The Cartographic and Geological Institute of Catalonia (ICGC) has installed a control network in a fissure in the Riscal de Castellfollit de la Roca to detect if there is movement. The fissure is under Carrer de la Plaça and has an opening greater than 50 centimeters and a vertical continuity of 17 meters. Now, the cartographic institute has placed nine fissurometers, five clinometers and two rock temperature sensors. These 16 devices make it possible to obtain measurements with a precision of hundredths of a millimeter and will serve to anticipate movements that could end up with a greater detachment.
The Territory Department, the Girona Provincial Council and the Castellfollit de la Roca City Council promote a Comprehensive Conservation Plan for the Cinglera that exists in the municipality. This should ensure the safety and preservation of the old part of the town, located on the riscal. The Cartographic and Geological Institute of Catalonia carries out regular monitoring with drone inspections and the generation of high-resolution 3D models.
In addition, the ICGC carried out a catalog of discharges to determine preferential surveillance areas. One of them is the riscal sector under Carrer de la Plaça. At this point there is a fissure only 50 centimeters wide, but 17 meters deep. This July it was decided to install a control network that allows monitoring the movement of the rock in this fissure.
The network consists of sixteen devices that measure movement with a precision of hundredths of a millimeter. This information collected by the control network is uploaded to the ICGC servers so that researchers can continuously monitor the evolution of this fissure. This information obtained makes it possible to optimize the risk preservation strategy. In addition, it can advance future movements that could end in larger landslides and, therefore, gives investigators and authorities greater room for maneuver.
This Thursday it has also been agreed that the ICGC will carry out a study of alternatives to see what would be the most feasible option to carry out a pilot stabilization test in one of the existing sectors.
In addition to contact instrumentation, for some years the ICGC, with the collaboration of the RISKNAT research group of the University of Barcelona (UB), has been carrying out periodic terrestrial laser scanner (TLS) campaigns. This technique makes it possible to detect even landslides that go unnoticed with the naked eye and also signs of instability, in the form of small movements.
The ‘basaltic ridge’ on which the old town of Castellfollit de la Roca sits is one of the most relevant testimonies of volcanism in Catalonia and, given its uniqueness, it is listed as an Area of ??Geological Interest and is also included in the catalog of outcrops of interest of the Special Plan that regulates the Area Natural Park.
