Recent faulting along Gorontalo fault based on seismicity data analysis and lineament mapping

Abstract

We focused our study to characterize the geometry and activity of Gorontalo fault. We analysed reviewed the ISC seismic catalogue and the BMKG relocated earthquake events available for the time period of 1960 to 2021, located along the expected location of this fault. In addition, we analysed continuous record from local seismic observatory available for the same period. Further, we mapped the lineaments using 8.3-m resolution DEMNAS data. Tens on shallow earthquakes occurred in the vicinity of this fault with a range magnitude of M 2 to 3. Our lineament analysis however does not reveal distinctive pattern that may indicate the fault manifestation at the surface. The NW-SE trending lineaments are coincidence with the mapped trace of Gorontalo Fault. The weak surface manifestation of the fault scarp may be related to the tropical climatic condition of the area which may obliterate the faulting topography. However, we observed alignment of the seismicity distribution with the mapped NW-SE lineament, indicating that the lineament is likely representing active fault and these earthquakes are associated with faulting along this fault. Our study provide indication that the Gorontalo Fault is active and further study is necessary to investigate subsurface geometry and mitigate its seismic hazards.

Analyzing Seismicity Pattern of the Gorontalo Region and Its Surroundings in the Form of Hypocenter Relocation Using Double Difference Method

“…This is shown by the Sulawesi Island tectonic system model in Figure 1. Several areas must be watched out for, such as the intersection or intersection of one fault with another, so it is possible as a very potential location that is continuous to cause earthquake disasters (Efendi, Marliyani, & Pramumijoyo, 2021).…”

“…The seismicity value is measured by reviewing the condition of the level of seismic activity between regions, which is also one of the most important parameters to measure a region's seismicity level. (Apandi & Bachri, 1997;S Bachri et al, 1993) Hypocenter relocation is very important in order to get the seismicity condition of an area accurately so that it can be better in analyzing its tectonic order, as has been done by (Efendi et al, 2021;Gusman et al, 2017;Jayadi et al, 2023;Syafriani et al, 2023). The purpose of this study is to analyze the level of seismicity of the Gorontalo region and its surroundings based on data from the relocation of earthquake hypocenters so that it can be used to understand better and provide more accurate information in reconstructing seismic activity and tectonic order conditions that are closely related to regional geological conditions to mitigate geological natural disasters, especially earthquakes and for development planning in the Gorontalo region and its surroundings.…”