What is described as the upper surface of a slide in geological terms?

The upper surface of a slide in geological terms is known as the head scarp. This term refers specifically to the distinct and often steepened area at the top of a landslide or slide, marking the location where the material has detached from its original position. The head scarp generally indicates the point of failure and is a key feature in the assessment of landslides, as it provides valuable information regarding the movement and dynamics of the slide.

Understanding the features associated with landslides, such as the head scarp, is crucial for geology and civil engineering, especially in evaluating risks and implementing mitigation strategies for slope stability in various landscapes. The head scarp is often accompanied by other geological indicators, but it distinctly identifies where the sliding action initiates, making it essential for geologists and planners dealing with slope-related hazards.