From the article:..."Scientists have long sought forecasting methods for earthquakes, for obvious reasons—unfortunately, to date, little progress has been made despite hundreds of years of effort. Science has advanced one area of forecasting, however: aftershocks that occur after a major quake.
It has been noted that aftershocks can occur in sequences that frequently follow a power series. Because of that, seismologists could make predictions of aftershocks based on the degree of severity of the preceding major quake. But, as the researchers note, there are exceptions—sometimes, aftershocks seemingly occur randomly. Occasionally, they even precede a large quake. It was these exceptions that the researcher sought to address with a new and improved earthquake prediction system.