D49 Method and user guidelines for combining geodetic, seismic results in hazard assessments – NVI

The final outcome here is based on the results of WP4130 and WP 3100 which are well advanced. Work is going on towards estimating in time and space the stress tensors in the area based on microearthquakes. The basic data here are the microearthquake catalogues for the areas under study. The main area under study is the Hengill (seismo-volcanic) area, where high swarm activity took place during 1994-1998, culminating in a tectonic event on a 10 km long NS fault during June to November 1998, largest earthquakes around magnitude 5. Data and results of ongoing research in the South Iceland seismic zone (SISZ) will also be applied here. The SISZ suffered two magnitude 6.6 (Ms) earthquakes In the year 2000 with huge aftershock activiy covering all the SISZ area and the Reykjanes peninsula to the west of it. The completed microearthquake catalogue covering these periods, i.e. from 1991, was made available for further research work by IMO in September 2003. This catalogue consists of high level parameter information from 170 thousand earthquakes and wave form data which can render information for fault mapping and stress tensor inversions over the whole area under study, including pre and post earthquake period. Some parts of this catalogue have been evaluated for stress tensor inversions and fault mapping (see WP 3100). However work is ongoing by IMO and others on extracting this information from the catalogue as a whole. The combination of the new geodetic and seismic methods to advance the time independent and time dependent assessments based on older methods has not yet come to an end. It is expected that significant results for such advancements can be reported in 12 months time.