Results of Recent Monitoring Activities on Landslide Umka, Belgrade, Serbia—IPL 181

Results of recent monitoring activities conducted from 2014 to 2019 are presented in the paper as a part of IPL 181 Project progress report. Recent monitoring activities are concentrated on several landslide monitoring techniques—automated GNSS monitoring system measurements, geodetic benchmark survey monitoring, UAV imaging, processing and analysis, and PSInSAR data processing and analysis. Results of all monitoring activities were analysed and used for cross-correlation and for verification of monitoring results obtained from different techniques. Displacement rates from GNSS measurements indicate that object point UmkaGNSS2 has moved 0.30 m towards the North and 0.50 m towards the West, while the vertical displacement was approximately −0.15 m for the 2014–2018 time span. Similar range of GNSS displacement rates were found in previously published results from monitoring activities realized from 2010–2014. PSInSAR data analysis also showed good correlation between nearest PS points and GNSS point for the same period of monitoring. Results from UAV and geodetic benchmarks survey showed very good correlation in displacement vectors’ direction. According to the analyzed data it could be concluded that all monitoring results are in compliance with previous research results and confirm that the Umka is slow to very slow moving landslide with cyclic acceleration and deceleration phases.