Methodology

Earthquake Catalog

Earthquake event data (location, magnitude, depth, and related parameters) is sourced from the United States Geological Survey (USGS) Earthquake Hazards Program via their FDSN event web service, filtered to significant earthquakes of magnitude 6.0 and above.

Moment Tensor Solutions

Moment tensor solutions, including fault plane orientations (strike, dip, rake) and full moment tensor components, are sourced from the Global Centroid Moment Tensor (Global CMT) project, accessed via USGS's earthquake product feeds.

Seismic Hazard, Vulnerability, and Risk Indices

Earthquake hazard, vulnerability, and risk index values are retrieved directly from BNPB's (Badan Nasional Penanggulangan Bencana / National Disaster Management Authority) InaRISK geographic information system. The hazard index is derived from a Probabilistic Seismic Hazard Analysis (PSHA), corresponding to a peak ground acceleration (PGA) model with a 2% probability of exceedance in 50 years (approximately a 2,475-year return period), referenced to bedrock conditions, based on the Indonesia Earthquake Hazard Map (Ministry of Public Works, 2010). The vulnerability index combines social (40%), economic (25%), physical (25%), and environmental (10%) components. The risk index is BNPB's own published composite value, retrieved as-is rather than recalculated. All three indices use a 0–1 scale, classified as Low (Rendah), Medium (Sedang), or High (Tinggi).

Active Fault Sources

Active fault and seismic source information is drawn from the PuSGeN (Pusat Studi Gempa Nasional / National Center for Earthquake Studies) 2024 seismic source model, which provides fault geometry, estimated maximum magnitude, and mechanism classification for mapped fault sources across Indonesia. Descriptive summaries for individual named faults are being added progressively and may not yet be available for every source in the dataset.

Administrative Boundaries

Village and administrative region information (province, regency/city, sub-district, and village) is retrieved from BNPB's administrative boundary GIS layers.

Design Response Spectrum (SNI 1726:2019)

Design Response Spectrum (SNI 1726:2019). Seismic hazard parameters used to construct the design response spectrum — peak ground acceleration (PGA), short-period spectral acceleration (Ss), 1-second spectral acceleration (S1), and the long-period transition (TL) — are retrieved from the Indonesian Ministry of Public Works' official “Respon Spektra Indonesia 2021” tool, based on the 2017 Peta Sumber dan Bahaya Gempa Indonesia (Indonesia Earthquake Source and Hazard Map). Site class (SA–SE) reflects local soil conditions and must be selected based on geotechnical investigation; it is not derived from location and is not calculated by this tool. Site coefficients (Fa, Fv) and the design spectrum curve are computed following SNI 1726:2019, Indonesia's national seismic design standard (structurally equivalent to ASCE 7-16, Chapter 11).

Design Response Spectrum for Bridges (SNI 2833:2016)

Design Response Spectrum for Bridges (SNI 2833:2016). For roads and bridges, seismic hazard parameters (PGA, Ss, S1) for return periods of 100, 500, ~1034 (referred to as the “1000-year” level per SNI 2833's own convention), 2500, and 10,000 years are derived from a locally-hosted seismic hazard grid computed via OpenQuake, based on Indonesia's national probabilistic seismic hazard model — a different data source than the live government tool used for the building spectrum. Site class (SA–SE) is user-selected. Site coefficients (Fa, Fv) and the design spectrum follow SNI 2833:2016 (adapted from AASHTO LRFD Bridge Design Specifications), which unlike SNI 1726:2019 has no long-period (TL) transition, and anchors its short-period rising branch to a PGA-derived acceleration (As = FPGA × PGA) rather than a fixed fraction of SDS.

Design Response Spectrum for Dams (SNI 8460:2017)

Design Response Spectrum for Dams (SNI 8460:2017). Dam response spectra are derived from the same locally-hosted OpenQuake seismic hazard grid (PuSGeN 2024 Indonesian National Seismic Hazard Model) used for bridges, and are computed with the same spectral formulation and site-coefficient tables (Fa, Fv) specified in SNI 2833:2016. The difference is the set of hazard levels: SNI 8460:2017 evaluates dam seismic performance at return periods of 500, ~1,034 (the “1000-year” level per SNI 2833's convention), 2,500, and 10,000 years. As with SNI 2833:2016, there is no long-period (TL) transition and the short-period rising branch is anchored to As = FPGA × PGA. Site class (SA–SE) is user-selected and must reflect geotechnical investigation.

Limitations

This site is intended to provide general, publicly available hazard and seismicity information to support awareness and preliminary assessment. It is not a substitute for a site-specific geotechnical or seismic hazard study performed by a qualified professional, and should not be used as the sole basis for engineering design or safety-critical decisions.

Any use of or reliance on the contents of this document is solely at the user's own risk and responsibility. The authors, publishers, and affiliated organizations accept no liability whatsoever for any direct, indirect, incidental, consequential, or other losses or damages arising from the use of, or reliance on, this document.