A wide caldera sits at the top of the volcano. The highest point of the volcano lies east-northeast of the caldera and reaches elevation. The caldera has an incomplete rim and is filled with snow, leaving a wide depression. The rim of the caldera is covered by volcanic ejecta including lapilli and lava bombs, probably the products of the most recent eruption of Mount Melbourne, which overlie a thick layer of pumice lapilli. Three small, nested craters formed by phreatomagmatic eruptions occur on the southern rim of the summit caldera. Pyroclastic fall deposits crop out in the northern rim of the caldera and there are more alternating lava-tephra sequences elsewhere in the summit region. There is evidence of past structural instability (collapse structures) on the eastern and southeastern flank and an arcuate high scarp on the eastern flank appears to be an incipient sector collapse.