Seismic microzoning in New Zealand

  • W. R. Stephenson DSIR Physics and Engineering Laboratory, Lower Hutt, New Zealand


"Seismic Microzoning" means many different things to different people. There is always included the element of different damage in nearby areas, but how the differences arise, how we should study them, and how we should apply the results of our studies, are still uncertain.

To some people, microzoning refers to structural damage due to ground failure; faulting, slumping and liquefaction all belong in this category. To others, microzoning is the effects of the focussing of seismic waves by boundaries, resulting in modified ground damage and building damage.

A third very popular view of microzoning holds that it concerns multiple reflection of seismic waves in layers, with interference of the wave trains giving rise to maxima, where ground and structural damage will be accentuated.

Microzoning can be defined as the division of land areas into small regions of differing local geology for which differences in earthquake attack on structures are specified.

This paper is an attempt to set down aspects of microzoning in a logical manner, and to relate them. It also discusses activities here and overseas, and considers where microzoning and microzoning research in New Zealand should head.

How to Cite
Stephenson, W. R. (1971). Seismic microzoning in New Zealand. Bulletin of the New Zealand Society for Earthquake Engineering, 4(1), 43-50.