Abstract: Mud volcano is a conical sedimentary body formed by high-pressure mud and gas-dominated fluid migrated to the surface through faults and other channels deep underground, which looks like a volcanic cone formed by magma-volcanism. As a product of crustal movement, mud volcano can bring a large amount of valuable information from deep to the surface when erupting. Therefore, mud volcano is called "god-given borehole" with a depth of 7~12km. Mud volcanoes are the result of upthrust of trapped gases released by the pressure in the stratum and also the channel for the upward migration of gases in the earth. The submarine mud volcano is one of the signs of hydrate and the living evidence of hydrate. The Wusu mud volcanoes are located in the northern Tianshan tectonic belt. Since the mud volcamoes locate in the active part of the tectonic belt and are well connected to the underground, their active degree has a good correlation with the seismicity. The earthquake cases studies based on the 7a long real-time macroscopic monitoring data and the more than 3a long geochemical monitoring data of the Wusu mud volcanoes show that in the earthquake cases of M_S ≥ 5.0 within the range of 300km around the Wusu mud volcanoes, the abnormal mud gushing quantity obviously increased by macroscopic monitoring before 9 out of 13 earthquakes. The geochemical microcosmic monitoring data showed obvious abnormal changes before 3 out of 6 earthquakes. The anomalous duration from the emergence of the anomaly to the occurrence of the earthquake is mainly of the mid-term(6~12 months). Before the Jinghe M_S6.6 earthquake on August 9, 2017, the Wusu mud volcanoes spewed violently and the chemical components showed an obvious high value anomaly. In January 2017, there was a significant increase in the amount of mud spewing in Aiqigou No.1mud volcano and Baiyanggou No.1mud volcano, and one month before the earthquake, there was the phenomenon that mud gushing amount of Aiqigou No.2 mud volcano gradually increased and the volcano was from dormant to active. There were obvious high values appearing before the earthquake in F^-and SO₄^2- in the Aiqigou No.1mud volcano and in F^-, CO₃^2-, SO₄^2-, Rn(gas), CH₄, Ar and N₂ in Baiyanggou(No.1 and 2)mud volcanoes. The values of F^-, CO₃^2-, SO₄^2-, Ar and N₂ showed short-term anomalies, while CH₄ and Rn(gas)showed medium term anomalies. Giggenbach triangular diagram (Na-K-Mg) indicates that the water-rock reaction of Baiyanggou mud volcanoes is complete and little disturbed by the outside. The water-rock reaction of the Aiqigou mud volcanoes is still ongoing, which can explain why the precursor anomaly of the chemical components of the Baiyanggou mud volcanoes is more obvious than that of the Aiqigou mud volcanoes. The geothermal reservoir temperature of the study area is estimated by using a cationic (Na-K, K-Mg, Na-K-Ca) geothermometer. The geothermal reservoir temperature of the Wusu mud volcanoes is about 70℃, and the circulation depth is about 3km. In the process of earthquake preparation, the mud carries deep chemical components to the ground surface due to the effect of compression stress(the result of focal mechanism)or the concentration of regional tectonic stress with earthquake preparation; Or the rock strata in or near the seismogenic area are deformed, the depth of liquid circulation will increase, and the water-rock reaction will be accelerated, which will increase the concentration of some ionic components, and the squeezing process will cause a large number of mud to gush out of the ground, carrying geochemical components. Therefore, the gushing quantity and some chemical components of the mud volcanoes were obviously abnormal before the earthquake.

Key words: Jinghe M_S6.6 earthquake, Wusu mud volcanoes, response feature, chemical component

摘要： 乌苏泥火山群位于北天山构造带，由于其处于构造活跃部位，且与地下的连通性较好，其活跃程度与地震活动存在明显的相关性。通过分析乌苏泥火山群历时超过7a的实时宏观监测资料和超过3a的地球化学监测资料，认为在距乌苏泥火山群300km范围内M_S5.0及以上的地震震例中，2011年8月以来的13次地震中有9次地震前泥火山喷涌量的宏观监测数据出现明显的增大异常；2015年7月以来的6次地震中有3次地震前泥火山的地球化学微观监测数据出现明显的异常变化；异常出现的时间点至发震的间隔以中期（6~12个月）为主。2017年8月9日精河M_S6.6地震前，乌苏泥火山群剧烈喷涌，化学组分呈明显的高值异常。艾其沟1号和白杨沟1号泥火山在2017年1月的喷涌量显著增大，艾其沟2号泥火山在震前1个月出现由休眠到活跃、泥浆喷涌量逐渐增大的现象。艾其沟1号泥火山的F^-、SO₄^2-，白杨沟（1号及2号）泥火山的F^-、CO₃^2-、SO₄^2-、Rn（气）、CH₄、Ar和N₂在震前均出现明显的高值变化；F^-、CO₃^2-、SO₄^2-、Ar和N₂表现为短期异常，CH₄、Rn（气）表现为中期异常。Giggenbach三角图（Na-K-Mg）显示：白杨沟泥火山的水-岩反应较弱，受外界干扰小；艾其沟泥火山水-岩反应仍在进行，且受到了一定的外界干扰，因此白杨沟泥火山化学组分的地震前兆异常比艾其沟泥火山更明显。利用阳离子（Na-K、K-Mg和Na-K-Ca）地温计估算研究区的热储温度，得到乌苏泥火山群的热储温度约70℃，循环深度约3km。在地震孕育的过程中，受挤压应力（由震源机制判断）作用的影响或地震孕育伴随的区域构造应力集中，导致泥浆携带深部化学组分喷发至地表；孕震区或附近的岩层发生形变，液体循环深度增加，同时加快水-岩反应的速率，使得部分离子组分的浓度增加，挤压作用使大量泥浆携带地球化学组分喷发至地表。因此，在地震前泥火山的喷涌量和部分化学组分表现出明显的异常。

关键词: 精河M_S6.6地震, 乌苏泥火山群, 响应特征, 化学组分