Seismicity Analysis of Earthquake in Bengkulu Using Gutenberg-Richter and Omori laws

Fiska Tobamba; Icha Untari Meidji; Harsano Jayadi

Authors

Fiska Tobamba Universitas Negeri Gorontalo
Icha Untari Meidji Universitas Negeri Gorontalo
Harsano Jayadi Universitas Tadulako

Keywords:

Earthquake, Seismicity, Gutenberg-Richter, Omori Utsu, Bengkulu

Abstract

Bengkulu Province is one of the regions in Indonesia with high seismic aktivity because it lies within the Sumatra tectonic plate zone and is crossed by the Sumatra Fault system. This tectonic setting makes Bengkulu highly vulnerable to Earthquake. This study analyzes the seismic characteristics of Bengkulu Using the Gutenberg-Richter law and examines the aftershock pattern following the major earthquake of june 4, 2000, based on the Omori-Utsu law. The data were obtained from the USGS earthquake catalog, consisting of earthquake records from 2015-2025 and afthershock data for 30 days after the mainshock. The Gutenberg-Richter Analysis evaluates the relationship between log10N and moment magnitude (Mw) to determine the a and b values. Meanwhile, Omori-Utsu Analysis examines the relationship between log10 n(t) and log10 (t+c) to obtain the parameters p and k. The result show that Bengkulu's seismicity is dominated by small to moderate earthquakes with relatively low b-values, indicating high tectonic stress conditions. The aftershock Analysis produced a p-value of 1.4822 with an R² value of 0.7767, showing rapid aftershock decay consistent with the Omori-Utsu law. These findings confirm Bengkulu has a high seismic Hazard level, emphasizing the need for continuous mitigation and preparedness efforts.

Downloads

Download data is not yet available.

References

Ardiansyah, S. (2018). Analysis of the Destructive Earthquake in Lebong Regency, Bengkulu, December 6, 2017. Kepahiang Geophysical Station, Bengkulu.

Diantari, HC, Suryanto, W., Anggraini, A., Irnaka, TM, Susilanto, P. and Ngadmanto, D. (2018). Preliminary magnitude of completeness quantification of improved BMKG catalog (2008-2016) in the Indonesian region. IOP Conference Series: Earth and Environmental Science, Vol. 132, no. 012026.

Farid, M., & Mase, L. Z. (2020). Implementation of seismic hazard mitigation on the basis of ground shear strain indicator for spatial plan of Bengkulu city, Indonesia. International Journal of GEOMATE, 18 (69), 199-207.

Godano, C., Lippiello, E. and de Arcangelis, L. (2014). Variability of the b-value in the Gutenberg-Richter distribution. Geophysical Journal International, Vol. 199, Issue 3, pp. 1765-1771

Hadi, AI, Farid, M., & Fauzi, Y. (2012). Mapping of maximum ground vibration acceleration and seismic vulnerability due to earthquakes to support the spatial and regional planning (RTRW) of Bengkulu City. J. Simetri (Jurnal Ilmu Fisika Indonesia), 1(2(D)), 1217-81- 1217-86

Hakim, MFN (2024). The Influence of Earthquake Vulnerability Zone Variations on the Seismic Behavior of Earthquake-Resistant Building Structures in Yogyakarta. Doctoral Dissertation, Islamic University of Indonesia.

Han, Q., Wang, L., Xu, J., Carpinteri, A. and Lacidogna, G. (2015). A robust method to estimate the b -value of the magnitude-frequency distribution of earthquakes. Chaos, Solitons and Fractals, Vol. 81, pp. 103-110.

Jayadi, H., Meidji, IU, & Hidayat, I. (2025). Earthquake Analysis Using the Probabilistic Seismic Hazard Analysis (PSHA) Method in Palu City.

Kencoro, G., Farid, M., Hadi, AI, Fadli, DI, & Sedayu, A. (2023). Analysis of Earthquake-Prone Zones in South Bengkulu Regency Based on Peak Ground Acceleration Using the Kanai Formula. Jurnal Kumparan Fisika, 6 (2), 75-82.

Marzocchi, W., Sandri, L., Heuret, A. and Funiciello, F. (2016). Where giant earthquakes may come. Journal of Geophysical Research: Solid Earth, Vol. 121, no. 10, pp. 7322-7336

Mase, LZ, Sugianto, N., & Refrizon. (2021). Seismic hazard microzonation of Bengkulu City, Indonesia. Geoenvironmental Disasters, 8 (5), 1-17.

Murtianto, H. (2016). Potential Earthquake Damage Due to the Movement of the Sumatran Fault in West Sumatra and its Surroundings. Gea Geography Journal, 10 (1), 80-86.

Popandopoulos, G. A. and Chatziioannou, E. (2014). Gutenberg-Richter law parameters analysis using the Hellenic unified seismic network data through fast-bee technique. Earth Science, Vol. 3, no. 5, pp. 122-131.

Rodrigo, M. R. (2021). A spatio-temporal analogue of the Omori-Utsu law of aftershock sequences. arXiv preprint arXiv:2111.02955.

T. Utsu, "Aftershock and Earthquake Statistics," Journal of the Faculty of Science Hokaido University, vol. i, no. 43, pp. 1-33, 1969.

Taruna, R. M., & Pratiwi, A. (2021). Konversi Empiris Summary Magnitude, Local Magnitude, Body-Wave Magnitude, Surface Magnitude, dan Moment Magnitude Menggunakan Data Gempabumi 1922-2020 di Nusa Tenggara Barat. Jurnal Sains Teknologi dan Lingkungan, 7(1), 1-12.

Zulyanto, A. (2010). The Effect of Fiscal Decentralization on Economic Growth in Bengkulu Province (Doctoral dissertation, Diponegoro University).