Paper on Tensile Strength published in GRL

​Knowledge of the tensional strength of rock is important for mining and construction, e.g. tunneling and for various research fields in earth science.  However, laboratory tests of tensional strength are difficult to perform and it is not clear how the strength of small intact rock samples determined in the laboratory scales to larger rock masses, which include cracks and imperfections.  In this paper, Sigurjón Jónsson estimates tensional rock-mass strength of granitic​ rocks on a kilometer scale by using InSAR observations from satellites. This is the first time that InSAR observations are used for this task. The different component radar data were used to derive 3D surface displacements and then to calculate the different components of the surface strain-change tensor.  By comparing the maximum tensional strain on the surface with the occurrences of tensional fractures on the ground, bounds were put on the tensional strength of the surface rocks.