Modelling ground motion in the Hutt Valley, New Zealand
DOI:
https://doi.org/10.5459/bnzsee.40.4.190-199Abstract
The Hutt Valley is an alluvial basin that hosts the city of Lower Hutt, in the North Island, New Zealand. The basin is bounded by the Wellington Fault on its northwest side, and exhibits ground motion amplification factors up to about 15, measured by several seismic experiments using weak motion and portable seismic arrays during 1990-1991. Synthetic seismograms computed by using local 1D stratigraphic models under each station reproduce qualitatively the amplitudes and durations of the corresponding observed seismograms at most of the soft site stations of the arrays. Amplification factors estimated from spectral ratios of the synthetic seismograms are up to about 9. The authors present comparisons of amplification between synthetics and observations, allowing a “calibration” of the model so that it could be used to determine more realistic ground amplifications for earthquake scenarios.
References
Adams, B.M., Osborne, N. and Taber J.J. (2003), “Basin Edge Effect from Weak Ground Motions Across the Fault Bounded Edge of the Lower Hutt Valley, New Zealand”, Bulletin of the Seismological Society of America; 93(6): 2703-2716. DOI: https://doi.org/10.1785/0120010277
Benites, R. and Olsen, K.B. (2005), “Modelling Strong Ground Motion in the Wellington Metropolitan area, New Zealand”, Bull. Seismol. Soc. Am.; 95(6): 2180-2196. DOI: https://doi.org/10.1785/0120040223
Ben-Menahem, A. and Singh, S.J. (1981), “Seismic waves and sources”, Springer-Verlag, New York, USA, 1108 pp. DOI: https://doi.org/10.1007/978-1-4612-5856-8
Borcherdt, R.D. and Glassmoyer, G. (1992), “On the characteristics of local geology and their influence on ground motions generated by the Loma Prieta earthquake in the San Francisco Bay region, California”, Bull. Seimol. Soc. Amer.; 82: 603-641.
Bouchon, M. and Aki, K.(1977), “Discrete wavenumber representation of seismic source wave fields”, Bull. Seismol. Soc. Am.; 67: 259-277.
Coutel, F. and Mora, P. (1998), “Simulation-based comparison of four site-response estimation techniques”, Bull. Seismol. Soc. Am.; 88: 30-42.
Hays, W.W. and Gori, P.L. (1983), “A Workshop on The 1886 Charleston, South Carolina, Earthquake and Its Implications for Today”, USGS, Open-File Report 83-843. DOI: https://doi.org/10.3133/ofr83843
Hartzell, S., Cranswick, E., Frankel, A., Carver, F. and Mermonte, M. (1997),“Variability of site response in the Los Angeles Urban area”, Bull. Seismol. Soc. Am.; 87: 1377-1400.
Kawase, H., (1996). “The cause of the damage belt in Kobe: ‘the basin edge effect’, constructive interference of the direct S-wave with the basin induced diffracted Rayleigh waves”, Seis. Research Lett.; 67: 25-34. DOI: https://doi.org/10.1785/gssrl.67.5.25
Kawashima, K., Aizawa, K. and Takahashi, K. (1986), “Attenuation of peak ground acceleration, velocity and displacement based on multiple regression analysis of Japanese strong motion records”, Earthquake Engineering and Structural Dynamics; 14: 199-215. DOI: https://doi.org/10.1002/eqe.4290140204
Kennett, B.L.N. (1983), “Seismic Wave Propagation in Stratified Media, Cambridge Monographs on Mechanics and Applied Mathematics”, Cambridge University Press, Cambridge, UK, 342 pp.
Lay, T. and Wallace, T. (1995), Modern Global Seismology, Academic Press, San Diego, USA, 521 pp.
Ma, S.Q. (2004), “Calibration of Wellington 3D model”, MSc thesis, Institute of Geophysics, Victoria University of Wellington, New Zealand, 163 pp.
Matcham, I., Savage, M.K., Taber, J.J. and Reyners, M.E. (2006), “Earthquake source mechanism analysis for events between 1992 and 1997 using sparse New Zealand broadband data”. New Zealand Journal of Geology and Geophysics, 49(1): 75-89. DOI: https://doi.org/10.1080/00288306.2006.9515149
Nagano, M. (1998), “Amplification characteristics of the ground motions in deep irregular underground structure with vertical discontinuity”, Proc. 2nd Intl. Symposium on the Effects of Surface Geology on Seismic Ground Motion, Yokohama, Japan: 859-866.
Robinson, R. (1986), “Seismicity, structure and tectonics of the Wellington region, New Zealand”, Geophys. J. R. Astr. Soc.; 87: 379-409. DOI: https://doi.org/10.1111/j.1365-246X.1986.tb06629.x
Schwartz, S.Y. (1995), “Source parameters of aftershock of the 1991 Costa Rica and 1992 Cape Mendocino, California earthquake from inversion of local amplitude ratio and broadband waveforms”, Bull. Seismol. Soc. Am.; 85: 1560-1575.
Seed, H.B., Romo, M.P., Sun, J.I., Jaime, A. and Lysmer, J. (1988), “The Mexico earthquake of September 19, 1985-relationship between soil conditions and earthquake ground motions”, Earthquake Spectra; 4. DOI: https://doi.org/10.1193/1.1585498
Sritharan, S. and McVerry, G.H. (1992), “Microzone effects in the Hutt Valley in records from a strong motion accelerograph array”, Bull. of the New Zealand National Society for Earthquake Engineering; 25: 246-264. DOI: https://doi.org/10.5459/bnzsee.25.4.246-264
Van Dissen, R.J., Taber, J.J., Stephenson, W.R., Sritharan, S., Read, S.A.L, McVerry, G.H., Dellow, G.D. and Barker, P.R. (1992), “Earthquake ground shaking hazard assessment for the Lower Hutt and Porirua areas”, Bull. of the New Zealand National Society for Earthquake Engineering; 25: 286-302. DOI: https://doi.org/10.5459/bnzsee.25.4.286-302
Taber, J.J. and Smith, E.G.C. (1992), “Frequency dependent amplification of weak ground motions in Porirua and Lower Hutt, New Zealand”, Bull. of the New Zealand National Society for Earthquake Engineering; 25(4): 303-331. DOI: https://doi.org/10.5459/bnzsee.25.4.303-331
Yu, J. and Haines, J. (2003), “The choice of reference sites for seismic ground motion amplification analysis: case study at Parkway, New Zealand”. Bull. Seismol. Soc. Am., 93(2): 713-723. DOI: https://doi.org/10.1785/0120010289
