【摘要】 使用首都圈测震台网记录的地震波形资料，基于近震源Brune圆盘模型，计算唐山地区2009年1月至2024年12月2.5≤M_L≤2.9地震视应力，分析唐山地区M_S≥4.0地震前视应力时空分布特征。研究结果表明：时间分布显示，所选地震发生前，小震视应力多呈显著上升变化，显示出研究区域长时间处于高应力水平状态，地震多发生于视应力由高值转折下降后，这种转折变化预示了发震时间的紧迫性，发震模式反映了研究区域应力场的应力演变过程；空间分布显示，地震多发生在视应力高值集中区及附近，这些区域与应力增强区相对应，此空间分布特征对于判断未来主震的发生地点具有指示意义。更多还原

【Abstract】 Using the waveform data of small earthquakes recored by digital seismic network of the capital region, we calculated the apparent stress of 2.5 ≤ M_L≤ 2.9 earthquakes from January 2009 to December 2024 based on Brune model, analysised the temporal and spatial variation of apparent stress for earthquakes above M_S 4.0 in Tangshan area. The results show that: in terms of temporal distribution, the apparent stress of small earthquakes showed a significant upward trend before the occurrence of the selected earthquakes, indicating that the study area was in a state of high stress level for a long time. Earthquakes often occur after the apparent stress turned from a high value to a decreasing phase. The seismic mode reflects that the state of the stress field in the hypocenter region and the earthquakes occurred at the area which has large apparent stress gradients. which correspond to the stress enhancement process near the epicenter. This spatial distribution characteristic has indicative significance for judging the occurrence location of future main shocks.更多还原