Landslides in Tijuana, Mexico: hazard assessment in an urban neighborhood

Abstract

Context: The landslides in Tijuana, Mexico, destroy a large number of structures and infrastructures each year, producing large losses in various sectors of the economy. Method: In this study, we carry out a quantitative assessment of the landslides hazard in a neighborhood of the city that was affected by a landslide in 2010 and shows signs of terrain instability that warn about the possibility of new landslides. The hazard was calculated using the spatial probability, based on the susceptibility of the terrain to landslides, and the temporal probability using a database of events that occurred at sites near the study area. We apply deterministic methods based on the analysis of slope stability to calculate susceptibility, and we estimate the temporal probability using probability models that consider the occurrence of independent random events. Results: it was obtained that more than 50% of the study area presents a high landslides hazard of for return periods of 5, 10, 15 and 20 years, and it is demonstrated that the seismicity, topography and geotechnical properties of the soils, they are the factors with the greatest influence on terrain instability. In addition, it was determined that the areas of potential landslides are in soils whose resistance has been reduced due to the presence of underground flows produced by the infiltration of water through existing cracks and fractures in the terrain. Conclusions: the application of the described procedure made it possible to quantify the landslides hazard in the Laderas de Monterrey neighborhood for four return periods and to identify the factors with the greatest influence on the occurrence of these phenomena. The results obtained are an important step to analyze and evaluate the risk that landslides represent for structures, infrastructures, and people exposed to the impact of these phenomena; and they are a valuable tool for decision-making related to risk management and the establishment of regulations on land use in the area.