Side-scan surveys of South Chamorro Seamount show a major southeastern sector edifice collapse, with debris flows of serpentine material (dredged in 1981 and observed by submersibles in 1995) that blankets the slope of the trench from summit to axis. The true summit of the volcano sits above this collapse; its formation was likely tied to the collapse. Submarine observation of the summit show that the summit knoll is broken up into slabs of serpentine mud, with meter-deep fissures arranged in a crosscutting orientation.
