Critical parameter estimates for earthquake forecast using PI migration

Parameters usually play a key role in statistical forecasting models and should be carefully determined because the physics of the system links to the statistical model through the parameters. To investigate the relations between parameters and pattern informatics (PI) migration, we developed a series of retrospective analyses. The results show that two parameters (i.e., cut magnitude and change interval) are essential factors of calculating PI migration. The cut magnitude is a lower cutoff magnitude applied to the catalog at the start of the analysis, and the result of the analysis shows that the PI migration hot spots are mostly distributed around the earthquakes with magnitude larger than target magnitude when the cut magnitude is 3.2–3.4 in most study regions. The change interval is a time span prior to the large event that we assumed to be the duration of the preparation process. In the retrospective analysis, the ability of PI migration hot spot to hit the target earthquake varies with change interval and the change interval that make PI migration hot spot to hit most target earthquakes varies with the study region. By using a retrospective analysis, we determined the optimal parameters for each study region, generating PI migration maps to show potential locations.