BackgroundA large group of tuff rings, tuff cones, and maars occupies the Fort Rock-Christmas Lake Valley basin S of Newberry volcano. The 64 x 40 km basin was occupied a Pliocene to late-Pleistocene lake, through which eruptions of basaltic magma occurred along faults cutting diagonally across the basin and adjacent highland. The volcanic field is named for Fort Rock, a spectacular wave-cut tuff ring that was breached by wave erosion. The Table Rock tuff ring and maar complex lies at the SE end of the field. Spectacular maars such as Hole-in-the-Ground and Big Hole are located near Gighway 31. Hole-in-the-Ground was formed as recently as between 13,500 and 18,000 years ago.
Source: Smithsonian / GVP volcano information
See also: Sentinel hub | Landsat 8