Risk of casualties in New Zealand earthquakes

Abstract

This paper reports on a study of all earthquakes that have caused (or could have caused) casualties in New Zealand in the period 1840-2003 inclusive. The intensity which has been the effective threshold for injuries is Modified Mercalli intensity VII (MM7). In the period of interest at least 73 earthquakes of magnitude Mw ≥ 5 have caused MM7 or greater in populated areas, and of these events 16 have caused direct casualties, 297 deaths and 640 hospitalized injured. The causes of the casualties are tabulated and discussed, and the potential to reduce casualties in the future is assessed, in particular in a large earthquake on the Wellington fault. Death rates have been determined empirically as functions of four types of structure and MM intensity.