In 1981, geologists suggested that volcanism at Piton des Neiges may be closely linked to regional structural geology. The main point of eruptive activity is associated with rift zone strike-slip faults and dike swarms around the mountain indicate cauldron subsidence. Structural characteristics help to explain the dramatic erosion of the central caldera, which collapsed due to graben formation. In addition, the eruption of younger lava flows may have emptied the magma chamber, helping to drive the collapse.