Collaborative Research: Integrated Volcano Geodesy and Seismology: Earthquakes at Silicic Domes

硅质穹顶的生长是沿大陆弧火山活动最常见的表现之一。这项研究将通过采用新的光学图像分析、传统的倾斜测量和宽带地震研究来调查大地测量和火山穹顶的宽带地震活动之间的联系。PIS最近的工作表明，圣地亚吉托穹顶的安山岩/英安岩化学的长周期地震，伴随着快速(~少数S)和剧烈(10厘米)的地表抬升，然而这种联系的大地测量学和地震学只在有限的频带内探索了极少数的喷发事件。圣地亚吉托的拟议工作将结合对穹顶活动的立体视频和时间推移观测，并结合能够对地震长周期和超长周期震源机制进行反演的地震网络几何结构。结合长达一年的倾斜仪和时间推移图像，我们将研究静态和动态穹顶运动的地震响应。在12个月内进行的调查将有助于调查短期和长期的岩浆质量流动周期、地下穹顶结构的时间趋势及其与爆炸活动的关系。地震传统上是用地震仪记录的，但也能看到发生在S地表(或附近)的某些类型的火山地震。与其他类型的地球物理仪器配合使用。在这项研究中，将使用新的光学工具，如高分辨率数码相机，来量化从几秒到几天再到几个月的时间尺度上发生的地面运动。我们的项目侧重于发生在硅质火山系统的地震，特别是危地马拉的圣地亚吉托火山，它往往会喷出粘性熔岩，也会爆炸性、间歇性地喷发，有时甚至是危险的。这种类型的火山在世界各地很常见，往往会表现出各种神秘的地震类型，需要更好地了解这些类型，才能更可靠地预测火山动乱。光学和地震观测，加上声学和传统的大地测量监测，将使我们能够了解这种类型的活火山内部和表面发生的运动。

Silicic dome growth represents one of the most common eruptive manifestations of volcanic activity along continental arcs. This study will investigate the links between geodesy and broadband seismicity at volcanic domes by employing novel optical image analyses, conventional tilt measurements, and broadband seismic studies. Recent work by the PIs has shown that long period earthquakes at Santiaguito dome, of andesitic / dacitic chemistry, are accompanied by rapid (~few s) and dramatic (10s of cm) surface uplift, however this linked geodesy and seismology has only been explored for a very few eruptive events in a limited band. Proposed work at Santiaguito will incorporate stereoscopic videographic and time lapse observations of dome activity in conjunction with a seismic network geometry that is capable of inverting for both the seismic long period and very long period source mechanisms. Coupled with year-long tiltmeter and time lapse imagery we will investigate seismic response to static and dynamic dome motions. Surveys conducted over twelve months will serve to investigate both short and long term magma mass flux cycles, temporal trends in subsurface dome structure, and their relation to explosive activity. Earthquakes are traditionally recorded with seismometers, but some types of volcanic earthquakes occurring at (or near) the Earth?s surface can also be ?seen? with other types of geophysical instrumentation. In this study, novel optical tools, such as high resolution digital cameras, will be used to quantify surface ground motion occurring at a range of time scales ranging from seconds to days to months. Our project focuses on earthquakes that occur at silicic volcanic systems, and in particular at Santiaguito Volcano in Guatemala, which tend to effuse viscous lava and also erupt explosively and intermittently and sometimes hazardously. This type of volcano is common worldwide and tends to exhibit a wide range of enigmatic earthquake types that need to be better understood to more reliably predict volcanic unrest. Optical and seismic observations, coupled with acoustic and traditional geodetic monitoring, will enable us to understand the movements that occur within and at the surface of this type of active volcano.