Sector collapse
A sector collapse or lateral collapse is the structural failure and subsequent collapse of a minimum volume of 1 km3 (0.24 cu mi) of a volcano. Unlike smaller flank collapses, a sector collapse can involve the central volcanic pipe and historically this term had been restricted by some writers to such events in arc stratovolcanoes, but is now used for large events in any volcano. Sector collapses are one of the most hazardous volcanic events, often resulting in lateral blasts, landslides, and changes in volcanic eruptive behavior. Sector collapse can be caused by earthquakes, volcanic eruptions, gradual volcanic deformation, and other processes. Sector collapse events can occur on volcanoes at convergent and divergent plate boundaries. Sector collapses are generally very sudden; however, some attempts have been made to predict collapse events.