Analisis Propagasi Rupture Gempabumi Halmahera Selatan 14 Juli 2019 Menggunakan Metode Back-Projection dan Validasinya terhadap Model Finite Fault USGS
DOI:
https://doi.org/10.29303/goescienceed.v7i4.3180Keywords:
Back-Projection, MUSIC-BP, Finite Fault, Rupture, Sorong-Bacan Fault.Abstract
The South Halmahera region lies within a complex tectonic zone controlled by the Sorong-Bacan Fault system, making the rupture characteristics of large earthquakes in this area important to examine in detail. This study applies the Multiple Signal Classification Back-projection (MUSIC-BP) method to map the spatiotemporal dynamics of high-frequency P-wave energy release during the Mw 7.2 South Halmahera earthquake of July 14, 2019, using vertical-component recordings from 54 stations of the Australian (AU) seismic network at teleseismic distances of 30°-90°. The imaging results reveal a unilateral rupture propagating dominantly southeastward from the hypocenter, lasting 30-35 seconds with an average rupture velocity of ±2.7 km/s. These results are independently validated against the USGS finite fault model through its three output products: surface projection, cross-section of slip distribution, and moment rate function. All three comparisons show strong agreement in propagation direction, rupture velocity, and the duration and pattern of energy release, confirming that the back-projection method can serve as an independent rupture-imaging tool that complements conventional finite fault inversion models.
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