United States Geological Survey
"Aerial view of a lava dome nestled within Panum Crater, which was built by the explosive ejection of tephra. The explosive eruptions also generated three pyroclastic flows and a surge, and built the ring of tephra that surrounds the Crater. The dome was the last lava flow erupted during Mono eruptive episode between A.D. 1325-1365." U.S. Geological Survey
Panum Crater is a volcanic cone located south of Mono Lake (See Day 203: Tracing the Pleistocene) in California.