Calibration and validation of rainfall thresholds for shallow landslide forecasting in Sicily, southern Italy
Calibration and validation of rainfall thresholds for shallow landslide forecasting in Sicily, southern Italy
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DOI：
10.1016/j.geomorph.2014.10.019
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发表时间：
2015-01-01
期刊：
影响因子：
3.9
通讯作者：
Guzzetti, F.
中科院分区：
文献类型：
--
作者：
Gariano, S. L.;Brunetti, M. T.;Guzzetti, F.
经验降雨量阈值是预测降雨引起的浅层滑坡可能发生的工具。对滑坡发生的准确预测需要可靠的阈值，在将其用于业务预警系统之前，需要对其进行适当的验证。我们利用2002-2011年间在意大利南部西西里岛造成至少223次浅层滑坡的200种降雨条件目录，来确定发生浅层滑坡的区域事件持续时间-累积事件降雨量(ED)阈值。我们计算了不同超越概率水平的ED阈值，并使用合并的Bootstrap非参数技术确定了与阈值相关的不确定性。我们进一步确定了次区域阈值，并研究了岩性和季节性在西西里岛浅层滑坡发生中的作用。接下来，我们使用29种降雨条件验证了区域降雨阈值，这些降雨条件在2012年导致了西西里岛42个浅层山体滑坡。我们基于联想表、技能得分和不同超越概率水平(从1%到50%)下阈值的接收器操作特征(ROC)分析来进行验证。由于缺乏关于滑坡发生的信息，对降雨量阈值的确认受到阻碍。因此，我们考虑了由于缺乏信息而导致的意外情况和技能分数变化的影响。基于获得的结果，我们提出了一种用于客观识别阈值的通用方法，该方法在最大化正确预测和最小化错误预测(包括漏报和误报)之间提供最佳平衡。我们预计，该方法将提高降雨量阈值的可靠性，促进在区域浅层滑坡预报的业务预警系统中使用有效的降雨量阈值。(C)2014爱思唯尔B.V.保留所有权利。
Empirical rainfall thresholds are tools to forecast the possible occurrence of rainfall-induced shallow landslides. Accurate prediction of landslide occurrence requires reliable thresholds, which need to be properly validated before their use in operational warning systems. We exploited a catalogue of 200 rainfall conditions that have resulted in at least 223 shallow landslides in Sicily, southern Italy, in the 11-year period 2002-2011, to determine regional event duration-cumulated event rainfall (ED) thresholds for shallow landslide occurrence. We computed ED thresholds for different exceedance probability levels and determined the uncertainty associated to the thresholds using a consolidated bootstrap nonparametric technique. We further determined subregional thresholds, and we studied the role of lithology and seasonal periods in the initiation of shallow landslides in Sicily. Next, we validated the regional rainfall thresholds using 29 rainfall conditions that have resulted in 42 shallow landslides in Sicily in 2012. We based the validation on contingency tables, skill scores, and a receiver operating characteristic (ROC) analysis for thresholds at different exceedance probability levels, from 1% to 50%. Validation of rainfall thresholds is hampered by lack of information on landslide occurrence. Therefore, we considered the effects of variations in the contingencies and the skill scores caused by lack of information. Based on the results obtained, we propose a general methodology for the objective identification of a threshold that provides an optimal balance between maximization of correct predictions and minimization of incorrect predictions, including missed and false alarms. We expect that the methodology will increase the reliability of rainfall thresholds, fostering the operational use of validated rainfall thresholds in operational early warning system for regional shallow landslide forecasting. (C) 2014 Elsevier B.V. All rights reserved.