Stress Drop Variations in New Zealand Using Empirical Green's Function

Determine source parameters (stress drop, radiated energy, rupture velocity) for moderate size Earthquakes from different settings of New Zealand. There are four distinct areas where large earthquakes have large aftershock sequences or swarm sequences which provides numerous moderate magnitude events that will allow the use of an empirical green’s function (EGF) approach to analyze the source processes. I propose to use a single analysis technique for data recorded by a single network to determine stress drops for earthquakes in four very different tectonic settings in New Zealand. The Four areas of interest that will be explored are the Hikurangi subduction zone, Taupo Volcanic Zone (TVZ), Alpine strike-slip fault in the South Island, and the Puysegur/Fiordland subduction zone in the south. I propose to examine four earthquake sequences located in diverse tectonic regions of New Zealand in order to determine the level of uncertainty related to the empirical green function technique.  I also propose to distinguish the differences in source parameters between the 4 regions of interest.  Important questions could be addressed about the regional stress variation within New Zealand using the empirical green function technique. It is expected that there are significant differences in stress drops and other source parameters in the four areas of interest and this will help to validate the reasoning behind using the empirical green’s function approach.