Debris Sliding Monitoring Using Permanent Interferometry Disperser Technique in the Chosica-Lurigancho District, Perú, 2020

Every year in the period from January to March, the constant rains produced by the El Niño phenomenon destabilize the terrain of the streams of the capital of the Lurigancho district, Chosica, located in Lima, Perú. Due to the heavy rains, many landslides occur in the different streams of Chosica. Although there are records of landslides every year, the last events recorded in Chosica occurred from January 14 to March 19, 2017. This study applies the Persistent Scattering Interferometry Synthetic Aperture Radar (PSInSAR) technique to estimate landslide displacement. Our study area includes 24 km2, emphasizing the Carrosio and Corrales streams. This research uses images of Terrasar-X, 19 scenes in ascending orbit and 20 scenes in descending orbit, from April 2020 to December 2020. This study has been worked with the PSInSAR technique, based on the InSAR time series. Considering the Chosica Landslide as a very slow-moving debris flow, this technology has acquired line-of-sight (LOS) deformation. First, the orbital displacement result has been obtained by processing with ENVI’s 5.3-Sarscape tool. Later, both orbits were spatially combined to obtain vertical (top–bottom) and horizontal (east–west) displacement using the ArcGis-Python tools. High consistency was achieved between the descending orbit and ascending orbit displacement results. A slight deformation of − 8 mm/year to − 21 mm/year was found in the area of interest in the Carrosio and Corrales streams, results obtained in the PSInSAR processing with descending orbit. While ascending orbit, possible areas prone to slipping of debris were identified with values of 8 mm/year to 10 mm/year. Subsequently, the integration of displacement data in ascending and descending orbits was carried out. As a result, we obtained a slight displacement of 0.10 mm/year to 0.16 mm/year of horizontal displacement and 0.10 mm/year to 0.19 mm/ year of vertical displacement. We conclude that the monitoring carried out throughout 2020 has not detected displacement. This research on monitoring Chosica área was made cause every year in this zone. We have heavy rain from January to March, so we need to monitor the area to prevent disasters. During the landslide monitoring of the year 2020, the analysis of results showed an insignificant displacement, and during the same period, no landslide events were reported by governmental authorities. Nevertheless, it is recommended to continue observing the area to prevent future debris flow in Chosica.