volcano-tectonic depression

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volcano-tectonic depression 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 volcanotectonic depression).