Differences in time terms between New Zealand seismograph stations and implications for crustal structure

Abstract

Differences between time terms roughly equal to the crustal contributions to Pn and Sn travel times have been calculated for pairs of stations of the New Zealand seismograph network. The maximum differences found between 2 stations are 2.6 s for P-waves and 6.8 s for S-waves. These differences reflect major differences in crustal structure and, although they cannot be interpreted unambiguously in terms of crustal thickness and/or crustal seismic wave velocities, they provide important constraints on structure not evident from surface geology. The results will ultimately be important in improving the accuracy of local earthquake locations.