Lassen Summit Area View northward from the summit of Lassen Peak showing the eruptive crater of May 1915, which remained open throughout the eruptions of May 19-20 and May 22. In the foreground is the lava flow of May 19-20, which in part oozed viscously back into the open crater after the eruption of May 22. Large blocks on the surface of the lava flow were ejected from the crater during the May 22 event. The rim of the crater in the background is marked by remnants of a lava dome erupted into the crater between May 14 and May 19 but ejected during explosive reopening of the crater early in the eruption of May 19-20. Photo by R. L. Christiansen, July, 1984.