Gas hydrate dissociation may pose serious geohazards. The response of the seafloor to hydrate dissociation is important for geohazards, marine environments and global climate. We studied how hydrate dissociation affects underground temperature and pressure and how dissociation may lead to seafloor deformation. Here, we designed a laboratory model experiment to visualize fluid migration and seafloor deformation during hydrate dissociation at atmospheric pressure. Our experiments show visible gas pipes, migratory gas and gas pockets due to hydrate dissociation and explain the newly discovered discordance between the slide plane and the base of the gas hydrate stability zone. We found that the underlying free gas and gas conduits not only are favorable factors for forming hydrates but also can be promoted by hydrate dissociation. The temperature, pressure, and seafloor deformation are collected during the experiments. Our results show that the hydrate dissociation process is an endothermic reaction. More importantly, hydrate dissociation-induced overpressure exhibits a sudden decrease after slow growth and this inflation–deflation cycle resembles breathing. In our experiments, seafloor deformation are dominated by underground overpressure and lags up to about ten minutes. This deformation pattern could help forecast seafloor subsidence based on deformation observations. Overpressure monitoring is effective and saves time to cope with imminent geohazards. This pattern is important for geologists and engineers to forecast hydrate-related geohazards.

中文翻译：

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海底呼吸有助于预测与水合物相关的地质灾害

天然气水合物分解可能造成严重的地质灾害。海底对水合物解离的反应对于地质灾害、海洋环境和全球气候都很重要。我们研究了水合物分解如何影响地下温度和压力以及分解如何导致海底变形。在这里，我们设计了一个实验室模型实验，以可视化大气压下水合物解离过程中的流体迁移和海底​​变形。我们的实验显示了由于水合物解离而产生的可见气体管道、迁移气体和气穴，并解释了新发现的滑动面与天然气水合物稳定区底部之间的不一致。我们发现下面的游离气体和气体管道不仅是形成水合物的有利因素，而且还可以通过水合物解离来促进。在实验过程中收集温度、压力和海底变形。我们的结果表明水合物解离过程是吸热反应。更重要的是，水合物解离引起的超压在缓慢增长后突然下降，这种膨胀-紧缩循环类似于呼吸。在我们的实验中，海底变形主要由地下超压主导，并且滞后长达约十分钟。这种变形模式可以帮助根据变形观测来预测海底沉降。超压监测非常有效，可以节省应对迫在眉睫的地质灾害的时间。这种模式对于地质学家和工程师预测与水合物相关的地质灾害非常重要。