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andesites of theDiller sequence
rhyodacite flow ofDersch Meadows
CrescentCrater
Hat Creek
Hat Creek
Lost Creek
Devastated Areaparking lot
Devastated Area
Survivors Hill(moraine)
dacite of Lassen Peak
moraine
EmigrantSummit
andesite of Hat Mountain
andesite of Hat Mountain
rhyodacite of Kings Creek(pyroclastic flows)
Raker Peak
rhyolite of Raker Peak
andesite of Raker Peak
Devastated AreaView looking northeast from summit of Lassen Peak (Lassen Peak quadrangle). Avalanche and debris-flow deposits of May 19–20, 1915 (unit sw9) as well as pyroclastic-flow and fluid debris flow deposits of May 22, 1915 (unit pw2) swept down the northeast face of Lassen Peak. These 1915 deposits overly the lithic pyroclastic-flow deposit (unit pfl) from partial collapse of the dome of Lassen Peak (unit dl, 27±1 ka) and also cover the paired moraines (unit Qta) on both sides of the Devastated Area. On the east bank of Hat Creek, pyroclastic flows of the rhyodacite of Kings Creek (unit rk, 35±1 ka), andes-ites of the Diller Sequence, undivided (unit ad, 400–470 ka) of Brokeoff Volcano, and the rhyodacite of Dersch Meadows (unit rd, 193±11 ka, part of the Bumpass sequence) are mantled by till (unit Qta). The dacite of Crescent Crater (unit dc, 236±1 ka) is also part of the Bumpass sequence. The upper part of Raker Peak is the andesite of Raker Peak (unit arp, 270±18 ka, part of the older Twin Lakes sequence), underlain by the rhyolite of Raker Peak (unit rr, 588±69 ka, part of the Rockland caldera complex). Forested slopes to the right of Hat Creek are the andesite of Hat Mountain (unit ah, ~40–50 ka), part of the younger Twin Lakes sequence. Photograph by Patrick Muffler.
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