A survey of 581 sites found that 78% had active slope movements, helping identify where prevention efforts could be focused.
The Geotechnical and Environmental Research Group assessed 581 sites across Ocaña using historical records, field inspections, geographic information systems and drone imagery. The team documented the type of slope failure, existing stabilization measures and vulnerable elements.
The updated map identified areas that were not included in earlier assessments, including some previously classified as stable. Inadequate slope cuts and poor stormwater management were the most common reported triggers, while Simón Bolívar had the largest number of active areas.
Where slopes are moving
Of the 581 sites assessed across 46 neighborhoods, 78% had active mass movement phenomena, primarily landslides and rockfalls. Simón Bolívar had 65 active areas and an affected area of 3,500 square meters, equal to 11.71% of the neighborhood’s total area.
The researchers reported that 43 of 51 neighborhoods with a history of these problems still had active slope movements, and three additional neighborhoods contained highly prone areas. Comparisons with the 2015 assessment showed different patterns across Ocaña’s zones. In the Eastern Zone, the number of active sites was nearly unchanged, but at least 37 sites previously classified as susceptible had become active. The Central Zone had fewer active sites, while the Northern Zone included an increase in active sites in Colinas de la Esperanza, from six to 11.
The study also found that 95.65% of residents in the 46 communities identified as landslide-prone had not received risk-awareness or training from the responsible agencies.
Why the map matters
The updated map gives Ocaña’s risk-management authorities a more current inventory for prioritizing prevention and mitigation actions. The identification of newly affected areas, including places previously considered stable, shows why the researchers say these assessments need to be updated as the city expands on hillsides.
The findings also point to practical concerns identified in the survey: slope cuts made for construction and inadequate stormwater management were common factors associated with active slope failures. The reported lack of community training supports the researchers’ call for greater public awareness in vulnerable areas.
Evidence and caveats
This was a site-mapping and field-assessment study, not a controlled experiment. Researchers compiled historical records, visited sites using a standardized slope form, and used geographic information systems and drone photographs to assess conditions at 581 locations. They also compared the updated results with data collected through 2015 using statistical tests.
The evidence identifies locations, observed movement types and reported contributing factors, but the study does not establish that any single factor caused a particular landslide. The provided material does not describe the map’s measurement uncertainty, independent validation or how conditions may change after the assessment. The findings therefore provide a current risk inventory for Ocaña rather than a prediction of when individual slope failures will occur.
