The term 'Deep Crack' can be defined as a FISSURE, which is a long, narrow opening or line of breakage made by cracking or splitting. Fissures are typically formed in rocks and other hard materials due to the effects of weathering, erosion, or tectonic forces. They can also be caused by natural disasters such as earthquakes, volcanic eruptions, and landslides. Fissures can also be found in man-made structures, such as buildings, bridges, and dams. Fissures can range in size from microscopic to several meters wide.