Zonificación de la amenaza por movimientos en masa en 1.5 Km de la Quebrada Carretas, Parroquia Carcelén, Distrito Metropolitano De Quito.

Abstract

Inside Distrito Metropolitano de Quito, DMQ, the area of slopes of ravine and rivers has increased in recent years, putting buildings and population located on the margins at risk. The Quebrada Carretas is located in the Monjas river basin, along the Monjas river tributaries are affected by landslides effect caused in times with high rainfall (Rivera, 2016). This academic work is focused on zoning the hazard by landslides in 1.5 km of the Quebrada Carretas whose trigger factor is an earthquake, through the application of the Newmark Methodology, (1965) and Arias Intensity, (1970). Newmark's methodology seeks to integrate the characteristics of the area such as lithologies, geotechnics and geological details that are integrated into a geographic information system for analysis and interpretation, determining Safety Factor and Critical Acceleration values. The methodology allows zoning the hazard in the face of the horizontal displacement produced when a seismic event is generated using the Arias Intensity. Through field trips and observation of orthophotos, the Fm. Cangahua, which is located throughout the study area, in addition, through the bibliographic compilation, the essential geotechnical values were obtained to apply the methodology. Likewise, with the help of an Unmanned Aerial Vehicle and the Tomorrow's Cities Project, a Digital Elevation Model (DEM) with a resolution of 0.2m and a DEM with a resolution of 2m were obtained in order to obtain the geomorphology of the area. Arias Intensity uses two international earthquakes Loma Prieta Mw 6.9 and Coalinga Mw 5.7, which meet the DMQ conditions based on the geological and tectonic properties such as the reverse Fault System of Quito, Vs30 between 360 to 600 m/s and an epicentral distance of 10 – 30 km. The results obtained with the studies of Merino, (2018) and Benítez, (2018) were simulated and compared. By applying the logarithmic formula proposed by Hsieh and Lee, (2011) that integrates the values of Critical Acceleration and Arias Intensity for the international earthquakes, the Newmark displacements are obtained to proceed to zone the hazard due to earthquake-induced landslides, determining areas of very high (> 15 cm) and high hazard (5-15 cm) for the Loma Prieta and Coalinga earthquakes, respectively. The areas that are affected by landslides resulting from intense rain activity and erosion at the foot of the slope coincide with the areas of very high and high hazard, these being the most affected when a seismic event is generated.