2015年7月3日新疆皮山M_S6.5地震前地震活动特征分析

ANALYSIS OF SEISMICITY CHARACTERISTICS OF PISHAN ERTHQUAKE WITH M_S6.5 ON JULY 3^(RD),2015

介绍2015年皮山M_S6.5地震周围的地质构造背景,研究分析了皮山M_S6.5地震前新疆地区中小地震活动和区域地震活动图像特征。结果表明:(1)皮山M_S6.5地震发生在2014年2月12日于田M_S7.3地震后,新疆地区中强地震处于弱活动状态下;(2)震前新疆地区3、4级地震出现了明显的"增强"活动现象;(3)震前震源区相关构造区域地震活动存在明显的4级地震平静、空区和5级地震空段等中期异常。以往震例显示,新疆地区6级以上地震前出现的中等地震平静、空区等异常图像具有普遍性,对新疆强震具有较好的震兆预测意义。

The paper introduces the geological structure background around Pishan earthquake with M_S6. 5 in 2015,analyzes the small earthquake activity and image features of regional seismicity in Xinjiang before Pishan earthquake with M_S6. 5. The results showed:(1) Pishan earthquake with M_S6. 5 happened after Yutian earthquake with M_S7. 3 on February 12 th,2014,the middle of strong earthquake in Xinjiang was in the state of calm.(2) Moderate earthquakes with magnitude 3. 0 and4. 0 in Xinjiang were in the state of bursting before this earthquake.(3) There were medium-term anomalies seismic activity in the regional geological structure around source area,such as the calm,seismogenic gap with M_S≥4. 0 and the earthquake empty segment with M_S≥5. 0. The previous earthquake cases before showed that moderate earthquakes calm and seismogenic gap of anomalies image usually appeared before the M_S≥6. 0,and that is very important to predict strong motion in Xinjiang.