A model for MM intensities near large earthquakes

Authors

  • Warwick D. Smith GNS Science, Lower Hutt, New Zealand

DOI:

https://doi.org/10.5459/bnzsee.35.2.96-107

Abstract

The attenuation model for Modified Mercalli intensities that is currently in use in New Zealand (Dowrick & Rhoades, 1999) was developed from the available intensity data from large local earthquakes in New Zealand, but it does not represent well the intensity patterns that are expected when large earthquakes occur on long faults (length 20 km or more). This is because very few such events have occurred in New Zealand in historical times.

An attempt to account for elongated source geometries has resulted in a model which provides a plausible extension to the Dowrick & Rhoades model. It also addresses detail in the intensity data from New Zealand's four largest historical earthquakes, that has not previously been accounted for.

In development of the new model, stochastic terms have been added to represent the effects of asperities or areas of large slip on the rupture surface and to account for uncertainty in the fitting of the original data.

References

Darby, D.J. & Beanland, S. 1992. Possible source models for the 1855 Wairarapa earthquake, New Zealand. Journal of Geophysical Research 89, 12375-12389.

Doser, D.I., Webb, T.H. & Maunder, D.E. 1999. Source parameters of large historical (1918-1961) earthquakes, South Island, New Zealand. Geophysical Journal International 139, 769-794.

Doser, D.I. & Webb, T.H. (In prep). Source parameters of large historical (1917-1961) earthquakes, North Island, New Zealand.

Dowrick, D.J & Rhoades, D.A. 1999. Attenuation of Modified Mercalli intensity in New Zealand earthquakes. Bulletin of the New Zealand Society for Earthquake Engineering 32, 55-89.

Smith, W.D. 1978. Spatial distribution of felt intensities for New Zealand earthquakes. New Zealand Journal of Geology and Geophysics 21, 293-311.

Smith, W.D. 1990. Earthquakes hazard in New Zealand: some implications of the Edgecumbe earthquake, March 1987. Bulletin of the New Zealand National Society for Earthquake Engineering 23, 211-219.

Smith, W.D. 1995. A procedure for modelling near-field earthquake intensities. Bulletin of the New Zealand National Society for Earthquake Engineering 28, 218- 223.

Stirling, M., McV erry, G., Berryman, K., McGinty, P., Villamor, P., Van Dissen, R., Dowrick, D., Cousins, J. and Sutherland, R., 2000. Probabilistic seismic hazard assessment of New Zealand: new active fault data, attenuation relationships and methods. Client Report 2000/53, Institute of Geological and Nuclear Sciences Ltd, May 2000, prepared for Earthquake Commission Research Foundation.

Takemura, M. & Ohno, S. 1996. A new distance measure for the attenuation curve. Proceedings of the International Workshop on Site Response Subjected to Strong Earthquake Motions, Yohosuka, Japan, January 16-17, 1996.

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Published

30-06-2002

How to Cite

Smith, W. D. (2002). A model for MM intensities near large earthquakes. Bulletin of the New Zealand Society for Earthquake Engineering, 35(2), 96–107. https://doi.org/10.5459/bnzsee.35.2.96-107

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