2014 年2 月12 日新疆于田MS 7. 3地震前地震活动特征分析

The analysis of the seismicity characteristics of the Yutian MS 7. 3 earthquake on February 12，2014

摘要:

介绍了2014 年于田MS7. 3 地震周围地质构造背景，研究分析了MS7. 3 地震前新疆地区中小地震活动状态以及区域地震活动图像特征，并与2008 年于田MS7. 3 地震前区域地震活动特征进行了对比分析。结果表明:①本次于田MS7. 3 地震前2 ～ 3 年新疆地区处于中强地震连发活动状态，震前出现明显的3、4 级地震平静状态;②MS7. 3 地震前，区域地震活动存在中短期异常特征，即MS7. 3 地震前3 年，阿尔金地震带及震源区周围5 级以上地震活动增强显著，而震源区东侧440km 范围内4 级地震出现长达5 年的平静状态;MS7. 3 地震前半年，震区附近出现了3、4 级地震孕震空区和近乎共轭分布的3、4 级地震密集条带异常图像;③本次MS7. 3 地震前，新疆地区中强地震活动状态、中小地震活动异常图像均与2008 年于田地震前存在较明显的差异，这可能与2 次7 级地震的孕震环境存在差异有关。

Abstract:

The paper introduces the geological structure background around the Yutian MS 7. 3 earthquake，analyzes the small earthquake activity and image features of regional seismicity in Xinjiang before the MS 7. 3 earthquake，and compares the image features of regional seismicity with the MS7. 3 earthquake in Yutian，in 2008． The results showed: ① 2 ～ 3 years before the Yutian MS7. 3 earthquake，Xinjiang was in the state of strong earthquake bursting，and before the MS7. 3 earthquake，moderate earthquakes with magnitude 3. 0 and 4. 0 in Xinjiang were in the state of calm． ② Before the Yutian MS 7. 3 earthquake，there showed short-term anomalies in regional seismic activity． 3 years before this MS7. 3 earthquake，the earthquakes with MS≥5. 0 in the Altun earthquake zone and source area significantly enhanced，but the earthquakes with MS≥ 4. 0 in the east side of the source area for about 440km appeared up to 5 years of calm． Six months before the MS 7. 3 earthquake，there appeared a seismogenic gap of earthquakes with magnitude 3. 0 and 4. 0 in the source area and dense bands abnormal image of earthquakes with MS3. 0 ～ 4. 0 that almost conjugate distribution． ③ Before the earthquake with MS 7. 3，strong seismicity status and small earthquakes abnormal images in Xinjiang were significantly different with MS7. 3 earthquake in 2008． This may be related with the seismogenic environment of the two MS7. 0 earthquakes．