GNGTS 2018 - 37° Convegno Nazionale

346 GNGTS 2018 S essione 2.1 interest to the physical process which could be the link between earthquakes and electron bursts. The physical interaction consists in magnetic fluctuations coupled with charged particles which are able to modify pitch angles of electron motions inside the Van Allen Belts. Pitch angle variations generate variations in bouncing altitudes of charged particles, with a consequent presence of greater fluxes of electrons at satellite altitudes. However, the correlation above regarding earthquakes which occurred in the Indonesian and Philippine Regions are located at different geographical coordinates with respect to those where electrons were detected by NOAA. These different positions could have been associated in a causal way, due to the fact that electrons drift eastwards and the earthquake epicentre positions were located west of the electron burst detection positions. In turn, if any kind of disturbances above the earthquake epicentres occurred, it would have perturbed electrons motions and thus electron bursts would have been detected some time after, see Figure 2. This implicates that, if magnetic pulses are able to reach the ionosphere, they anticipated the earthquake times by 4 – 6.5 hours. This time interval was obtained considering energy corrections at NOAA detectors (Yando et al., 2011) and is a reduced interval with respect to those previously calculated of 4 – 10 hours (Fidani, 2015). If such a causal connection exists between earthquakes and electron bursts, a question can be raised: could the 2 - 3 hours correlation be used for strong earthquake forecasting? The answer to this question can be positive if the probability calculation of a strong earthquake over the next 2 - 3 hours refers to Indonesia or the Philippines. The conditional probability of an earthquake event EQ given an electron burst event EB P (EQ|EB) = P (EQ ∩ EB)/ P (EB) (1) can be calculated throughout the relation between covariance and cross correlation (Fidani, 2018) P (EQ|EB) = P (EQ) + corr (EQ,EB)√ P (EQ)[1− P (EQ)][1− P (EB)]/ P (EB). (2) The relation between covariance and correlation applied to earthquake and electron burst unitary events can be rewritten in: corr (EQ,EB) = cov (EQ,EB) /√P (EQ)[1− P (EQ)] P (EB)[1− P (EB)], (3) Fig. 2 - A possible physical model to causally connect earthquakes in Indonesian and Philippines and electron burst observations. Dimensions of the Inner Van Allen Belts are not in scale to obtain a clearer representation of electron burst dynamics. The image was modified from the NASA animation downloaded at https://www.nasa.gov .