ABSTRACT
The slope stability of altered rocks that can behave as soils (generally referred to as “soft rocks”) can be a major concern when these slopes are surrounding key infrastructures. This paper describes the role of satellite technologies, and specifically InSAR (Interferometry of Synthetic Aperture Radar), as a tool for monitoring precursor ground displacement in the case of a massive slope in Northern Spain affecting a major European link highway. The slope failed at least two times in the period between March and November 2015. The first failure resulted in the highway blocked and the necessity of implementing an emergency project and remediation works. During the remediation works a second failure occurred.
The geological profile of the site is made of alluvial soils, altered rock mainly due to previous landslide in the same area, and rock mass, also affected by faulting, made by breccia, limolite and mylonite.
A stack of images from the European Space Agency satellite Sentinel was processed for a period starting before the first failure and up to several months after the highway reopening. This ground motion analysis aimed to help understand the mechanism of failure as well as the precursory movements before the failures.
