# The Conditional Probability of Correlating East Pacific Earthquakes with NOAA Electron Bursts
## 3 Results  
The extraction of EBs from the NOAA-15 database of CRs starting from July 1998 to December 2014 was performed using the same procedure as in previous analyses [26; 27; 28]. Being so, the starting set of EBs to correlate to EQs remained unvaried and is reported in Figure 2 of a past work [28]. These EBs were all in the loss cone with bouncing altitudes lower than 200 km, and for 95% of cases lower than 100 km, in correspondence to the South Atlantic Anomaly (SAA). Figure 1 reports the geographical distribution of the NOAA-15 trajectories in one day, where the electron flux distribution along the trajectory is represented in colors. The black contour in the center represents the SAA. As reported in previous analysis, see, for example, Figure 1 of [26], precipitating electrons were observed far from the SAA to the west up until 170\({}^{\circ}\) in longitude, indicated by the cyan contour of Figure 1. The space-time distribution of the detected EBs consists of a series of consecutive events corresponding to time intervals lasting up to a few minutes. Although, one or more non-consecutive detections characterized the space-time distribution of EBs along the single semi-orbit. Moreover, the observation of one or more EBs in a semi-orbit was defined as only an EB event. Being that the EB L-shells were limited at L \(<\) 1.4 by the requirements of precipitating particles from the inner Van Allen Belts, the time length of every EBs was always found less than 12 min. For what concerns the EB time, was defined as the average time among the times of selected EBs in the semi-orbit. Unlike the previous study [26], which investigated strong EQs worldwide, the subsequent work [28] reported on correlations obtained with EQs restricted to the Philippines and Indonesian areas, in order to maximize the ratio between the correlation amplitude and the non-correlation amplitude. Afterward, numerous geographical areas were tested for their suitability, with the aim of maximizing this ratio, so a stronger correlation was obtained for West Pacific EQs [27]. During our study, the extension of the EQ area was pushed to the Central Pacific until it reached the East Pacific, therein another correlation peak emerged. Given this, a new analysis started  
Figure 1: The set of NOAA-15 semi-orbits on 4 January 2001, with the CRs along the line orbits evidenced by colors; CR = 0 in blue, CR = \(10^{0}\) in light blue, CR = \(10^{1}\) in green, CR = \(10^{2}\) in orange, and CR = \(10^{3}\) in yellow; the SAA region is evidenced using a black contour, while the region where the satellite detect electrons in the loss cone, is evidenced by a cyan contour. A set of 6 correlation plots between 30-100 eV EBs and East Pacific M \(\geq\) 6 EQs are shown in Figure 2 where the bin time interval was chosen between 2 and 6 h. A range of \(\pm\)3 days was considered for the time difference between EQs and EBs, where \(\mathrm{T_{EQ}-T_{EB}}\) positive highlights that EBs precede EQs, while EQs precede EBs for negative time differences. CE distributions were Poissonian as in past cases, and the average values are indicated using black dashed lines, while the red dashed lines are used for standard deviations. Significant correlation peaks appear at time differences around 57 h, which means that the EB observation anticipated the corresponding EQ. Unlike past works [26; 28], where the correlation significance was represented by EQ projections at certain altitudes, here the correlation significance was calculated exclusively with respect to the EB features. In analogy with the case of West Pacific EQs [27], the L-shell interval of electrons to maximize the correlations between EBs and East Pacific EQs was obtained at 1.1 \(\leq\) L \(\leq\) 1.3. A plot of this EB L-shell parameter compared to latitudes is shown in Figure 3. The plot reports two distinct distributions, a correlation for negative latitudes and a lack of correlation for positive ones.