Calibrating the Liquefaction Severity Number (LSN) for Varying Misprediction Economies: A Case Study in Christchurch, New Zealand
Calibrating the Liquefaction Severity Number (LSN) for Varying Misprediction Economies: A Case Study in Christchurch, New Zealand
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校准不同预测错误经济体的液化严重度数 (LSN)：新西兰基督城的案例研究
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发表时间：
2015
期刊：
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通讯作者：
B. Bradley
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文献类型：
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作者：
B. Maurer;R. Green;M. Cubrinovski;B. Bradley
决策阈值是使用液化危害框架的核心，如液化严重性编号（LSN）。然而，通常没有意识到的是，所提出的阈值固有地关联到：（1）用于在危险框架内计算FSliq的程序;（2）评估的数据集;以及（3）如本文所示，用于选择阈值的方法，以及隐含于此类选择的假设的误预测经济。这项研究提出了一种标准化的方法，通过这种方法，经济（即，错误预测的后果）被用来做出关于危险评估的逻辑决策。通过对坎特伯雷地震的7,000个液化案例研究的分析，提出了不同误预测经济的最佳LSN决策阈值。这些阈值在很大程度上取决于基本的经济假设，当假阳性和假阴性具有相似的成本时，LSN = 15.4是最佳的。假设的预测错误的经济，隐含在文献中提出的所有阈值危险值，因此可能有重大影响的液化危险的前瞻性评估。
Decision thresholds are central to the use of liquefaction hazard frameworks such as the liquefaction severity number (LSN). However, it is often unappreciated that proposed thresholds are inherently linked to: (1) the procedure used to compute FSliq within the hazard framework; (2) the assessed dataset; and (3) as demonstrated herein, the approach used to select thresholds, and the assumed misprediction economies implicit to such selections. This study proposes a standardized approach by which the economies (i.e., consequences) of misprediction are used to make logical decisions with respect to hazard assessment. Optimum LSN decision thresholds are proposed for varying misprediction economies via an analysis of 7,000 liquefaction case studies from the Canterbury earthquakes. These thresholds strongly depend on underlying economic assumptions, with LSN = 15.4 being optimal when false positives and false negatives have similar costs. Assumed misprediction economies, implicit to all threshold hazard values proposed in the literature, could thus have significant implications for forward assessments of liquefaction hazard.