GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 2.1 GNGTS 2023 Fig. 1. The correlation histogram retrieved by CEs of strong East Pacific earthquakes in coincidence with high energy electron bursts detected by NOAA-15 satellite from July 1, 1998, up to December 31, 2014. The horizontal dashed line in black represents the average while the horizontal dashed line in red represents the 3-sigma level corresponding to a probability of 1% that a peak occurred by chance. The geographical region where EQs correlated with NOAA-15 EBs is delimited by − 40° to 30° in latitude and by 245° to 300° in longitude, so including regions where strong seismic activity occurs. Interested countries were Mexico, the Caribbean Sea, Guatemala, Honduras, Nicaragua, Costa Rica, Panama, Columbia, Ecuador, Perú, Bolivia, Chile, and a large part of the South-eastern Pacific. To use this result with a risk reduction objective, for example for tsunami hazards, a scenario needs to be defined (Console, 2001). The scenario was defined by the target volume VT where EQs occur, which is a three-dimensional space of latitude × longitude × time. The scenario in East Pacific was reported by a black contour in Figure 2, where EQ epicenters of the correlation result were indicated by red points and the EQ occurrence was indicated by red stars. If an EQ occurs in the alarm volume VA in red, it is a success (S), while if an EQ occurs out of the red volume it is a failure of prediction (F). The precursor volume VP contains the EBs that are alarm events. In this case, VP is indicated in cyan. The EB detection defines a VA. The period of the EQ observations multiplied by the area of East Pacific where the correlations in Figure 1 are calculated is VT. Differently from the West Pacific case, EQs and EBs areas largely overlap in this scenario. VA's height is the correlation bin's time, and VA covers the same area as VT.