Predictability test for pattern information method by two M_S7.3 Yutian, Xinjiang, earthquakes

In this paper， the Qinghai-Tibet tectonic block was chosen to be the study region， and calculating parameters with grid of 1°×1° were employed according to the previous studies by pattern informatics (PI) method for M7.0 earthquake prediction. Hotspot diagrams of each prediction window since 1993 have been obtained， and the relationship between the hotspots and the M>7.0 earthquakes during the prediction windows were studied. The predictability of PI method was tested by verification of receiver-operating characteristic (ROC) curve and R score. The results show that: ① Both of the Yutian M_S7.3 earthquakes in 2008 and in 2014 occurred in the region with the hotspots in the year with the highest average possibility. ② Nine earthquakes of M≥7.0 occurred in the retrospective studied period since 1993. Six of the nine earthquakes could be predicted by the successive obvious hotspots imagine， including the two Yutian M_S7.3 earthquakes; two of the nine earthquakes might be predicted because hotspots only occurred in a single predicted window without successive evolution process， including the Karakorum Pass M_S7.1 earthquake in 1996 and the Wenchuan M_S8.1 earthquake in 2008; one of the nine earthquakes， i.e.， Lijiang， Yunnan， M_S7.0 earthquake in 1996， could not be predicted because no hotspots appeared before the earthquake. The results associated with Wenchuan M_S8.0 earthquake in this paper are different from those of the previous studies， which may be caused by the differentce in selected study region and calculating parameters. ③ Test results of the predictability of PI method by ROC and R score show that positive prospect of PI method could be expected for long-term earthquake prediction. According to the calculating results based on the parameters from this study， three regions with high possibility for potential M7.0 earthquake risk in the future were given.