https://jurnal.unimed.ac.id/2012/index.php/geo/article/view/40772 https://doi.org/10.24114/jg.v15i1.40772 - (Vol 15, No 1 - 2023) available at http://jurnal.unimed.ac.id/2012/index.php/geo e-issn (2549-7057) & p-issn (2085-8167) Identification of Fault Zone in Bali| 46 Identification of Fault Zone in Bali Using GGMPlus Gravity and Alos-2 Palsar-2 Data I Putu Dedy Pratama 1,2* , Takahiro Osawa 3,4 , Abd. Rahman As-syakur 5,6 1 Indonesian Agency for Meteorological, Climatological, and Geophysical Agency (BMKG), Indonesia 2 Masters Program in Environmental Science, Udayana University, Indonesia 3 Yamaguchi University International Collaboarion Office (YUICO), Udayana University, Indonesia 4 Center for Research and Application of Satellite Remote Sensing (YUCARS) Yamaguchi University, Japan 5 Center for Remote Sensing and Ocean Sciences (CReSOS) Udayana University, Indonesia 6 Center for Environmental Research (PPLH), Udayana University, Indonesia ARTICLE INFO ABSTRACT Article History: Received: December 04, 2022 Revision: February 02, 2023 Accepted: February 06, 2023 The local active fault in Bali has a small magnitude (M<5) but has destructive potential because it is very close to residential areas. Mapping the fault area on Bali is needed to identify the parameters of faults. This study used gravity data from GGMplus, topographic data from DEMNAS, and lineaments using ALOS-2 PALSAR-2 data. Validation and interpretation using the geological map of Bali and seismicity data. We interpret the subsurface using the gravity derivative method to identify the type of fault movement. Identify fault locations using lineament extraction from SAR data processed by directional filters. The composite image red-green-blue (RGB) for HH, HV, and VV polarization was used for automatic lineament extraction and then corrected manually. The results of the gravity method succeeded in identifying 29 of the 30 faults from the geological map of the Bali sheet and a new spot from PALSAR-2. Bali land has 12 thrust faults, 11 strike-slip faults, and six normal faults. The image of PALSAR-2 (L band) has succeeded in making a fault lineament map for the Bali region. The lineament extraction results from PALSAR-2 obtained four new faults (Pesanggaran, Sepang, Tegal Badeng, and Banyuwedang), while four faults were not identified (Tampaksiring Fault, Plaga, Mambal, and Munduk-Rajasa). NE- SW dominates the strike directions, and the dip angles are 45-80 degrees. We propose 30 faults in Bali, including 26 defects from geological maps with changes in length and location shift and four new marks extracted from automatic lineament. Keywords: Remote Sensing Earthquake Derivative Gravity Lineament SAR Corresponding Author E-mail: checkmate.mail1@gmail.com INTRODUCTION Indonesian Archipelago is strongly related to quarternary plate tectonics (Verstappen, 2010). Indonesia is located at the confluence of three of the world's main tectonic plates: the Eurasian, Indo- Australian, and Pacific. Besides that, there is also the Philippine microplate, which is moving southward to the north of Sulawesi. Therefore, it is unsurprising that Indonesia's Archipelago is prone to tectonic earthquakes. As a result of tectonic processes that occur, earthquakes often occur in most parts of Indonesia. One source of the earthquake identified is the active subduction zone in the western to the eastern part of Indonesia. In addition, the remaining energy from the collision process between the plates will result in faults on land or sea in several islands and seas of Indonesia. The potential for earthquakes in Indonesia must be a concern in reducing disaster risk because it can cause fatalities. During 1815-2019, earthquakes were natural disasters that generated the highest death toll in Indonesia, with a percentage reaching 49% (Fitriyani et al., 2021).