The frequency of earthquake occurrence in New Zealand

Abstract

Values of Gutenberg and Richter's constant b for the Main and Fiordland Seismic Regions of New Zealand based on the longest available sample of earthquakes are 0.96 ± 0.02 and 0.86 ± 0.08 respectively using the method of least squares, or 0.92 ± 0.07 and 0.68 ± 0.10 using maximum likelihood statistics to fit the data. The number of shocks of M_L ⩾ 4 per thousand km2 per decade is 5.7 and 5.6, but in the Main Region nearly half of them have focal depths greater than 100km. The frequency of occurrence of damaging shocks in Fiord1and is probably double that in the Main Seismic Region.