2012年6月30日新源Ms6.6地震前后北天山泥火山及温泉的水化学变化

2012年6月30日新源-和静M_s6.6地震前后,新疆北天山地区的泥火山及温泉出现了明显的水化学异常。在地震前后4天内,采集了两批泥火山和温泉水样品,测定了泥火山和温泉水样的水化学参数。资料表明,泥火山喷溢水属于低温、弱碱性咸水或盐水,水化类型为CI-Na,来源于储存在封闭构造中并与干旱海相、河湖相沉围岩发生了漫长而复杂水岩作用的大气降水。温泉水为中温、弱碱性SO₄·CI-Na型淡水,形成于地表水沿断裂深循环过程中的水岩作用。安集海泥火山出现同震喷溢,震后泥水温度(T)、总矿化度(TDS)、K+、Na+及Ca2+大幅上升;独山子、白杨沟及AM02泥火山为震前喷溢,独山子、白杨沟泥火山表现为T.TDS、EC、Na+、CI的升高和K⁺、Ca²⁺、Mg²⁺的降低;AM02泥火山K⁺、Mg⁺明显降低,Ca²⁺上升达223%。震后沙湾25号泉T降低7℃, TDS、电导率(EC)、K⁺、Na⁺、 Ca²⁺、 .Mg²⁺、CI^-及$SO_{4}^{2-}$升高。研究结果可用于北天山地区的地震趋势分析和改进利用各泥火山、温泉进行北天山地区地震活动性监测的水化学方法。

Hydrogeochemical Changes of Mud V olcanoes and Springs in North Tianshan Related to the June 30,2012 Xinyuan Ms6.6 Earthquake

Hydrogeochemical anomalies of mud volcanoes and springs in the North Tians-han were found before and after the June 30,2012 Xinyuan-Hejing M_s6.6 earthquake in Xinjiang Uyger autonomous region, China. Water samples from the hot springs and mud volcanoes were collected 4-days before and after the earthquake, and hydrogeochemical par rameters were measured. The data indicate that water from mud volcanoes are brine with weak alkaline and low temperatures, whose chemical type is CI-Na and may originate from the meteoric water stored in the closed structures and react with the surrounding rock complex. Water from springs is fresh with weak alkaline and medium temperatures, whose chemical type is SO4·Cl-Na, probably owing to the deep circulation of the ground-water along the faults. The Anjihai mud volcano showed coseismic anomaly, with temper ature (T), total dissolved solids (TDS),K⁺,Na⁺ and Ca²⁺ increasing greatly after the . earthquake. Mud volcanoes in Dushanzi, Baiyanggou and Aiqigou showed pre-seismic a-nomaly, with the T, TDS, conductivity(EC),Na⁺ and CI^-increasing, and K⁺,Ca²⁺ and Mg²⁺ decreasing before the earthquake in Dushanzi and Baiyanggou mud volcanoes. In Aiqigou mud volcano, there were significantly decreases in K⁺ and Mg²⁺,but Ca²⁺ in-creased by 223%. For the Shawan No. 25 spring, there were significantly decreases in TDS, EC, K⁺,Na⁺,Ca²⁺,Mg²⁺, CI^-and $SO_{4}^{2-}$ but the temperature decreased by 7℃. These results may help earthqua ke tendency analysis and improvement of hydrogeochemi-cal monitoring methods.