Hot spring discharge was linked to the 2011 Mw 6.6 Iwaki earthquake. Periodic surveys revealed that the discharge continued for more than 7 years, which is a rare and valuable long-term record of hot spring discharge triggered by an earthquake in a non-volcanic area. In terms of coseismic changes, based on a comparison of the spatial distribution of changes in the coseismic water head and calculated crustal volumetric strain using a fault model, hot spring water discharge was found to be caused by a change in the coseismic crustal volumetric strain. As for the postseismic changes, observations over 7 years revealed a gradual rise in the temperature and chloride ion concentration of the hot spring water. Such long-term hot spring discharge may be explained by the following two causes: the rise of thermal water from the deep part and the permeability changes along the hot spring channels.

中文翻译：

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2011 年日本磐城 6.6 级地震后的深层地下水排放

温泉排放与 2011 年 Mw 6.6 磐城地震有关。定期勘察显示，此次泄洪持续了7年多，是非火山区地震引发的温泉泄洪的罕见且有价值的长期记录。在同震变化方面，通过比较同震水头变化的空间分布与断层模型计算的地壳体积应变，发现温泉排水是由同震地壳体积应变变化引起的。至于震后变化，7年多的观测表明，温泉水的温度和氯离子浓度逐渐升高。这种长期的温泉排放可能由以下两个原因来解释：