Calculation of precipitation and seismicity thresholds as triggers for mass movements in the region of Bucaramanga, Colombia

DInSAR Multi-Temporal Analysis for the Characterization of Ground Deformations Related to Tectonic Processes in the Region of Bucaramanga, Colombia

“…These states of deformation provide basic arguments in the construction of scenarios for the evaluation of these unstable conditions on surfaces (mass movements), as these conditions are measurable in the first place by the inherent relationships that develop between the attributes and their variables such as geology, geomorphology, land cover and land use that model this spatial behavior or susceptibility [78][79][80][81][82]. Then, the factors that trigger mass movements can be integrated into these conditions of susceptibility, changing the analysis to a spatiotemporal or hazard aspect, where intense rains, rapid snowmelt, changes in water levels, volcanic eruptions or strong shaking of the ground by the action of an earthquake are the major precursors [83], and within these scenarios, rainfall and seismic activity are the most recurrent factors for conditions that pose the threat of mass movement [29,80,82,84].…”

“…Parallel to this work, a geometric construction of the undocumented movements is carried out by means of a process of photointerpretation carried out on images arranged on the Google Earth ® platform [88,89]. Each of the mass movements is assigned the date of occurrence of the event based on the information recorded in the databases of DesInventar, SIMMA and UNGRD, in addition to the information reported by sources such as newspapers and regional news [84].…”

“…This is because, under these conditions, the most favorable scenarios for the creation of planes of instability would occur. In addition to this, the relationships generated in the study by Valencia Ortiz and Martínez-Graña [84] were also taken into consideration for the present analysis, with reference to seismic events that trigger mass movements (Figure 9). From this it is observed that there are no points of convergence The inventory of mass movements is correlated with the multi-temporal sequences of the differential interferograms of LOS-ascending and LOS-descending created by the 50th percentile.…”

“…All these considerations within the study of susceptibility to mass movements guarantee a more complete analysis based on the variables contemplated that are directly related to the conditioning action of a mass movement, which guarantees the creation of a model more in line with the situation present in the environment [31,82]. Finally, it is important to mention an aspect of the study carried out by Valencia Ortiz et al [84], which describes how seismic activity and rainfall are relevant factors that act as a trigger for mass movements for the study region. This study established a combined effect between seismic activity (Mw ≥ 4) and rainfall, with a threshold of 53 mm for 24-h rainfall and 158 mm for accumulated rainfall from the previous 15 days in a 25-year return period, thus giving a spatiotemporally framed scenario.…”

Evaluation of Susceptibility by Mass Movements through Stochastic and Statistical Methods for a Region of Bucaramanga, Colombia

“…On the other hand, regarding the evaluation carried out of the susceptibility that has been well-described as a spatial element of the inherent factors of the terrain, it can be extended to a spatiotemporal or hazard level, where the triggering factors are included in temporal terms. In this context, the study by Valencia Ortiz et al, [96] which was focused on this region and evaluated the conditions of rainfall and seismic activity as triggers of the MMs. For this study, a characterization of the rainfall was carried out, obtaining a threshold of 53 mm for 24 h rainfall and 158 mm for accumulated rainfall of 15 previous days.…”