Task 4: Mobile stations for shear-wave splitting monitoring

The objective of this task is to investigate more in detail the shear-wave splitting effects of the crust and the spatial distribution of the observed anisotropy. Seven three-component mobile seismometers of ORION type were borrowed for this purpose from UUPP.DGEO. The seismometers were operated as a dense network near to the SIL station SAU for this purpose, from May 13 to July 5, 1998, and again from July 23 to August 13. This is in the middle of the South Iceland seismic zone and it is very significant for future use of shear-wave splitting methods in this earthquake-prone area to carry out this study. Data were collected for this period and preparations are going on to evaluate these data. It has taken some work to merge these data with the SIL data evaluation system algorithms. This is necessary for best results, and so the high level evaluation processes of the SIL system can be utilized in full. Work on this task is ongoing, but the enormous seismic and volcanic activity in southern Iceland during the last two years has delayed this work as it has been considered more significant to save and to evaluate data of the recent large hazard events.