Intensity Assessment and Seismotectonic Causes of Historical Earthquakes in Bangladesh and Surrounding Areas
DOI:
https://doi.org/10.64862/Keywords:
Earthquake Catalog, Declustering, Gutenberg-Richter Relationship, b-value, Peak Ground AccelerationAbstract
Bangladesh lies at the junction of the Indian and Eurasian plates with the Burmese sub-plates, one of the most seismically active regions of South Asia, yet existing hazard models are largely outdated. A declustered and completeness-screened earthquake catalog has been compiled for Bangladesh and its surrounding tectonic setting, removing 46.5% of the original catalog as dependent aftershocks and foreshocks and leaving 2,811 independent events. The Gutenberg–Richter recurrence analysis, limited to earthquakes of Mw ≥ 4.5, gave a b-value of 0.97 — within the range typical of ordinary crustal seismicity — and a mean return period of ~437 years for a Mw 8.0 event, close to the ~400-year strain-accumulation cycle estimated from GPS geodesy. Mapping earthquake density reveals three concentrated zones: the Sylhet–northeastern border, the Chittagong Hill Tracts, and a cluster along the Madhupur Fault just north of Dhaka. Each zone is independently supported by Peak Ground Acceleration (PGA) values from a global hazard model, ranging from 0.14g–0.2g near Dhaka to 0.26g–0.29g in the Chittagong Hill Tracts. These results suggest an underrecognized intraplate fault north of the capital shapes seismic hazard as much as the country's two major plate-boundary systems — the Shillong Plateau margin and the Indo-Burman subduction zone.
References
Akhter, S. H. (2010). Earthquakes of Dhaka. In A. Islam (Ed.), Environment of Capital Dhaka: Plants, Wildlife, Gardens, Parks, Air, Water and Earthquake (Dhaka Celebration Series, 6, pp. 401–426). Asiatic Society of Bangladesh.
Ambraseys, N. N. (2004). Three little known early earthquakes in India. Current Science, 86(4), 506–508. http://www.jstor.org/stable/24107899
Bilham, R., & Hough, S. (n.d.). Future Earthquakes on the Indian Subcontinent: Inevitable Hazard, Preventable Risk.
Cornell, C. A. (1968). Engineering seismic risk analysis. Bulletin of the Seismological Society of America, 58(5), 1583–1606. https://doi.org/10.1785/BSSA0580051583
Gardner, J. K., & Knopoff, L. (1974). Is the sequence of earthquakes in Southern California, with aftershocks removed, Poissonian? Bulletin of the Seismological Society of America, 64(5), 1363–1367. https://doi.org/10.1785/BSSA0640051363
Geological Survey of Bangladesh, Alam, M. K., Shahidul Hasan, A. K. M., Khan, M. R., Whitney, J. W., Abdullah, S. K. M., Queen, J. E., & Geological Survey (U.S.). Office of Scientific Publications. (1990). Geological map of Bangladesh [Map]. Geological Survey of Bangladesh.
https://search.worldcat.org/title/24324996
Gutenberg, B., & Richter, C. F. (1944). Frequency of earthquakes in California*. Bulletin of the Seismological Society of America, 34(4), 185–188. https://doi.org/10.1785/BSSA0340040185
Hossain, Md. S., Xiao, W., Khan, Md. S. H., Chowdhury, K. R., & Ao, S. (2020). Geodynamic model and tectono-structural framework of the Bengal Basin and its surroundings. Journal of Maps, 16(2), 445–458. https://doi.org/10.1080/17445647.2020.1770136
Kayal, J. R., Arefiev, S. S., Baruah, S., Hazarika, D., Gogoi, N., Gautam, J. L., Baruah, S., Dorbath, C., & Tatevossian, R. (2012). Large and great earthquakes in the Shillong plateau–Assam valley area of Northeast India Region: Pop-up and transverse tectonics. Tectonophysics, 532–535, 186–192. https://doi.org/10.1016/j.tecto.2012.02.007
Morino, M., Maksud Kamal, A. S. M., Muslim, D., Ekram Ali, R. Md., Kamal, M. A., Zillur Rahman, Md., & Kaneko, F. (2011). Seismic event of the Dauki Fault in 16th century confirmed by trench investigation at Gabrakhari Village, Haluaghat, Mymensingh, Bangladesh. Journal of Asian Earth Sciences, 42(3), 492–498. https://doi.org/10.1016/j.jseaes.2011.05.002
Petersen, M. D., Moschetti, M. P., Powers, P. M., Mueller, C. S., Haller, K. M., Frankel, A. D., Zeng, Y., Rezaeian, S., Harmsen, S. C., Boyd, O. S., Field, E. H., Chen, R., Rukstales, K. S., Luco, N., Wheeler, R. L., Williams, R. A., & Olsen, A. H. (2014). Documentation for the 2014 update of the United States national seismic hazard maps. https://doi.org/10.3133/ofr20141091
Rahman, M., & Siddiqua, S. (2016). Liquefaction Resistance Evaluation of Soils Using Standard Penetration Test Blow Count and Shear Wave Velocity.
Rezwan, M. M. (2025). Seismic Hazard Assessment for Bangladesh: Integration of Statistical Analysis and Machine Learning Following the 2025 Narsingdi Earthquake. https://doi.org/10.5281/zenodo.17685817
Scholz, C. H. (1968). The frequency-magnitude relation of microfracturing in rock and its relation to earthquakes. Bulletin of the Seismological Society of America, 58(1), 399–415. https://doi.org/10.1785/BSSA0580010399
Steckler, M. S., Mondal, D. R., Akhter, S. H., Seeber, L., Feng, L., Gale, J., Hill, E. M., & Howe, M. (2016). Locked and loading megathrust linked to active subduction beneath the Indo-Burman Ranges.
Nature Geoscience, 9(8), 615–618. https://doi.org/10.1038/ngeo2760
Stepp, J. C. (n.d.). Analysis of Completeness of the Earthquake Sample in the Puget Sound Area and Its Effect on Statistical Estimates of Earthquake Hazard.
Weichert, D. H. (1980). Estimation of the earthquake recurrence parameters for unequal observation periods for different magnitudes. Bulletin of the Seismological Society of America, 70(4), 1337–1346. https://doi.org/10.1785/BSSA0700041337
Downloads
Published
Data Availability Statement
The data that support the findings of this study were collected from publicly available online sources and databases
Issue
Section
License
Copyright (c) 2026 Nepal Society of Engineering Geology (NSEG)
This work is licensed under a Creative Commons Attribution 4.0 International License.
