Relative seismic velocity variations correlate with deformation at Kīlauea volcano.
Relative seismic velocity variations correlate with deformation at Kīlauea volcano.
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DOI：
10.1126/sciadv.1700219
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发表时间：
2017-06
期刊：
影响因子：
13.6
通讯作者：
White RS
中科院分区：
文献类型：
--
作者：
Donaldson C;Caudron C;Green RG;Thelen WA;White RS
地震速度的变化与变形在Kendlauea火山，先进的噪声干涉测量作为一种监测工具。地震噪声干涉测量法允许连续和实时测量通过火山建筑物的相对地震速度。由于地震速度对系统的加压状态很敏感，这种方法是一种令人兴奋的活火山监测新工具。尽管这一工具的潜力，还没有研究全面比较速度与其他地球物理观测的短期时间尺度上的火山在一个显着的时间长度。我们使用火山震颤（~0.3至1.0 Hz）在Kendlauea作为一个被动源的干涉测量相对速度随时间的变化。通过对230个台站对之间一天的地震记录的垂直分量进行互相关，我们提取了时间滞后长达120 s的相干和时间一致的尾波信号。我们得到的相对速度的时间序列显示了相对速度和在Kamplauea峰会测量的径向倾斜记录之间的显着相关性，几乎在整个研究期间（2011年6月至2015年11月），在几天到几周的时间尺度上始终相关。当顶点在收缩-膨胀事件中不断变形时，速度分别减小和增大。在Kendlauea的应变模型表明，在膨胀的浅岩浆水库（1至2公里以下的表面），大部分的建筑物是由压缩，因此关闭裂缝，并产生更快的速度，反之亦然。在这项研究中，相对速度和变形之间的良好相关性提供了一个机会，更好地了解在火山引起地震速度变化的机制，从而实现被动干涉测量作为监测工具的潜力。
Seismic velocity changes correlate with deformation at Kīlauea volcano, advancing noise interferometry as a monitoring tool. Seismic noise interferometry allows the continuous and real-time measurement of relative seismic velocity through a volcanic edifice. Because seismic velocity is sensitive to the pressurization state of the system, this method is an exciting new monitoring tool at active volcanoes. Despite the potential of this tool, no studies have yet comprehensively compared velocity to other geophysical observables on a short-term time scale at a volcano over a significant length of time. We use volcanic tremor (~0.3 to 1.0 Hz) at Kīlauea as a passive source for interferometry to measure relative velocity changes with time. By cross-correlating the vertical component of day-long seismic records between ~230 station pairs, we extract coherent and temporally consistent coda wave signals with time lags of up to 120 s. Our resulting time series of relative velocity shows a remarkable correlation between relative velocity and the radial tilt record measured at Kīlauea summit, consistently correlating on a time scale of days to weeks for almost the entire study period (June 2011 to November 2015). As the summit continually deforms in deflation-inflation events, the velocity decreases and increases, respectively. Modeling of strain at Kīlauea suggests that, during inflation of the shallow magma reservoir (1 to 2 km below the surface), most of the edifice is dominated by compression—hence closing cracks and producing faster velocities—and vice versa. The excellent correlation between relative velocity and deformation in this study provides an opportunity to understand better the mechanisms causing seismic velocity changes at volcanoes, and therefore realize the potential of passive interferometry as a monitoring tool.