Figure 6-39 Scarps on Mercury A long, meandering cliff, called Santa Maria Rupes, runs from north to south across this Mariner 10 image of a region near Mercury’s equator. This cliff, called a scarp by geologists, is more than 1 km (0.6 mi) high and runs for several hundred kilometers. Note how the crater below the center of the image was distorted vertically when the scarp formed.