Two large earthquakes occurred in the South Iceland seismic zone on June 17 and June 21, 2000, both of magnitude 6.6 (Ms). No short-term warning was issued before the first earthquake, although the sites of the two earthquakes were within 5 km of the location that had been estimated as most likely for the two next large earthquakes in the earthquake zone. This was mainly based on lack of release of moment in historical earthquakes in these two areas.
Short-term warning was issued 24 hours before the second earthquake, predicting the approximate size and the most likely area of maximum destruction within a kilometer. In hindsight very significant observations were also made before the first earthquake which may be very significant for warning in the future. The most significant observations of precursory activity were microearthquakes, water height or pressure in hot water boreholes, continuous GPS measurements and borehole strainmeters.
Warnings were issued by scientists at IMOR.DG. A fuller description is provided under Subproject 1.