RAPID: Hydrological responses to the August, 2014, Napa earthquake

地震会产生水文反应，如水流增加和水井水位变化。这种水文反应很重要，因为它们提供了在空间和时间尺度上对水文和构造过程耦合的独特洞察，否则很难研究这些过程。2014年8月纳帕6级地震导致几条以前干燥的溪流开始流动，在严重干旱的时期，这是一个意想不到的水源。对地震引起的水文变化的研究对水资源和工程有影响，包括评估地震在破坏含水层、影响地下水库和改变供水方面的作用。对地震的水文响应的起源一直是争议的主题，这在很大程度上是因为有许多模型来解释观测结果，而适合于区分假说的测量方法很少。纳帕地震提供了一个检验假设的独特机会，因为水出现在干燥或接近干燥的溪流中，因此没有被已经在地表流动的水稀释。PI将在一年内收集水样并进行流量测量，以回答以下问题：a)溪流中的过量流量是来自浅层还是深层？B)地下表面的性质是否有永久性变化，如渗透性？C)对于解释观察到的变化，静态应力还是动态应力更重要？

Earthquakes generate hydrological responses, such as increases in stream flow and changes in the water level in wells. Such hydrologic responses are important because they provide unique insight into the coupling of hydrologic and tectonic processes at spatial and temporal scales that are otherwise difficult to study. The August 2014 magnitude 6 Napa earthquake caused several previously dry stream to begin flowing, an unexpected source of water during a time of intense drought. The study of earthquake-induced hydrologic changes has implications for water resources and engineering, including assessing the role of earthquakes in damaging aquifers, affecting underground repositories, and changing water supplies. The origin of hydrologic responses to earthquakes has been the subject of controversy, in large part because there are many models to explain observations and few measurements suitable for distinguishing between hypotheses. The Napa earthquake provides a unique opportunity to test hypotheses because water emerged in dry or nearly dry streams and hence was not diluted by water already flowing at the surface. The PI will collect water samples and make discharge measurements over a 1-year period in order to answer the following questions: a) Does the excess discharge in streams originate from the shallow or deep subsurface? b) Are there permanent changes in properties of the subsurface such as permeability? c) Are static or dynamic stresses more important for explaining the observed changes?