Giant Crater 26. Aerial view north-northeast across the upper part of map unit bgc, the basalt of Giant Crater, which erupted about 12,500 years ago in early postglacial time on the south side of Medicine Lake volcano. Giant Crater, visible in lower left center, is one of four vents for the unit; all vents are aligned on a single east-northeast trend. Diameter of crater is approximately 0.25 km. Chimney Crater, uppermost of the four vents, is located at the upper right side of the photo. Lava tube from Chimney Crater skirts east side of Giant Crater; tube marked by collapse at lower left side of Giant Crater can be traced approximately 25 km to south. Photograph by Julie M. Donnelly-Nolan.