The HRSC image highlights linear, deep depressions on the surface known as Coloe Fossae – a well-defined graben system shaped by the planets internal forces. These grabens extend from north (right side of the image) to south (left side) and are separated by raised blocks of crust known as horsts, forming what geologists call a typical horst and graben structure (see annotated image). The surrounding terrain features several large impact craters, as well as smaller ones. Clusters of small craters, known as secondary crater fields, are also visible (see annotated image). These irregularly shaped secondary craters are formed when material is ejected during a larger impact event and then falls back to the surface. Secondary craters often appear as crater chains or, as seen in this image, as clusters located near the primary impact crater. On planetary bodies other than Earth, impact cratering is a key surface-modifying process. By analyzing the size and frequency of craters, scientists can estimate the relative ages of surfaces. Fewer craters generally indicate a younger surface that has been modified or resurfaced more recently. The significantly fewer impact craters on the graben floors suggest that these deposits may be relatively young compared to the heavily cratered surrounding terrain.