赣南及邻区视应力时空特征分析

利用赣南及邻区2009年以来的地震波形资料，计算249次M_L1.8~4.0地震的视应力，同时利用研究区1978年以来的地震目录计算b值。结果表明，视应力值在0.002~2.070 MPa之间，平均值为0.152 MPa；M_L2.0~2.9地震视应力的时间变化显示，2009年以来5次M_L≥3.5地震(去余震)中有3次震前出现高值异常，空间分布显示M_L≥3.0地震均发生在视应力高值区及高低值分界线附近；视应力与震级呈正相关关系；研究区1978年以来的最小完整性震级为M_L2.0，b值为0.78，2009年以来M_L≥3.0地震多发生在低b值区或其边缘附近；低b值区与视应力高值区分布较为接近，反映出较高的地震活动水平及地壳应力状态。

Analysis of Temporal and Spatial Characteristics of Apparent Stress in Southern Jiangxi and Its Adjacent Area

Using the seismic waveform data since 2009 in southern Jiangxi and its adjacent areas, wecalculate the apparent stress of 249 M_L1.8 to 4.0 earthquakes and calculate b-value using the earthquake catalogue since 1978. The results show that the apparent stress value is between 0.002 to 2.070 MPa, and the average value is 0.152 MPa. From the time variation of apparent stress with M_L2.0 to 2.9 earthquakes, three of the five M_L≥3.5 earthquakes (aftershocks removed) show high b-value anomalies since 2009. From the perspective of spatial distribution,M_L≥3.0 earthquakes occur in the region of high apparent stress and near the boundary between high and low values. The apparent stress is positively correlated with the magnitude. The minimum magnitude of completeness in the study area is M_L2.0 since 1978, and the b-value is 0.78; since 2009, most ofM_L≥3.0 earthquakes occur in the low b-value region or near the edge. The low b-value region is close to the high apparent stress region, which reflects the high seismicity and crustal stress state.