A New Method for the Estimation of Avalanche Distance Exceeded Probabilities
A New Method for the Estimation of Avalanche Distance Exceeded Probabilities
复制标题
雪崩距离超出概率估计的新方法
DOI：
10.1023/b:geop.0000006084.45248.22
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发表时间：
2003
影响因子：
4.6
通讯作者：
F. Savi
中科院分区：
文献类型：
--
作者：
M. Barbolini;F. Cappabianca;F. Savi
在任何雪崩危险评估方法中，一个关键点是评估雪崩距离超过概率，即，雪崩到达或超过给定路径沿着任何指定位置的年概率。通常情况下，这个问题所面临的估计雪量的起始区，可能会积累一个平均每T年的降雪记录的统计分析，然后使用这个体积作为输入到一个适当的校准雪崩动力学模型，以确定这个设计事件的runout distances。该方法确定了在重现期（即某事件重复发生的平均时间间隔）<$T的考虑值内可能受到雪崩影响的区域。然而，它不允许我们评估在跳动区中任何给定点的实际雪崩遭遇概率。在目前的工作中，这个概率是通过数值积分的表达式P（x）= 0∞ P*（V）f（V）dV计算的，其中f是雪崩释放体积V的概率密度函数（PDF），P* 是雪崩到达或通过点x的概率，如果释放体积是V;后一个概率是通过雪崩动力学模拟计算的。该程序是使用一个一维的液压连续雪崩动态模型，校准数据从不同的意大利阿尔卑斯山脉范围内，并施加到一个真实的世界的危险映射问题。
A crucial point in any methodology for avalanche hazard assessment is the evaluation of avalanche distance exceeded probability, i.e., the annual probability that any assigned location along a given path is reached or exceeded by an avalanche. Typically this problem is faced by estimating the snow volume in the starting zone that is likely to accumulate an average every T years by statistical analysis of snowfall record, and then using this volume as input to an appropriately calibrated avalanche dynamics model to determine the runout distancesfor this design event. This methodology identifies the areas that canbe affected by an avalanche for the considered value of the return period (i.e. the average interval of time for a certain event to repeat itself), ¯T. However, it does not allow us to evaluate the actual avalanche encounter probability for any given point in the runout zone. In the present work this probability is computed by numerical integration of the expression P(x) = ∫0∞ P*(V)f(V) dV, where f is the probabilitydensity function (PDF) of the avalanche release volume V, and P* is the probability of the point x being reached or passed by an avalanche if the release volume is V; this latter probability is calculated by avalanche dynamics simulations. The procedure is implemented using a one-dimensional hydraulic-continuum avalanche dynamic model, calibrated on data from different Italian Alpine ranges, and is applied to a real world hazard mapping problem.