Earthquake Forecast Verification for Northwestern Turkey

Abstract

Seismic events have a pattern of recurrence in magnitude, time and space. Considerable effort is being spent to identify seismic patterns and successfully predict future earthquakes by using the recognized patterns. As a result of these intensive efforts, a variety of methods has been proposed. As the knowledge and experience in the field accumulated in parallel to the variety of the methods proposed, it was deemed necessary to test the performance of some of the highlighted methods, especially considering the wide reception of methods utilizing spatially smoothed seismicity (SSS), pattern informatics (PI) and Relative Intensity (RI). The performance of these methods in the prediction of future earthquakes has been selected for investigation. The investigated area is the region bounded by 270-330 in longitudes and 39.80-410 in latitudes, well known for the North Anatolian Fault. The period of coverage has been selected such as to maximize the length with the minimum magnitude of completeness. As a result of such optimization, the period from 1973 to 2019 has been selected with minimum magnitude of completeness being determined as 3.8. In order to measure the relative performance of the methods, relative operating characteristic (ROC) analysis has been utilized. The method based on SSS has been adapted to the related ROC procedures, while the results of PI and RI methods are already suitable for the evaluation by ROC procedures. After the analysis was completed, according to the ROC procedures, none of the methods were singled out in forecast performance. However, when the ratio of hits versus total alarms and the area covered by the alarms, PI method outperforms two other methods by its efficiency.