Seismic alarm system based on local seismicity and recent seismic past

A Seismic Alarm System for the Iberian Peninsula was proposed. Given the seismic situation of one zone, the seismic state for that zone and one time-window is computed. Two precursors were considered: • Initial conditions of the simulation model used to generate the process of occurrences on the Iberian Peninsula, describe the recent seismic past; • Local seismicity – number of occurrences of any magnitude – for a given zone and time-window. Fuzzy Set Theory was used to assess the alarm state of each precursor. A weighted average of the alarm state of each precursor is used to compute the global alarm state. The weights involved were computed using the AHP methodology – the percentages of predicted occurrences (or missed), false alarms and alarm life time were the criteria. Real seismic sets of data were used to calibrate the system.