Volcanic action has shaped the land and ocean of the Pacific Northwest for millions of years. The fascinating land forms that remain tell the story of that history that continues to shape the land today.
A relatively recent volcanic eruption in the 17th century created this Cinder Cone in Lassen Volcanic National Park. At 700 feet high, it is quite a leg burner of a climb on a sunny afternoon. It is made of loose scovia, which is formed when blobs of lava cool off in flight.
The crater, which is obscured from the bottom of the cone, comes into full view from the top rim. There are actually two rims, about 1,050 feet wide and 590 feet wide.
Even in the volcanic rock, flowers are blooming. This appears to be a marumleaf buckwheat about to bloom.
Going back much further in time, the volcanic activity of the ancient Mount Tahema in Lassen National Park stretches back millions of years. The volcanic heat that rages below the surface is evident in the boiling waters and steam vents at Bumpass Hell. Sulfate metals that remain after the water evaporates leave yellow and brassy color traces on the earth’s crust.
Traveling northward into Oregon in the Central Cascades, another relatively recent volcanic explosion has left 65 square miles of basaltic black volcanic rock. It erupted from Yapoah Cone about 2,600 years ago, overlapping another earlier flow from Belknap Crater. The Dee Wright Observatory was constructed from the volcanic rock by the Civilian Conservation Corps during the Great Depression.
The Obsidian Trail in the Central Cascades of Oregon winds through lava beds with the Three Sisters Mountain Range in the distance. An eruption from Middle Sister about 38,000 years ago produced the rhyolite rock of the Obsidian Cliffs.
Just upstream from Obsidian Falls, along the Pacific Crest Trail, a refreshing spring cuts through the rocky slopes.
On the Oregon Coast, the Pacific Ocean washes over remnants of volcanic flows from millions of years ago. Shifts in tectonic plates caused magma flows that popped up through fissures to create basaltic rock forms. Similar rock forms are found throughout the Oregon Coast.