Doctoral Dissertation Research: Rainfall Characteristics and the Influence of Urban Land Use on Shallow Landslide Initiation in Seattle, Washington

天然山坡上的浅层滑坡常发生在强度大或持续时间长的暴雨期间。虽然研究人员研究了城市环境对地表水文和排水形态的深刻影响，但相对较少关注城市化对滑坡灾害的影响。这项博士论文研究项目将研究不透水表面对西雅图浅层滑坡发生的影响，西雅图是一个降水气候区，以持续时间长、强度小的冬季暴雨为特征。该项目将使用地理信息系统(GIS)框架，将来自密集量规网络的降雨量数据、高分辨率数字地形、滑坡发生的历史记录和不透水表面的遥感地图结合在一起。对这些数据的分析将有助于评估流域尺度上地表排水改造对滑坡易感性的影响。研究方法将包括汇编历史上浅层滑坡的发生情况和相关的降水气候学。将定义降雨强度/持续时间之间的经验关系。对大型或近期滑坡的实地调查将提供有关地质背景、滑坡破坏和沉积的类型以及排水改造的影响的信息。为了评估防渗面对滑坡发生的影响，将使用降雨-入渗/斜坡-稳定性耦合模型来描述已知发生滑坡的暴雨期间深层孔隙水压力的空间分布。该项目将通过在地理信息系统框架中应用基于物理的耦合模型来研究在低强度和持续时间长的暴雨期间发生斜坡破坏的城市环境中不透水面对滑坡危险性的影响。这项研究将阐明城市环境对分水岭尺度上的山坡过程产生重大影响的过程。在更广泛的背景下，该项目将增加对人类对地貌系统影响的了解。这项研究的结果应该为应急管理和规划提供预测性和设计性工具。作为博士论文研究改进奖，该奖项还将提供支持，使有前途的学生建立一个强大的独立研究生涯。

Shallow landslides often occur on natural hillslopes during rainstorms of high intensity or long duration. While researchers have examined the profound effects that that an urban environment can have on surface hydrology and drainage morphology, relatively little attention has been given to the effects of urbanization on landslide hazards. This doctoral dissertation research project will address the influence of impervious surfaces on shallow landslide occurrence in Seattle, an urban area with a precipitation climatology characterized by winter rainstorms of long duration and low intensity. The project will use a geographic information system (GIS) framework to combine rainfall data from a dense gauge network, high-resolution digital topography, a historical record of landslide occurrence, and a remotely sensed map of impervious surfaces. Analyses of these data will facilitate evaluation of the watershed-scale effects of surface drainage alteration on landslide susceptibility. Research methods will include compilation of historical shallow landslide occurrence and associated precipitation climatology. Empirical relations between rainfall intensity/duration will be defined. Field investigations of large or recent landslides will provide information on the geologic setting, style of landslide failure and deposition, and influence of drainage modifications. To evaluate the effect of impervious surfaces on landslide occurrence, a coupled rainfall-infiltration/slope-stability model will be used to describe the spatial distribution of pore-water pressures at depth during rainstorms in which landslide are known to have occurred.This project will examine the influence of impervious surfaces on landslide hazard in an urban setting where slope failure occurs during rainstorms of low intensity and long duration by applying a coupled, physically based model in a GIS framework. The study will illuminate the processes through which the urban environment has a significant impact on hillslope processes at the watershed scale. In a broader context, the project will add to the understanding of human impact on geomorphic systems. Results from this study should provide predictive and design tools for emergency management and planning. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.