# The Conditional Probability of Correlating East Pacific Earthquakes with NOAA Electron Bursts
## 4 Discussion
Case studies based upon data from the DEMETER satellite of East Pacific EQs, such as the Chile EQ M = 8.8 on 27 February 2010, and the Haiti EQ M = 7.0 on 12 January 2010, recorded similar delays with electron detections [34], also associated with VLF wave activity. Preparedness for strong EQs and tsunamis has been developed over recent decades [35] either by triggering early warnings or by rapidly assessing the expected damages [36]. Early warnings consist of alerts seconds before the arrival of destructive seismic waves in populated regions. Such an alert may be useful in controlling the shutdown of gas pipelines and critical facilities, reducing speeds of rapid-transit vehicles, and also advising the interested populations to follow the necessary precautions. Reduced lead times limit the possible preparedness actions, thus leaving part of the population at the mercy of imminentdanger. Utilizing the possible correlation results obtained above for a short-time warning in strong EQs and tsunami preparedness might contribute to reducing the impact of EQs. A way of using such results is to define a scenario for a short-time prediction model [27]. Following the work of [PERSON] [37], the representation of the EQ prediction model would need to define the target volume where EQs occur \(\mathrm{V_{T}}\), which is a 2-d geographic space + 1-d time-space. This volume is displayed by a black contour in Figure 8, and with EQs occurrence by red stars. If an EQ occurs in the alarm volume \(\mathrm{V_{A}}\) in yellow, it is a success (S), while if an EQ occurs out of the yellow volume it is a failure of prediction (F). The precursor volume \(\mathrm{V_{P}}\), which is generally different from \(\mathrm{V_{T}}\), contains the alarm events. In this case, \(\mathrm{V_{P}}\) is the cyan volume of Figure 8 where EBs are detected, the time of EB observations lasting less than 12 min. When an EB is detected in \(\mathrm{V_{P}}\) it is an alarm that defines a \(\mathrm{V_{A}}\). The time span of the EQ observations multiplied by the area of East Pacific where the correlations in Figure 2 are calculated is \(\mathrm{V_{T}}\). An EQ event is included in this scenario only if \(\mathrm{M}\geq 6\). Unlike West Pacific earthquakes where geographical areas of \(\mathrm{V_{P}}\) and \(\mathrm{V_{A}}\) were completely disjoined, areas of EQs and EBs are largely overlapping in this scenario. In this representation, \(\mathrm{V_{A}}\) has the dimension T which coincides with the correlation bin dimension, it is generated by an EB detection in \(\mathrm{V_{P}}\), and covers the same area as \(\mathrm{V_{T}}\). To have the greatest significance the 4 h bin interval of 54.3-58.3 h should be chosen. The \(\mathrm{V_{A}}\) dimension and shape are the same for each detected EBs in \(\mathrm{V_{P}}\); if an EQ with \(\mathrm{M}\geq 6\) occurs in \(\mathrm{V_{A}}\) one success is collected. Similarly, if an EQ occurs out of the \(\mathrm{V_{A}}\), meaning that it happened before or after the 4 h between the 56.3 h following the EB, one failure is collected. Moreover, one false alarm is collected for any EB detection not followed by any EQ. Non-continuous \(\mathrm{V_{T}}\) is defined as when the Sun's activity leads to discarding days or due to the NOAA-15 satellite intermittence into the detection area west of the SAA. A \(\mathrm{V_{A}}\) is generated within \(\mathrm{V_{T}}\) 56.3 h after an EB is detected in \(\mathrm{V_{P}}\), and the time ahead is the vertical distance in the representation of Figure 8.  
Figure 8: The scenario is the volume representation where a forecasting model can be tested, here it is delimited by the target volume \(\mathrm{V_{T}}\), the alert volume \(\mathrm{V_{A}}\), and the precursor volume \(\mathrm{V_{P}}\), the latter two being products among the geographical coordinates of EQs and EBs and the time of observations. Discontinuities in time are due to the solar activity intermittence. The alarm duration can be chosen to be 4 h in this work which corresponds to the greatest significance.