2008 Alum

Isaiah Corley

Isaiah Corley

Years participated in RESESS:

An Overview

Modeling rainfall thresholds for landslide analysis

Academic Affiliation: Junior, North Carolina A&T University Geology
Science Research Mentor: Rex Baum – USGS
Writing and Communication Mentor:Adrian Borsa – UNAVCO


This research intends to successfully analyze landslide behavior by using a deterministic analysis of rainfall thresholds. An alternative approach for defining rainfall thresholds uses deterministic models for rainfall infiltration and slope stability testing. Deterministic modeling is believed to be less computationally costly than the empirical method. This project aims to define rainfall thresholds in Western Oregon by applying the deterministic modeling technique. The objectives are to use a computer model of landslide initiation and rainfall infiltration to define rainfall thresholds for certain sites in Western Oregon and to compare these thresholds with historically collected rainfall threshold and rainfall amounts data.

The project can be divided into subcategories: define landslide provinces based on similar climate, terrain, and geology; compile a database of relevant geotechnical parameters for selected provinces; model rain infiltration and slope stability for representative rainfall intensities and durations, geotechnical parameters, soil thicknesses, and slope angles for selected provinces; define thresholds based on model results; and compare rainfall thresholds defined by computer modeling with published empirically defined thresholds and actual landslide events. Two areas of major research are discussed: the rainfall threshold analysis methods, and how they can be used by the TRIGRS (Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability Analysis) program to compute a factor of safety.