Comparative Analysis Landslide Modeling Approaches:
Probability Likelihood Ratio vs. Heuristic "Expert-driven" Approach
A case study for Baguio City

Digna G. Evangelista¹, Federico C. Jacoba¹, Marie Iris P. Villanueva¹ and Claro Jose C. Manipon²

¹Sr. Science Research Specialist,
²Supervising Science Research Specialist
Mines and Geosciences Bureau

Abstract

Landslide hazard zonation using GIS desktop mapping technique was done using two basic approaches: 1) use of defined values quantitatively measured (Probability-Likelihood Ratio), and 2) use of heuristic or ‘expert-driven" approach wherein values are measured qualitatively. These values are weights given to a specific attribute of a thematic map as contributor to a landslide event.

The analysis uses ILWIS for GIS manipulations. The scale of maps used is 1:10,000. The output maps both display Low, Moderate, High and Very High Susceptibility zones for landslide occurrences. No significant variation is observed on the two maps; the Highly Susceptible landslide prone areas were showing the same spot on the two maps, but with slight differences in lateral dimensions. Although statistical analysis for landslides gives more accurate results, the existing method of Mines and Geosciences Bureau (MGB) for such analysis is efficient in predicting landslides in the absence of available landslide inventory data.