Resumen

ORDAZ HERNANDEZ, Alexis; ESQUIVEL ARZATE, Rosaura Karina; HERNANDEZ SANTANA, José Ramón  y  CABADAS BAEZ, Héctor Víctor. Susceptibility to rock landslides in the La Teresona-Zopilocalco Norte suburb of Toluca: assumptions for community development. Invest. Geog [online]. 2019, n.99, e59888.  Epub 25-Sep-2019. ISSN 2448-7279.  https://doi.org/10.14350/rig.59888.

In the last half-century, the world scientific community, government authorities, and civil society have paid particular attention to environmental management, land-use planning, use of alternative energies, and many other guidelines, seeking to safeguard and improve environmental quality, preserve biodiversity, and ensure sustainable development. This vision of development requires consistent policies, where all urban development, land-use management, productive, and social actions, among many, focus on meeting the needs of the current population and future generations, in a way that is harmonized with the natural conditions and resources, especially at the local level.

In this regards, it is understandable that the analysis of the dangers of natural genesis, including mass removal processes, is a prerequisite to achieving sound land-use and urban-planning policies for the establishment and development of safer communities, where the free fall of rocky debris through steep slopes do not threaten the physical and social vulnerability of these communities.

At the international level, authors like Tanarro and Muñoz (2012) have elaborated geo-referenced inventories of rock falls in the Duero river basin for comparison with other geological-geomorphological parameters, and like Antoniou and Lekkas (2010), who used engineering and geological information, structural analysis, and geomorphology to elaborate maps on the likelihood of reach of boulders and determine the susceptibility of at-risk human activities.

The growth of settlements in urban outskirts in Mexico has led to the occupation of land of complex geomorphological and geological conditions, specifically in mountainous systems in volcanic buildings. This is the case of the centralnorth suburbs of the city of Toluca (La Teresona-Zopilocalco Norte), where 21687 inhabitants currently live. This urban sector occupies a stretch of 4.0 km along Paseo Matlazincas, a roadway used as reference to delimit the area of study, from the highest mountain tops located to the north of the roadway; to the south, the limit was drafted at 2690 m a.s.l., which marks a significant difference on terrain slope. Along this corridor, cracks in the asphalt layer of some roadways, cracking of household walls, and fallen rocky blocks of approximately 2.5 m in diameter that at times have impacted Paseo de los Matlazincas, the main communication roadway. Given this situation, it is essential to the elaborate maps on the degrees of susceptibility to rock landslides to make decisions for the implementation of prevention or mitigation measures within a context of local planning addressing the most threatened priority sites.

The research process for the analysis of susceptibility to rock landslides is carried out in three phases: 1. Data collection and analysis of information directly related to rock landslides; 2. Elaboration of the thematic cartography on the determinants of this geomorphic process and its integrated analysis; and 3. Validation of field results. The analysis of susceptibility to rock landslides includes criteria related to lithology, morphostructure, occupation, and land use, which were inventoried. The inventory form used allowed the tabulation of physical elements that are key for the interpretation of gravitational processes, with an emphasis on rock landslides, namely: (1) location, including the geographic coordinates; (2) description of the geological material; (3) structural analysis of slopes, including measurements of dip direction and angle of lava flows or strata, as well as structural measurements of planes of failures; (4) type of event (detachment, sliding, overturning, or flow); (5) current state of the event (active or inactive); and (6) damage caused.

The integration of these variables revealed five levels of rock landslide susceptibility: very low, low, medium, high, and very high. The results obtained show the unfavorable characteristics of the area for the development of urban infrastructure.

The susceptibility analyses conducted clearly show that this urban area is unfavorable for the development of large infrastructures, such as hospitals, schools, shopping malls, and even for household development and roadways. Currently, poor urban planning and disregard of the geomorphological conditions in the site have led to a scenario of building vulnerability, with 4270 households under conditions of medium, high, and very high susceptibility to landslides, which are home to 15796 persons. This degree of exposure causes a systematic impact on local development, as observed in this study, with damages to both buildings and roadways.

Palabras llave : Susceptibility; rockfalls; local development; Toluca; México.

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