Global Volcanism Program | Image GVP-00399
The SE wall of Red Crater is cut by a vertical volcanic dike that fed eruptions along a NE-SW-trending fissure. Magma along the outer part of the dike cooled against the red scoria walls, while magma at the center of the dike partially drained away, leaving this cavity. Ngauruhoe is visible in the background. These are two of more than a dozen cones and craters forming the Tongariro volcanic complex.
Photo by Jim Cole (University of Canterbury).