Perpustakaan Digital ITB

A 7.3 Mw earthquake occurred in the Flores Sea on December 14th 2021, followed by a 7 cm-high baby tsunami near the Flores Island. According to BMKG (Badan Meteorologi Klimatologi dan Geofisika), the earthquake was caused by a strike-slip mechanism. In the year of occurrence, no strike-slip fault has been detected within the Flores Sea area. This study aims to identify the geometric shape of a newly identified fault, recently termed as the Kalaotoa Fault (Supendi, et al., 2022). This study uses bathymetric data from a MBES (multibeam echosounder) survey to identify the structures and geometric shapes of the fault. The data was collected through the EWIN JAGAPATI (Ekspedisi Widya Nusantara Jelajah Gabungan Perairan Timur Indonesia) facilitated by the National Research and Innovation Agency (BRIN) aboard the R/V Baruna Jaya III. To obtain the geometric shape of Kalaotoa Fault, a geomorphometry analyses tool termed SWE (slope weighted eccentricity) is used. The identification was divided into horizontal and vertical component analyses based on the eccentricity and slope value of the bathymetric data. The results of this study show that this fault ruptured with approximately 96.761 km length with dextral strike-slip movement direction. From the obtained bathymetry data, it also can be known that there is also a relation between the Kalaotoa Fault and Flores Back-arc Thrust located near this study area separated by an oceanic basin.