Seismo-Acoustic Dynamics of Silicic Dome Eruptions

研究人员建议研究安第斯山脉的两座火山，瓜瓜皮钦查火山和厄瓜多尔的通古拉瓦火山，因为它们表现出相对频繁的爆炸事件（火山碎屑和火山岩浆），为实地研究提供了无与伦比的机会。皮钦查火山的活动类似于Unzen、Merapi、Bezmianny和Monserrat火山的活火山活动。通古拉瓦非常危险，因为它陡峭的海拔和对巴诺斯市构成的危险。该项目的目的是对一般的硅火山作用，特别是这两座火山进行实地观测和发展新的模式。为了了解硅质圆顶火山脱气的控制特征，将安装新型仪器，包括宽带地震和次声传感器，以监测斯特隆波利亚型爆炸活动。完成高保真观测所需的技术，包括硬件和软件，将转让给基多地理研究所的厄瓜多尔同事。利用次声传声器阵列和宽带地震仪记录的弹性和声能量辐射，评估爆炸能量释放、相对能量分配到地面和大气以及爆炸源位置。数字化视频记录将用于校准次声产生与气体羽流喷射速度，并验证源的时间、起源和位置。将开发圆顶爆炸脱气的物理模型，并将其与低粘度、开放的岩浆系统（Stromboli、Karymsky、Arenal、Erebus）进行比较，以便次声波和地震工具可以用于远程预测所有类型火山爆炸的脱气行为。该提案的主要影响将是：1)开发新的火山爆发模型，应用于以前未被探索的火山活动；2)对厄瓜多尔危险火山的地震/声学信号进行新的观测；3)在厄瓜多尔和美国研究人员之间建立强有力的合作，减少活火山的危害；4)在危险火山发生大型崩塌事件之前对危害进行评估。本项目由国际科学与工程办公室美洲项目共同赞助。

The investigators propose a study of two Andean volcanoes, Guagua Pichincha and Tungurahua, Ecuador, because they exhibit relatively frequent explosive events (both pyroclastic and phreato-magmatic) and offer unparalleled access for field study. Activity at Pichincha is an analogue for active volcanism at: Unzen, Merapi, Bezmianny, and Monserrat. Tungurahua is extremely hazardous due to its steep elevation and danger posed to the city of Banos. The project is aimed at field observations and developing new models for silicic volcanism in general and these two volcanoes specifically.To understand the controlling features of volcanic degassing at silicic domes new instrumentation, including broadband seismic and infrasonic acoustic sensors will be installed to monitor the Strombolian-type explosion activity. The technology required to accomplish high fidelity observations, including hardware and software, will be transferred to Ecuadorian Colleagues at the Instituto Geofisica in Quito. Elastic and acoustic energy radiation recorded with arrays of infrasonic microphones and broad-band seismometers will be used to assess the explosive energy release, relative energy partitioning into the ground and atmosphere, and explosion source location. Digitized video records will be used to calibrate infrasound generation with gas plume ejection velocities and verify source time origin and locations. Physical models of explosive degassing at domes will be developed and compared to lower-viscosity, open-vent magmatic systems (Stromboli, Karymsky, Arenal, Erebus), so that infrasonic and seismic tools can be used to remotely predict degassing behavior for all types of volcanic explosions. The major impact of this proposal will be 1) the development of new volcano explosion models applied to previously unexplored volcanic activity, 2) new observations of seismo/acoustic signals at hazardous volcanoes in Ecuador, and 3) establishment of a strong collaboration between Ecuadorian and U.S. researchers on active volcanic hazard reduction, 4) assessment of hazard prior to large collapse events on dangerous volcanoes.This project is co-sponsored by the Americas Program in the Office Of International Science And Engineering.