura yang memiliki populasi hingga jutaan jiwa. Salah satu langkah mitigasi yang bisa dilakukan adalah pemetaan Sesar Bawean untuk dapat mengetahui karakteristik Sesar Bawean. Dalam penelitian ini, dilakukan pemetaan Sesar Bawean menggunakan analisis turunan dengan data gaya berat dari laman TOPEX yang berupa data FAA (Free Air Anomaly). Data tersebut kemudian diolah hingga mendapatkan nilai FHD (First Horizontal Derivative) untuk menentukan garis dugaan sesar dan SVD (Second Vertical Derivative) untuk menentukan mekanisme sesar. Langkah-langkah dalam mendapatkan nilai FHD (First Horizontal Derivative) dan SVD (Second Vertical Derivative) yaitu penentuan densitas rata-rata mengunakan metode Nettleton, pemisahan anomali regional dan residual dengan metode moving average, pengolahan anomali regional dengan analisis turunan hingga didapatkan peta FHD (First Horizontal Derivative) dan SVD (Second Vertical Derivative). Kemudian dilakukan sayatan pada garis dugaan sesar untuk dapat menentukan garis sesar dan mekanisme sesar secara pasti. Hasil yang didapatkan dari sayatan peta FHD (First Horizontal Derivative) dan SVD (Second Vertical Derivative) menunjukkan bahwa Sesar Bawean memiliki mekanisme berupa sesar naik. Namun, dengan mempertimbangkan dari berbagai sumber, dapat disimpulkan bahwa Sesar Bawean memiliki mekanisme berupa sesar oblique dengan pengaruh mekanisme sesar naik.