Start: March 1996 (month 1)
End: September 1997 (month 19)
Responsible partner: NVI
Cooperative partners: CNRS.TT, IMOR.DG
General models have already been made and give some of the most interesting results obtained in Subpart 6B. The models indicate that stress migration is indicated schematically be the wave-like migration of the countours of constant shear stress as the loading of the fault zone (because of plate movements) is increased. The first contours to appear are those in the areas of highest shear stress concentration. As the loading (or displacement) is increased, however, these contours migrate over wider parts of the seismic zone, while the stress concentration in the initial high-stress "source"areas increases. The actual shear stress in the source areas does not become greater than the frictional equilibrium on faults in these areas allows; the stress is kept within these limits by repeated slip on many small faults. Because of increased loading, however, the regions where the shear-stress magnitude makes slip on faults possible gradually increases in size and depth, until the whole volume associated with the largest rupture area that the seismic zone is capable of generating is stressed to failure. These results offer the possibility of forecasting the largest earthquakes by detailed monitoring of the evolution of the seismicity in that zone.
Many of the results from Subpart 6B, including some of those indicated above, will be included not only in the scientific papers listed below, but also in the book: The Geology of Iceland and Mid-Ocean Ridges, that Gudmundsson is writing [31].