The Kalaotoa Fault: A Newly Identified Fault that Generated the Mw 7.3 Flores Sea Earthquake

Abstract We reveal the existence of a previously unknown fault that generated Mw 7.3 Flores Sea earthquake, which occurred on 14 December 2021, approximately 100 km to north Island, in one most complex tectonic settings Indonesia. use double-difference method relocate hypocenters mainshock and aftershocks, determine focal mechanisms using waveform inversion, then analyze stress changes estimate type transfer. Our relocated show this earthquake sequence ruptured at least three segments: source mechanism exhibits dextral strike-slip motion (strike N72°W dip 78° NE) west–east-trending we call Kalaotoa fault, whereas rupture other two segments located west east (striking west-northwest southeast, respectively) may have been triggered by earthquake. The Coulomb change imparted these nearby faults is investigated, with focus regions experience increase few associated aftershocks. Of particular interest are increases central back-arc thrust just north–south-striking Selayar northwest our study region, both be increased risk failure as result unusual sequence.