ANALYSIS OF GEOLOGICAL AND EARTHQUAKES DEFORMATION USING INSAR METHOD IN MAJENE REGENCY, WEST SULAWESI
The Geology of Majene regency and its surrounding area is composed of three volcanic complexes with dozens of geological structures. Geological structures can be active at any time due to tectonic processes such as the two large earthquakes that occurred in 1969 and 1984 in the study area with M? 7....
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| Format: | Final Project |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/69423 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | The Geology of Majene regency and its surrounding area is composed of three volcanic complexes with dozens of geological structures. Geological structures can be active at any time due to tectonic processes such as the two large earthquakes that occurred in 1969 and 1984 in the study area with M? 7.0. On January 14 and 15, 2021 an earthquake shaked Majene Regency with M? 5.7 and M? 6.2. The earthquakes caused deformation which inflicted damages and fatalities in the local area. This study intends to analyze the control of geological features with deformations caused by earthquakes. Considering limited access with steep terrain conditions, remote sensing techniques were applied to observe the geological features and the deformations by utilizing SAR (Synthetic Aperture Radar) Sentinel-1 SLC (Single Look Complex) imagery. The Yamaguchi method was applied to Sentinel-1 intensity image which was integrated with DEMNAS imagery for lineament geological structure identification and vulcanostratigraphic unit interpretation based on morphological boundaries. Furthermore, the D-InSAR (Differential Interferometric Synthetic Aperture Radar) method is applied to the SAR image data pairs to produce the deformation in the form of an interferogram. The descending orbit interferogram (16 and 28 January 2021) shows a maximum deformation of up to 8.35 cm in the LOS (Line of Sight) direction around the Taan fault. Then the ascending orbit interferogram (26 January and 7 February 2021) shows deformation of up to 10.43 cm in the LOS direction around the earthquake location. The result of unwrapping from an interferogram ascending revealed negative deformation near the earthquake location indicating subsidence. The descending interferogram shows a positive deformation to the east of the Taan and Tandeallo faults, and to the south of the Ranteoda fault. The positive deformation is interpreted as a result of the movement of the upward component of the fault. In addition, both orbits of interferogram show that deformation tends to occur in the western part which is dominated by sedimentary rocks compared to the eastern part which is dominated by volcaniclastic rocks. The detected deformations are in areas of high coherence such as in areas of low vegetation. The results of interferogram observations show that deformations were correlated by the earthquake location, rock types, and faults.
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