1887
Volume 42, Issue 1
  • ISSN: 0812-3985
  • E-ISSN: 1834-7533

Abstract

In this study, empirical site amplifications and S-wave velocity profiles for shallow and deep soils are estimated using earthquake ground motion records in metropolitan Manila, the Philippines. We first apply a spectral inversion technique to the earthquake records to estimate effects of source, path, and local site amplification. The earthquake data used were obtained during 36 moderate earthquakes at 10 strong-motion stations of an earthquake observation network in Manila. The estimated value of the propagation path is modelled as 54.61.1. Most of the source spectra can be approximated with the omega-square model. The site amplifications show characteristic features according to surface geological conditions. The amplifications at the sites in the coastal lowland and Marikina Valley shows predominant peaks at frequencies from 1 to 5 Hz, while those in the central plateau are characterised by no dominant peaks. These site amplifications are inverted to subsurface S-wave velocity. We, next, discuss the relationship between the amplifications and average S-wave velocity in the top 30 m of the S-wave velocity profiles. The amplifications at low frequencies are well correlated with the averaged S-wave velocity. However, high-frequency amplifications cannot be sufficiently explained by the averaged S-wave velocity in the top 30 m. They are correlated more with the average of S-wave velocity over depths less than 30 m.

Loading

Article metrics loading...

/content/journals/10.1071/EG11003
2011-03-01
2026-01-25
Loading full text...

Full text loading...

References

  1. Besana G. M. Negishi H. Ando M. 1997 The three-dimensional attenuation structures beneath the Philippine archipelago based on seismic intensity data inversion: Earth and Planetary Science Letters 151 1 11 10.1016/S0012‑821X(97)00112‑X
    https://doi.org/10.1016/S0012-821X(97)00112-X [Google Scholar]
  2. Brune J. 1970 Tectonic stress and the spectra of seismic share waves from earthquakes: Journal of Geophysical Research 75 4997 5009 10.1029/JB075i026p04997
    https://doi.org/10.1029/JB075i026p04997 [Google Scholar]
  3. Daligdig, J.A., and Besana, G.M., 1993, Seismological hazards in Metro Manila: Natural Disaster Prevention and Mitigation in Metropolitan Manila area: Department of Science and Technology, Philippine Institute of Volcanology and Seismology, 9–41.
  4. Daligdig, J.A., Punongbayan, R. S., Besana, G.M., and Tungol, N. M., 1997, The Marikina Valley fault system: Active faulting in eastern Metro Manila: PHIVOLCS professional paper, 1, 1–20.
  5. Gervasio F. C. 1968 The geology, structures, and landscape development of Manila and suburbs: The Philippine Geologist 22 178 192
    [Google Scholar]
  6. Iwata T. Irikura K. 1986 Separation of source, propagation and site effects from observed S-waves: Zisin (Journal of the Seismological Society of Japan) 39 579 593 [in Japanese with English Abstract]
    [Google Scholar]
  7. Joyner, W. B., and Fumal, T. E., 1984, Use of measured shear wave velocity for predicting geologic and site effects on strong ground motion: Proceedings of the 8th World Conference on Earthquake Engineering, 2, 777–783.
  8. Kato K. Takemura M. Ikeura T. Urao K. Uetake T. 1992 Preliminary analysis for evaluation of local site effect from strong motion spectra by an inversion method: Journal of Physics of the Earth 40 175 191
    [Google Scholar]
  9. Kurita, K., Yamanaka, H., Ohmachi, T., Seo, K., Kinugasa, Y., Midorikawa, S., Toshinawa, T., Fujimoto, K., and Abeki, N., 2000, Strong motion observation in Metro Manila, Philippines: The 12th World Conference on Earthquake Engineering, CDROM, No.1931.
  10. Midorikawa, S., Matsuoka, M., and Sakugawa, K., 1994, Site effects on strong-motion records observed during the 1987 Chiba-ken-toho-oki, Japan, earthquake: Proceedings of the 9th Japan earthquake Engineering Symposium, 3, E085–E090.
  11. Nelson A. R. Personius S. F. Rimando R. E. Punongbayan R. S. Tungal N. M. Mirabueno H. Rasdas A. 2000 Multiple large earthquakes in the past 1500 years on a fault in Metropolitan Manila, the Philippines: Bulletin of the Seismological Society of America 90 73 85 10.1785/0119990002
    https://doi.org/10.1785/0119990002 [Google Scholar]
  12. Philippine Institute of Volcanology and Seismology, 2004, Earthquake Impact Reduction Study for Metropolitan Manila, Republic of the Philippines, Final report, 2.7–2.8.
  13. Satoh T. 2003 Identification of damping factors from vertical array data considering obliquely incident S-waves: Application of simulated annealing method: Journal of Structural and Construction Engineering 569 37 45
    [Google Scholar]
  14. Shibuya, J., 1983, Amplification of body waves, in Earthquake Motion and Ground Conditions: Architectural Institute of Japan, 98–105.
  15. Takemura M. Kato K. Ikeura T. Shima E. 1991 Site amplification of S-waves from strong motion records in special relation to surface geology: Journal of Physics of the Earth 39 537 552
    [Google Scholar]
  16. Yamada N. Yamanaka H. Takezono M. Kumada C. Baul-deocampo J. R. 2003 Simulation of strong ground motion in Metro Mamina, the Philippines: Journal of Structural Engineering. Architectural Institute of Japan 49B 1 6 [in Japanese]
    [Google Scholar]
  17. Yamanaka H. Nakamaru A. Kurita K. Seo K. 1998 Evaluation of site effects by an inversion of S-wave spectra with a constraint condition considering effects of shallow weathered layers:: Zisin (Journal of the Seismological Society of Japan) 51 193 202 [in Japanese with English Abstract]
    [Google Scholar]
  18. Yamanaka, H., Midorikawa, S., Kinugasa, Y., Bautista, B.C., and Rimando, R.E., 2002a, Estimation of Seismic Risk in Metro Manila, in Metro Manila, in Search of a Sustainable Future: University of the Philippines Press, 308–326.
  19. Yamanaka, H., Yamada, N., Takezono, M., Baul-deocampo, J. R., Kumada,C., Tiglao, R. B., Bautista, B. C., Takahashi, Y., and Samano, T., 2002b, Exploration of sedimentary layers in Metropolitan Manila, the Philippines, for estimation of site effects: Proceedings of the 11th Japan Earthquake Engineering Symposium, 323–328. [in Japanese with English abstract]
  20. Yamanaka H. 2005 Comparison of performance of heuristic search methods for phase velocity inversion in shallow surface wave methods: Journal of Environmental & Engineering Geophysics 10 163 173 10.2113/JEEG10.2.163
    https://doi.org/10.2113/JEEG10.2.163 [Google Scholar]
/content/journals/10.1071/EG11003
Loading
/content/journals/10.1071/EG11003
Loading

Data & Media loading...

Most Cited This Month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error