José Lugo Hubp

The geomorphological evolution of the Paricutin cone and lava flows, Mexico, 1943–1990

Abstract Erosion and sedimentation processes in the Paricutin cone and adjacent lava fields have been evaluated 47 years after the eruption through field study of the morphological characteristics of the area. Previous studies indicate an initial stage of accelerated erosion, decreasing quickly after the stripping of the ash layers and cessation of the volcanic activities. In the cone and crater area, revegetation is the main process, after the first stage of stripping of fine ash. The lava fields are the least affected areas by erosional processes, with vegetation development in minor depressions, crevices and along the edges of the lava flows. The “llanos” or lava dammed plains, are the most active physiographic units, with continuous deposition of sediments. They are completely covered by vegetation or under agricultural use. Incision of channels along the lava field edge promotes the integration of the drainage system, but still most of the affected area drains into the lave field. Present erosion rates are higher than normal rates, and a complete rehabilitation of the pyroclastic area may extend over decades. Filling of sediments and revegetation of the lava fields will develop in a longer period of several millennia.

A GIS method for landslide inventory and susceptibility mapping in the Río El Estado watershed, Pico de Orizaba volcano, México

Abstract In volcanic terrains, dormant stratovolcanoes are very common and can trigger landslides and debris flows continually along stream systems, thereby affecting human settlements and economic activities. It is important to assess their potential impact and damage through the use of landslide inventory maps and landslide models. In Mexico, numerous geographic information systems (GIS)-based applications have been used to represent and assess slope stability. However, there is no practical and standardized landslide mapping methodology under a GIS. This work provides an overview of the ongoing research project from the Institute of Geography at the National Autonomous University of Mexico that seeks to conduct a multi-temporal landslide inventory and produce a landslide susceptibility map by using GIS. The Río El Estado watershed on the southwestern flank of Pico de Orizaba volcano, the highest mountain in Mexico, is selected as a study area. The geologic and geomorphologic factors in combination with high seasonal precipitation, high degree of weathering, and steep slopes predispose the study area to landslides. The method encompasses two main levels of analysis to assess landslide susceptibility. First, the project aims to derive a landslide inventory map from a representative sample of landslides using aerial orthophotographs and field work. Next, the landslide susceptibility is modelled by using multiple logistic regression implemented in a GIS platform. The technique and its implementation of each level in a GISs-based technology is presented and discussed.

Landslide inventory mapping and landslide susceptibility modeling assessment on the SW flank of Pico de Orizaba volcano, Puebla-Veracruz, Mexico

Volcanic regions with stratovolcanoes and monogenetic fields are very common and have the potential to trigger along their stream systems landslides and debris flows that damage human settlements, industrial development, cattle raising, forestry, and agricultural activities. However, a practical and standardized landslide mapping methodology using GIS for landslides that occur continually along the stream systems in volcanic terrains has not been applied in Mexico. As a result, landslide inventory maps and related geo-databases that support the prediction of future slope instability in volcanic terrains are lacking. Also, little work has been done on the systematic comparison of different models to predict landslide susceptibility. In this study, a landslide inventory map is derived from a representative sample of landslides using multi-temporal aerial-photo-interpretation and field investigations. The stability is modeled using LOGISNET (Multiple Logistic Regression, Geographic Information System, and Neural Network) as a tool to compare and contrasts the advantages and limitations of two landslides susceptibility models: Stability Index MAPping (SINMAP) and Multiple Logistic Regression (MLR). Both models are embedded in LOGISNET to predict landslides and facilitate the analysis. The validations of the resulting susceptibility maps were performed by comparing them with the inventory map in a contingency table. This research uses the stream system of the Rio Chiquito-Barranca del Muerto watershed as a case-study area. The study area is located in the SW flank of Pico de Orizaba, Volcano, Veracruz-Puebla.

Assessing Landslide Frequency for Landform Hazard Zoning Purposes

This work provides an overview of the on-going research project (Grant PAPIIT, no. IB100412-RR180412 and IPL project #170) from the Institute of Geography at the National Autonomous University of Mexico (UNAM). The project seeks to conduct a multi-temporal landslide inventory, analyze the distribution of landslides, and characterize landforms that are prone to slope instability by using Geographic Information Systems (GIS). The study area is the Rio Chiquito-Barranca del Muerto watershed that covers 111 km2 and lies on the south-western flank of Pico de Orizaba volcano. The watershed was studied using aerial photographs, fieldwork, and adaptation of the Landslide Hazard Zonation Protocol of the Washington State Department of Natural Resources, USA. A total of 571 gravitational features were recognized, of six types: shallow landslides, debris-avalanche, deep-seated landslides, debris flows, earthflows, and rock falls. This analysis divided the watershed into 12 mass-wasting landforms on which gravitational processes occur: inner gorges, headwalls, active scarps of deep-seated landslides, meanders, plains, three types of hillslopes classified by their gradient (low, moderate, and high), rockfalls, non-rule-identified inner gorges, non-rule-identified headwalls, and non-rule-identified converging hillslopes. For each landform the landslide area rate and the landslide frequency rate were calculated, as well as the overall hazard rating. The slope-stability hazard rating has a range that goes from low to very high. The overall hazard rating for this watershed was very high.

Mapping landforms for landslide hazards assessment on the SW flank of Pico de Orizaba volcano, Puebla-Veracruz, Mexico

Landslides that occur along stream systems are very common and have the potential to damage human settlements and economic activities. On the highest mountains in Mexico the potential for landslides and debris flows is great because of the large area of weakened rocks at high altitudes and under high seasonal rainfall. In Mexico, in spite of the effort to represent and assess slope stability by local authorities and scientists, there is a lack of standardized and systematized landslide inventory maps, landslide hazard maps, and related geo-databases that support the prediction of future slope instability. The present work illustrates a method to analyze the distribution of landslides and characterize landforms that are prone to slope instability. For the Río Chiquito-Barranca del Muerto watershed on the southwestern flank of Pico de Orizaba volcano, landforms and landslide distribution were ascertained through a landslide inventory map created from multi-temporal aerial photographs, field investigations and, an adaptation of the Landslide Hazard Zonation Protocol of the Washington State Department of Natural Resources, Forest Practices Division, in a GIS-based technology. This analysis divided the watershed into 12 mass-wasting landforms that were assigned slope-stability hazard ratings from low to very high. The overall hazard rating for this watershed was very high.

An Overview of a GIS Method for Mapping and Assessing Landslide Hazards

In Mexico, numerous GIS-based applications have been used to represent and assess slope stability. However, there is not a practical and standardized landslide mapping methodology under the GIS system. This work aims to illustrate a comprehensive methodology to characterize areas that are prone to slope instability. The Rio Chiquito-Barranca del Muerto watershed on the southwestern flank of Pico de Orizaba volcano, the highest mountain in Mexico, was selected as study area. The study area has a combination of several contributing factors to landslides such as high rain fall during the wet season, rock types, high degree of weathering, and steep slopes.