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2008年5月1日至7月4日汶川8.0级地震前后,对距震中约400 km的重庆北温泉7个泉点进行采样监测,发现其水温、水量及水化学特征均发生了较大变化:(1)所有泉点震后水温都下降了1℃左右;(2)海拔相对较高的BWQ-2、BWQ-3、BWQ-4泉点相继断流,而下游海拔较低的BWQ-1泉点水量则增加了15 L/s,BWQ-6泉点水量也有所增加;(3)海拔较低泉点泉水中K+、Na+、Ca2+浓度减少,Mg2+浓度增大,且K+、Na+、Ca2+浓度呈正相关;Fe3+、Mn2+浓度于地震当日成倍增长,随后逐渐减小,7月4日时浓度与5月1日相当;SO42-、F-浓度增大后逐渐减少。引起北温泉水物理化学变化的主因是:由于汶川强烈地震,导致北温泉区上覆盖层裂隙与下伏温泉含水层裂隙贯通,地表或上覆盖层低温水汇入含水层所致。
Before and after the Wenchuan M8.0 Earthquake from May 1 to July 4, 2008, sampling and monitoring were conducted on seven spring points of Chongqing North Hot Spring about 400 km away from the epicenter, and its water temperature, water amount and water chemistry characteristics were greatly changed : (1) The water temperature of all the springs dropped by about 1 ℃ after the earthquake; (2) the BWQ-2, BWQ-3 and BWQ-4 springs at relatively high altitude successively cut off, while the downstream lower BWQ- (3) The concentrations of K +, Na + and Ca2 + in spring water of lower spring point decreased and the concentration of Mg2 + increased, and the contents of K +, Na +, K2O, The concentration of Fe3 + and Mn2 + increased exponentially on the day of the earthquake, and then decreased gradually. The concentration of Fe3 + and Mn2 + on July 4 was comparable to that on May 1; the concentration of SO42- and F- decreased gradually after the increase. The main causes of physical and chemical changes of North Hot Spring are: due to the strong Wenchuan earthquake, resulting in the northern hot springs overlying fissures and underlying hot springs aquifers fissures through the surface or overlying cover of low temperature water into the aquifer caused.