Original scientific paper
https://doi.org/10.17794/rgn.2026.3.10
ENHANCING HYPOCENTER RELOCATION FOR SEISMIC HAZARD EVALUATION IN CENTRAL JAVA AND YOGYAKARTA INDONESIA: FINDINGS FROM THE BMKG EARTHQUAKE CATALOG OF AUGUST-OCTOBER 2024
Wahyu Hidayat
; Geophysical Engineering Department, Faculty on Mineral Technology and Energy, Universitas Pembangunan Nasional “Veteran” Yogyakarta, Jl Pajajaran 104, Condongcatur Depok, Sleman Yogyakarta, 55283, Indonesia.
*
Nanda Agustina
; Geophysical Engineering Department, Faculty on Mineral Technology and Energy, Universitas Pembangunan Nasional “Veteran” Yogyakarta, Jl Pajajaran 104, Condongcatur Depok, Sleman Yogyakarta, 55283, Indonesia.
Ekalia Ardenti
; Agency for Meteorology, Climatology, and Geophysics (BMKG), Jl. Raya Banjarmangu No.KM. 12, Kalilunjar, Central Java, 53454 Indonesia.
Suharsono Suharsono
; Geophysical Engineering Department, Faculty on Mineral Technology and Energy, Universitas Pembangunan Nasional “Veteran” Yogyakarta, Jl Pajajaran 104, Condongcatur Depok, Sleman Yogyakarta, 55283, Indonesia.
Ardian Novianto
; Geophysical Engineering Department, Faculty on Mineral Technology and Energy, Universitas Pembangunan Nasional “Veteran” Yogyakarta, Jl Pajajaran 104, Condongcatur Depok, Sleman Yogyakarta, 55283, Indonesia.
Uli Ulfa
; Geophysical Engineering Department, Faculty on Mineral Technology and Energy, Universitas Pembangunan Nasional “Veteran” Yogyakarta, Jl Pajajaran 104, Condongcatur Depok, Sleman Yogyakarta, 55283, Indonesia.
Maman Rohaman
; Geophysical Engineering Department, Faculty on Mineral Technology and Energy, Universitas Pembangunan Nasional “Veteran” Yogyakarta, Jl Pajajaran 104, Condongcatur Depok, Sleman Yogyakarta, 55283, Indonesia.
Herry Riswandi
; Geological Engineering Department, Faculty on Mineral Technology and Energy, Universitas Pembangunan Nasional “Veteran” Yogyakarta, Jl Pajajaran 104, Condongcatur Depok, Sleman Yogyakarta, 55283, Indonesia.
* Corresponding author.
Abstract
We present a hypocenter relocation analysis to examine the distribution of seismicity in the Central Java and Yogyakarta regions in Indonesia. The data were obtained from the BMKG earthquake database for the period August–October 2024, covering the area between 6.0˚–11.0˚ S and 108.5˚–111.6˚ E. The dataset was divided into three monthly groups to observe the spatial and temporal patterns of earthquake sources in the study area. The analysis was carried out by overlaying the relocated hypocenters onto active fault maps and the subduction pattern of southern Java, allowing for a clearer characterization of the earthquake sources. Data from August - October 2024, comprising 393, 424, and 276 earthquake events respectively, were analyzed using the Double - Difference relocation method based on 26,610 - 19,429 P-wave pairs and 21,447 - 15,933 S-wave pairs recorded by 28 seismic stations. The findings reveal significant activity along the Baribis - Kendeng Fault, Kebumen - Meratus Trend, and Progo - Muria Lineament, exhibiting diverse fault mechanisms and hypocenter depths from shallow to intermediate. Clustering near the Opak Fault Zone and associated structures indicates complex fault interactions with potential intersegment stress transfer, while offshore seismicity shows a steeply dipping subduction slab with intermediate- to deep-focus events (50-250 km). The combined occurrence of shallow crustal, intermediate, and deep intraslab earthquakes expands the regional hazard spectrum, highlighting risks of strong ground shaking, site amplification, and localized tsunamis. The findings highlight the importance of integrating multisource and multimechanism earthquake characteristics into probabilistic hazard models to improve spatial planning, infrastructure resilience, and community preparedness.
Keywords
Seismic hazard; Hypocenter relocation; Double – difference; Active fault
Hrčak ID:
347418
URI
Publication date:
26.5.2026.
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