Monitoring of the volcanic fluid system and elucidation of the deep-magma ascent mechanism at Aso volcano

为了监测火山流体系统，阐明岩浆喷发前上升的机制，我们在阿苏火山部署了宽带地震仪和GPS网络。我们还进行了一系列密集阵列观测，以监测浅层流体流动活动。结果：(1)我们成功地观察到火山浅部极快的流体运动，这似乎表明了一个发育良好的浅导管系统；(2)我们提出了一个模型，解释了由于热液流体流动的单一导管系统的活动而引起的长周期（15秒）和短周期（15秒）地震活动。我们还开发了一种有效的方法来计算充满流体的裂缝的动力响应，这种方法对火山地震学中可能遇到的许多应用都是灵活的。

In order to monitor the volcanic fluid system and to elucidate the mechanism of magma ascent before eruptions, we deployed broadband seismometer and GPS networks in Aso volcano. We also conducted a series of dense array observations to monitor shallow fluid flow activities. As the result, (l) we were successful to observe extremely fast fluid movements in the shallow part of the volcano that appear to indicate a well developed shallow conduit system, (2) we have presented a model that explains the activities of long-period (15s) and short-period (1s) tremors as a result of the activities of a single conduit system of hydrothermal fluid flows. We have also developed an efficient method to compute the dynamic response of a fluid-filled crack that is flexible to many applications which may be encountered in volcano seismology.