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

合作研究：综合火山大地测量学和地震学：硅质穹顶的地震

• 批准号: 0838395
• 负责人: Jonathan Lees
• 金额: $ 13.07万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-15 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0838395&HistoricalAwards=false
• 关键词: Collaborative; Research; Integrated; Volcano; Geodesy

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.

硅质穹隆生长是沿着大陆弧火山活动最常见的喷发表现之一。本研究将通过采用新的光学图像分析、常规倾斜测量和宽带地震研究，调查大地测量和火山圆顶宽带地震活动之间的联系。PI最近的工作表明，安山质/英安岩化学性质的Santiaguito圆顶发生的长期地震伴随着快速（~几秒）和剧烈（10秒）的表面隆起，然而，这种相关的大地测量学和地震学仅在有限范围内探索了极少数喷发事件。拟议的工作将纳入立体摄像和时间推移观测圆顶活动与地震网络几何结构，能够反演地震长周期和非常长的周期源机制。结合长达一年的倾斜仪和时间推移图像，我们将研究地震对静态和动态圆顶运动的反应。在12个月内进行的调查将用于调查短期和长期岩浆质量通量周期、地下穹隆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，但某些类型的火山地震发生在地球上（或附近）？的表面也可以是？看见了吗？与其他类型的地球物理仪器。在这项研究中，新的光学工具，如高分辨率数码相机，将被用来量化地表地面运动发生在一个范围内的时间尺度，从秒到天到月。我们的项目侧重于发生在火山系统的地震，特别是在危地马拉的卡萨基托火山，它往往喷出粘性熔岩，也爆发和间歇性，有时是危险的。这种类型的火山在世界范围内很常见，往往会出现各种各样的神秘地震类型，需要更好地了解这些类型，以便更可靠地预测火山动荡。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活火山内部和表面发生的运动。