The role of geomorphology, rainfall and soil moisture in the occurrence of landslides triggered by 2018 Typhoon Mangkhut in the Philippines
The role of geomorphology, rainfall and soil moisture in the occurrence of landslides triggered by 2018 Typhoon Mangkhut in the Philippines
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DOI：
10.5194/nhess-2020-259
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发表时间：
2020-08
影响因子：
4.6
通讯作者：
C. Abancó;G. Bennett;A. Matthews;M. Matera;F. J. Tan
中科院分区：
文献类型：
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作者：
C. Abancó;G. Bennett;A. Matthews;M. Matera;F. J. Tan
抽象。2018年，台风Mangkhut（当地称为台风Ompong）在菲律宾的Itogon地区引发了数千次山体滑坡。首次编制了受影响地区的滑坡清单，其中包括570平方公里区域内的1101处滑坡。该清单被用来研究更容易发生滑坡的地貌特征和土地覆盖，以及导致大面积滑坡的水文气象条件。结果表明，滑坡多发生在粘土质浅层地质的草坡和林坡上，以东南偏东向为主。与台风“山竹”相关的降雨（全球降水测量综合多卫星检索，IMERG GPM）与2018年未引发区域滑坡事件的33次高强度降雨事件进行了比较。结果表明，滑坡发生在高强度降雨，符合最高的土壤水分值（估计粘土饱和点），根据土壤水分主动被动4级（SMAP-L4）数据。我们的研究结果表明，SMAP-L4和GPM IMERG数据的滑坡灾害评估和早期预警的地面数据是稀缺的潜力。然而，在台风山竹之前的几个月里，其他降雨事件具有类似或更高的降雨强度，并且在土壤饱和时发生，并没有引发大范围的滑坡，这突出表明需要进一步研究引发台风滑坡的条件。
Abstract. In 2018 Typhoon Mangkhut (locally known as Typhoon Ompong) triggered thousands of landslides in the Itogon region of the Philippines. A landslide inventory of the affected region is compiled for the first time, comprising 1101 landslides over a 570 km2 area. The inventory is used to study the geomorphological characteristics and land cover more prone to landsliding as well as the hydrometeorological conditions that led to widespread failure. The results showed that landslides mostly occurred on grassland and wooded slopes of clay superficial geology, predominantly facing east-southeast. Rainfall (Integrated Multi-satellitE Retrievals for Global Precipitation Measurement, IMERG GPM) associated with Typhoon Mangkhut is compared with 33 high-intensity rainfall events that did not trigger regional landslide events in 2018. Results show that landslides occurred during high-intensity rainfall that coincided with the highest soil moisture values (estimated clays saturation point), according to Soil Moisture Active Passive level 4 (SMAP-L4) data. Our results demonstrate the potential of SMAP-L4 and GPM IMERG data for landslide hazard assessment and early warning where ground-based data are scarce. However, other rainfall events in the months leading up to Typhoon Mangkhut that had similar or higher rainfall intensities and also occurred when soils were saturated did not trigger widespread landsliding, highlighting the need for further research into the conditions that trigger landslides in typhoons.