Abstract:
The Urad Rear Banner region is located at the intersection of the Alxa, Ordos, and Yanshan blocks. Seismic activity in this area is influenced by changes in the tectonic stress field and is correlated with the occurrence of moderate to strong earthquakes. Since October 2022, the region has experienced a significant increase in small earthquake activity, exceeding background levels. In this study, we analyzed a seismic window within the Urad Rear Banner area. The cumulative frequency of earthquakes with a magnitude of
M 2.0 or greater in 180 days was used as the window-opening indicator. The target events were earthquakes with
M≥5.0 events occurring along the northwestern edge of the Ordos block. Prediction effectiveness was evaluated using the
R-value metric. By examining the distribution of
R-values within the two-dimensional parameter space of the prediction window length and threshold, prediction rules were established based on the highest
R-value. The results showed that the highest
R-value was 0.43, with an optimal prediction window length of 200 days and an alarm threshold of eight events. Under these parameters, the frequency-based prediction indicator demonstrated good predictive performance and high reliability.