Análisis del riesgo kárstico en medios urbanos asentados sobre depósitos aluviales cementados (mallacán )e n la Cuenca del Ebro (España) Karstic hazard analysis at urban areas over cemented alluvial deposits (mallacán) in the Ebro Basin (Spain)

Active karst processes in urban settings can represent a significative hazard for the population and to buildings and other facilities. In this work, an integrated analysis by means of geophysical survey, surficial analysis and geomechanical tests is presented. The obtained results permit to identify a collapsed geometry where the more sudden hazards are related to the noncollapsed marginal areas of the sinkhole. The geomechanical tests show a high alluvial resistance due to the partial carbonatic cementation with ap parent higher stability. However, cementation allows the individualization and the propagation of underground cavities up to near-surfacelevels being the highest hazard to be analyzed in these contexts.