Proceedings of the 12th International INQUA meeting on paleoseismology, active tectonic and archaeoseismology

362 1 2 T H I N T E R N AT I O N A L I N Q U A M E E T I N G O N PA L E O S E I S M O L O G Y , A C T I V E T E C T O N I C S A N D A R C H A E O S E I S M O L O G Y ( PATA ) , O C T O B E R 6 T H - 1 1 T H , 2 0 2 4 , L O S A N D E S , C H I L E PATA Days 2024 K E Y W O R D S multibeam bathymetry, active fault, Flores Thrust, Kalaotoa Fault (1) Applied Geology Research Group, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung, Bandung, Indonesia (2) Hydrography Research Group, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung, Bandung, Indonesia (3) Geological Engineering, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung, Bandung, Indonesia (4) Geodesy and Geomatics Engineering, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung, Bandung, Indonesia (5) Geodynamics and Sedimentology Research Group, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung, Bandung, Indonesia (6) Spatial and Cadastral Systems Research Group, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung, Bandung, Indonesia *Email: pamumpuni@itb.ac.id Astyka Pamumpuni (1) Gabriella Alodia (2) Indika Aleanry Putra (3) Ana Iffah Sabila (4) Alfend Rudyawan (5) Poerbandono (2) Irwan Meilano (6) PRELIMINARY RESULT OF THE KALAOTOA FAULT IDENTIFICATION BASED ON SEISMIC SECTION AND NEWLY ACQUIRED MULTIBEAM BATHYMETRY A B S T R A C T A 7.4 Mw earthquake that occurred in the Flores Sea, Indonesia, on 14 December 2021 was led to the identification of a new fault system, the Kalaotoa fault. The Kalaotoa fault is located in the Selayar-Alor Ridge, in the Banda-arc system. Data for the study were multibeambathymetry data collected aboard the R/VBaruna Jaya III, relocated earthquake data, and seismic reflection data. The results reveal structural features near the main shock epicenter, including anticlines and fault scarps. The result suggests potential interaction between the Kalaotoa Fault and the Florest Thrust, which could have implications for understanding seismic activity and tectonic in the region. In conclusion, the study successfully identifies the Kalaotoa Fault and highlights the value of multibeam bathymetry in mapping underwater structural features. The findings reveal strike-slip structures as integral components of the Kalaotoa Fault and folding associated with the Florest Thrust. I N T R O D U C T I O N On 14 December 2021, a 7.4 Mw (BMKG, 2021) earthquake occurred in the Flores Sea, Indonesia. The earthquake occurred in a strike-slip mechanism, raising questions regarding its source of activity. A strike-slip fault system, now termed the Kalaotoa fault, has been identified by Supendi et al. (2022) by relocating the mainshocks and aftershocks from seismological data months after the main shock event. However, the geometry and morphology of the fault has not been identified. This study attempts to address the issue by collecting field data through multibeam bathymetry mapping.