How does anisotropy in bedrock river granitic outcrops influence pothole genesis and development?

Pothole formation and development may be influenced by joint sets and other heterogeneities within bedrock, as well as by hydraulics. Previous research indicates that most potholes found in rivers of the mountainous Spanish Central System exhibit preferred orientations associated with dominant joints and correlate more strongly with variations in substrate resistance than with hydraulics. Weathering and erosion weaken rock surfaces, which leads to decreased mechanical resistance. We start from the hypothesis that different mechanisms of pothole formation may create around the pothole a distinctive signature in terms of ultrasound pulse velocity and surface hardness. We develop a conceptual model and test it using potholes for which we know the