| 九寨沟M_S7.0地震地电阻率变化时空演化分析 |
| |
| 引用本文： | 王同利,崔博闻,叶青,李菊珍,王丽红,童琼.九寨沟M_S7.0地震地电阻率变化时空演化分析[J].地球物理学报,2020,63(6):2345-2356. |
| |
| 作者姓名： | 王同利 崔博闻 叶青 李菊珍 王丽红 童琼 |
| |
| 作者单位： | 1. 北京市地震局, 北京 100081;2. 中国地震台网中心, 北京 100045;3. 湖南省地震局长沙地震台, 长沙 410012 |
| |
| 基金项目： | 中国地震局震情跟踪面上项目（2020020403），中国地震实验场项目（2019CSES0113）及冬奥会保障晋冀蒙监测能力提升项目资助. |
| |
| 摘 要： | 本文应用归一化变化速率(NVRM)方法,研究了2017年九寨沟M_S7.0地震周边800km范围内25个地电阻率台站2012—2018年的连续观测数据,分析了震中区周围的地电阻率时、空演化过程.结果显示:(1)25个台站中共有14个台站在震前出现了地电阻率变化,结合本次地震震源机制等分析其时空变化,认为邻近地震破裂带的临夏、通渭、武都和宝鸡台地电阻率在震前出现了下降—折返回升型的变化,符合前人已总结的强地震前地电阻率的变化过程.(2)地震发生前震中区周围大区域内出现了地电阻率负异常变化,且以震中区为中心呈条带分布,异常区的长轴方向与地震断裂带走向或地震烈度分布的长轴方向几乎垂直,与地震主压应力轴方向吻合.本文认为九寨沟M_S7.0强震发生之前,震中区周围出现的区域性地电阻率异常空间丛集现象是很好的中期和短临前兆;地电阻率震前异常动态演化、各向异性等特征对认识本次强震发震断层活动以及震源区应力场分布有启示意义.
|
| 关 键 词： | 九寨沟地震 地电阻率 时空分布 异常变化 震源机制 |
| 收稿时间： | 2019-12-31 |
Temporal-spatial distribution of apparent resistivity before and after the Jiuzhaigou MS7.0 earthquake |
| |
| WANG TongLi,CUI BoWen,YE Qing,LI JuZhen,WANG LiHong,TONG Qiong.Temporal-spatial distribution of apparent resistivity before and after the Jiuzhaigou MS7.0 earthquake[J].Chinese Journal of Geophysics,2020,63(6):2345-2356. |
| |
| Authors: | WANG TongLi CUI BoWen YE Qing LI JuZhen WANG LiHong TONG Qiong |
| |
| Institution: | 1. Beijing Earthquake Agency, Beijing 100080, China;2. China Earthquake Networks Center, China Earthquake Administration, Beijing 100045, China;3. Hunan Earthquake Agency, Changsha 410012, China |
| |
| Abstract: | The Jiuzhaigou MS7.0 earthquake occurred in Sichuan Province on August 8, 2017. In this paper, data collected from a total of 25 stations distributed within ~800 km of the epicenter of the Jiuzhaigou MS7.0 earthquake from 2012 to 2018,were used to investigate the temporal-spatial evolution of apparent resistivity by applying the Normalized Variation Rate Method (NVRM). The results are as follows: (1) Apparent resistivity anomalies were observed at 14 stations around the epicenter before the earthquake. Combining with the focal mechanism analysis, we suggested that the temporal spatial variation of apparent resistivity observed at Linxia, Tongwei, Wudu and Baoji stations adjacent to the earthquake rupture zone was consistent with the development of apparent resistivity anomaly associated with the mechanism of earthquake. (2) Negative abnormal changes of apparent resistivity occurred in a large area and were featured with a two-quadrant distribution pattern around the epicenter before the earthquake. The long axis direction of the area with apparent resistivity anomaly was nearly perpendicular to the direction of the earthquake rupture, the fault strike, and the long axis direction of the earthquake intensity distribution, and was also consistent with the direction of the maximum principal stress. Our results obtained in this paper showed that the apparent resistivity anomaly observed near the epicenter before the mainshock could be served as seismic precursory for short-term earthquake prediction, therefore the dynamic evolution of the apparent resistivity anomaly is of great significance for understanding the mechanism of earthquake and the distribution of stress field. |
| |
| Keywords: | Jiuzhaigou earthquake Apparent resistivity Temporal-spatial distribution Variations of apparent resistivity anomaly Focal mechanism |
| 本文献已被 CNKI 等数据库收录！ |
| 点击此处可从《地球物理学报》浏览原始摘要信息 |
| 点击此处可从《地球物理学报》下载免费的PDF全文 |
|
