Monitoring of snow avalanches using a seismic array: Location, speed estimation, and relationships to meteorological variables
Monitoring of snow avalanches using a seismic array: Location, speed estimation, and relationships to meteorological variables
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使用地震阵列监测雪崩：位置、速度估计以及与气象变量的关系
DOI：
10.1029/2011jf002106
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发表时间：
2012
影响因子：
--
通讯作者：
A. Helmstetter
中科院分区：
文献类型：
--
作者：
P. Lacroix;J. grasso;J. Roulle;G. Giraud;D. Goetz;S. Morin;A. Helmstetter
[1]有必要对雪崩进行监测，以便更好地了解雪崩的触发机制，并最终提高预报性能。在过去的20年里，地震监测已经由几个小组开发，在探测、定位和表征雪崩方面具有巨大的潜力。2009-2010年冬季，在靠近Saint-Christophe-en-Oisans村(海拔1700米)的法国阿尔卑斯山安装了地震天线。由7个传感器组成的阵列在2009年10月和11月无雪条件下运行50天，在2010年1月和2月有雪情况下运行40天。它记录了不同类型的地震事件，包括雪崩、崩塌、枪击以及地区性和地区性微震。80个雪崩信号被肉眼识别出来。使用波束形成方法，我们能够在半径约3公里的不同方向的斜坡上定位雪崩并跟踪它们的传播。这种定位技术可以估计雪崩的锋面速度，范围在12到32m S−1之间。该方法还可以区分干雪崩和湿雪崩。由于该地区斜坡的长度，雪崩的持续时间可能长达380 S。地震监测提供了雪崩的精确时间目录，可以用来分析气象力量对雪崩触发的影响。降雪是这一时期雪崩活动的主要驱动力，相关性最强。在研究期间，我们的结果表明，降水对积雪不稳定的影响大约持续6天。
[1] Monitoring snow avalanches is necessary in order to better understand their triggering mechanisms and ultimately improve forecast performance. Seismic monitoring has been developed by several groups over the last 20 years and holds great potential to detect, locate, and characterize snow avalanches. During the 2009–2010 winter, a seismic antenna was installed in the French Alps close to the village of Saint-Christophe-en-Oisans (1700 m above sea level). The array of seven sensors operated during 50 days in October and November 2009 under snow-free conditions and during 40 days in January and February 2010 in presence of snow. It recorded different types of seismic events including snow avalanches, rockfalls, shots, and regional and local microearthquakes. Eighty avalanche signals were visually identified. Using a beam-forming method, we were able to locate snow avalanches on slopes of various orientations in a radius of about 3 km and track their propagation. The location technique allowed for the estimation of avalanches' front speed, which ranged between 12 and 32 m s−1. The method can also distinguish dry and wet snow avalanches. Durations of avalanches can be as long as 380 s because of the length of the slopes in the area. Seismic monitoring provides a catalog of avalanches with precise times, which can be used to analyze the impact of meteorological forcings on the avalanche triggering. Snowfall is found to be the dominant forcing of avalanche activity during this period, as revealed by the strongest correlation. For the period of study, our results suggest that the impact of precipitation on the snowpack instability lasts for about 6 days.