Nowcasting Earthquakes in North China

Abstract North China, a seismically active and densely populated region in East Asia, requires timely seismic risk assessment to enhance disaster preparedness and reduce potential impacts. This study employs an area–based earthquake nowcasting method to assess the current seismic cycle progression in 12 major cities across North China and its surrounding regions. We use the idea of natural times, the inter–event counts of small earthquakes between consecutive large events, to compute the Earthquake Potential Score (EPS) for each target city region. To determine the most suitable model for natural time statistics, we evaluate eight probability distributions. Statistical analysis of 25 observed natural times reveals that the exponential model best represents the data. As of March 25, 2025, EPS values for M ≥ 6.0 earthquakes range from 32 to 84%, with the highest score observed in Dalian (84%), followed by Beijing (76%), Tianjin (70%), Shenyang (67%), Tangshan (67%), Hangzhou (66%), Dezhou (66%), Jinan (57%), Hohhot (44%), Nanjing (35%), Haicheng (33%), and Shanghai (32%). These values reflect the progression of each city in its current seismic cycle toward a future M ≥ 6.0 event. This study not only provides critical information to enhance seismic hazard mitigation but also promotes data–driven earthquake preparedness strategies for the region.