Site response measurements and implications to soil liquefaction potential using microtremor H/V in Greater Metro Manila, Philippines

Abstract

This research explores the use of microtremor horizontal-to-vertical spectral ratio (H/V) in obtaining site response characteristics and investigating its relationship with soil liquefaction potential in Greater Metro Manila. We performed single station microtremor measurements in 61 sites along with in situ geotechnical techniques to verify liquefaction potential. The resulting 238 spectral curves were classified according to dominant features and subsequently grouped with the calculated liquefaction potential index (LPI) of the soil. Based on a robust comparison of obtained primary parameters, it is revealed that the shape of the H/V curve, its predominant period and relative amplitude are fundamentally linked to the spatial variability and the shear strength of soils. Therefore, areas of high seismic demand can also have high liquefaction potential, and vice versa. We then correlated the predominant period with the LPI of the soil and extracted a boundary using simple statistical techniques to classify high and low potential for liquefaction subsequently validating its use as a complementary tool for rapid site-specific liquefaction assessment. Such findings are a novel contribution to liquefaction studies employing rapid techniques since the application of microtremors to liquefaction in the Philippines has not been practiced extensively.

Keywords:

• Site response
• microtremor H/V
• predominant period
• liquefaction
• LPI

Acknowledgements

The authors are most grateful to the staff of the Liquefaction Project namely, A. T. Serrano, M. J. V. Reyes, O. P. C. Halasan, K. S. Sochayseng, A. A. T. Magnaye, M. C. Dela Cruz, A. O. Amandy, and E. J. M. Arnoco, for their invaluable insights and expertise for the holistic improvement of this paper. The authors also thank M. I. T. Abigania, M. P. Dizon, D. J. L. Buhay, and E. D. Mitiam for their assistance throughout the entire project duration. The authors also express their gratitude to the SpecificEQ Project for the introduction of the methodology and the software. The authors are also thankful to the Department of Education (DepEd), particularly to the Educational Facilities Division for the administrative assistance and comments that helped in various stages of the project. Special thanks are given to the school principals and Division Engineers for the hospitality and assistance during the fieldwork campaigns.

Author’s contributions

A. D. conceived this study and handled the overall project supervision, administration, and funding acquisition. L. E. A. and O. L. carried out the data acquisition, processing and analysis, and manuscript preparation. A. D., R. G. and R. S. Jr. provided resource and review of the manuscript.

Data availability statement

The data to support the findings of this study are available from the corresponding author, A. D. upon reasonable request.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was funded by the Department of Science and Technology – Philippine Council for Industry, Energy, and Emerging Technology Research and Development (DOST-PCIEERD).