An extremely large, caldera- or trough-like, collapse depression, that is usually surrounded by extensive ignimbrite sheets. One of the largest such depressions is in the Taupo region of N. Island, New Zealand, and measures 100 × 30 km. Other well-known examples occur in the western USA (e.g. the Yellowstone volcano-tectonic depression) and the Philippines (the Lake Toba volcano-tectonic depression).
Subjects: Earth Sciences and Geography.