Site Characterization by Ambient Noise Geophysical and by Geotechnical Investigations at Mirpur, Dhaka, Bangladesh
DOI:
https://doi.org/10.64862/Keywords:
Site characterization, Microtremor, H/V spectral ratio, Climate-change resilient urbanizationAbstract
Seismic site effects are crucial for seismic hazard assessment and earthquake-resilient urban planning as they play a key role in controlling the intensity of ground shaking experienced during earthquakes. Geophysical measurements based on ambient seismic vibrations, particularly the Horizontal to Vertical spectral ratio (H/V) and array-based methods, provide cost-effective and noninvasive techniques to estimate the fundamental resonance frequency and one-dimensional shear-wave velocity (Vs) profiles, which are directly related to sediment thickness and the site effect potential. Geomorphologically, Dhaka city, including the Mirpur area, occupies the southern part of the Madhupur Tract, surrounded by floodplains of the surrounding rivers. Mirpur, located in the north of Dhaka, falls within the Seismic Zone II of Bangladesh (Z = 0.20g) and is considered moderately earthquake-prone (BNBC, 2020). In this research, 17 H/V measurements were carried out using OYO McSEIS-MT NEO three-component sensors and processed using the Geopsy software. These microtremor results were compared with the borehole standard penetration test (SPT) values with lithological descriptions, multichannel analysis of surface wave (MASW) and downhole PS logging from the Dhaka Urban Geo-information Atlas (2023) to characterize the subsurface conditions. Previous studies reported fundamental frequencies between 0.5 and 4 Hz in Mirpur (Helaly and Ansary, 2021), indicating significant local variation. Nevertheless, the analysis of ambient noise measurements revealed fundamental frequencies between 0.5 and 1.2 Hz, suggesting lower fundamental frequencies than previously reported. The results suggest that the generalized zonation may overestimate local resonance conditions, emphasizing the necessity for site-specific microtremor investigations for reliable seismic site characterization.
References
European Commission, SESAME European Research Project. (2004). Guidelines for the implementation of the H/V spectral ratio technique on ambient vibrations measurements, processing and interpretation (H. B. Havenith, Ed.).
Farazi, A. H., Hossain, M. S., Ito, Y., Piña-Flores, J., Kamal, A. M., and Rahman, M. Z. (2023). Shear wave velocity estimation in the Bengal Basin, Bangladesh by HVSR analysis: Implications for engineering bedrock depth. Journal of Applied Geophysics, 211, 104967. https://doi.org/10.1016/j.jappgeo.2023.104967
GERMAN-BANGLADESH COOPERATION PROJECT “GEO-INFORMATION FOR URBAN DEVELOPMENT.” (2023). Atlas on urban geo-information of Dhaka Metropolitan Region, Bangladesh (A. Günther, Coord.). Hannover–Dhaka.
Helaly, A. L., and Ansary, M. A. (2021). Assessment of seismic vulnerability index of RAJUK area in Bangladesh using microtremor observations. Soils and Rocks. https://doi.org/10.28927/SR.2021.057420
Hobiger, M., Bergamo, P., Imperatori, W., Panzera, F., Marrios Lontsi, A., Perron, V., Michel, C., Burjánek, J., and Fäh, D. (2021). Site characterization of Swiss strong‐motion stations: The benefit of advanced processing algorithms. Bulletin of the Seismological Society of America, 111(4), 1713–1739. https://doi.org/10.1785/0120200316
Monsur, M. H. (1994). Holocene stratigraphy and palaeoclimatological interpretation of the deposits of the Madhupur, Barind and Chalanbil areas of the Bengal Basin, Bangladesh. Bangladesh Journal of Science Research, 12, 255–264.
Nakamura, Y. (1989). A method for dynamic characteristics estimation of subsurface using microtremor on the ground surface. Railway Technical Research Institute, Quarterly Reports, 30(1).
Rahman, M. Z., Siddiqua, S., and Kamal, A. M. (2021). Site response analysis for deep and soft sedimentary deposits of Dhaka City, Bangladesh. Natural Hazards, 106(3), 2279–2305. DOI: 10.1007/s11069-021-04543-w
Schmitz, M., Hernández, J. J., Rocabado, V., Domínguez, J., Morales, C., Vallée, M., García, K., Sánchez-Rojas, J., Singer, A., Oropeza, J., and Coronel, G. (2020). The Caracas, Venezuela, seismic microzoning project: Methodology, results, and implementation for seismic risk reduction. Progress in Disaster Science, 5, 100060. https://doi.org/10.1016/j.pdisas.2019.100060
Downloads
Published
Issue
Section
License
Copyright (c) 2025 Nepal Society of Engineering Geology (NSEG)
This work is licensed under a Creative Commons Attribution 4.0 International License.
