Average landslide erosion rate at the watershed scale in southern Taiwan estimated from magnitude and frequency of rainfall
Average landslide erosion rate at the watershed scale in southern Taiwan estimated from magnitude and frequency of rainfall
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DOI：
10.1016/j.geomorph.2014.07.022
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发表时间：
2015-01-01
期刊：
影响因子：
3.9
通讯作者：
Chiang, Shou-hao
中科院分区：
文献类型：
--
作者：
Chen, Yi-chin;Chang, Kang-tsung;Chiang, Shou-hao
本研究计算了台湾南部高平河流域的长期平均滑坡侵蚀率，并研究了极端降雨事件对滑坡侵蚀的相对重要性。该方法遵循三个步骤：首先，根据多时间、基于事件的滑坡清单计算 10 次降雨事件的滑坡体积；其次，通过水文频率分析来估算滑坡降雨的频率；第三，结合两组数据来估计平均滑坡侵蚀率。研究结果表明，平均滑坡侵蚀率为2.65-5.17 mm yr(-1)，与使用其他方法进行的其他研究报告的速率相当一致。研究还发现，极端强降雨事件对滑坡侵蚀的影响比频繁-中度降雨事件更为重要。极端降雨（最大 24 小时降雨量 >600 毫米）占平均滑坡侵蚀率的 64-79%。此外，滑坡侵蚀强度的自然变化非常大，可能会导致根据滑坡总体积估算滑坡侵蚀率存在很大的不确定性。这项研究根据涉及假设的 100 年滑坡清单的模拟结果发现了 1.2 mm yr(-1) 的不确定性。总之，本研究证明了极端降雨事件对滑坡侵蚀的重要性，并且本研究提出的方法能够在滑坡记录不足的地区计算出平均滑坡侵蚀率的可靠估计。 (C) 2014 Elsevier B.V. 保留所有权利。
This study calculated the long-term average landslide erosion rate in the Kaoping River watershed in southern Taiwan and investigated the relative importance of extreme rainfall events on landslide erosion. The method followed three steps: first, calculating landslide volumes for 10 rainfall events from a multi-temporal, event-based landslide inventory; second, estimating the frequency of landslide-generating rainfall by using hydrologic frequency analyses; and third, combining the two sets of data to estimate the average landslide erosion rate. Results of the study showed that the average landslide erosion rate is 2.65-5.17 mm yr(-1), corresponding well to rates reported in other studies using other methods. The study also found that extremeintensive rainfall events play a more important role on landslide erosion than frequent-moderate rainfall events. Extreme rainfall (maximum 24-h rainfall >600 mm) contributes 64-79% of the average landslide erosion rate. Moreover, the natural variation of landslide erosion magnitudes is extremely large and can cause significant uncertainty in estimating the landslide erosion rate from total landslide volume. This study found 1.2 mm yr(-1) of uncertainty based on simulation results involving a hypothetical 100-year landslide inventory. In summary, this study demonstrates the importance of extreme rainfall events on landslide erosion, and the method proposed in this study is capable of calculating a reliable estimate of average landslide erosion rate in areas with insufficient landslide records. (C) 2014 Elsevier B.V. All rights reserved.