Newberry Volcano: Active Threat in the High Desert

Twenty miles south of Bend, buried under the high desert, is one of the largest active volcanoes in the United States. Newberry Volcano covers an area of about twelve hundred square miles when its lava flows are counted, making it the largest volcano in the entire Cascade volcanic arc. The United States Geological Survey classifies it as having a very high threat potential, meaning it is considered capable of a significant eruption in the future, even though it has been quiet for thirteen hundred years.

That is not a long time in volcanic terms. The most recent eruption inside Newberry's summit caldera produced the Big Obsidian Flow, a field of glassy black volcanic rock that covers several square miles on the caldera floor. It formed thirteen hundred years ago, and Native peoples had quarried obsidian from the caldera for thousands of years.

The volcano is a broad shield shape, low and wide rather than a steep cone, with a caldera at the summit containing two lakes, Paulina Lake and East Lake, with hot springs between them. The entire area is protected as Newberry National Volcanic Monument. Driving south from Bend on United States Highway Ninety Seven, you cross lava flows from Newberry that erupted within the last few thousand years.

The High Desert around Bend is not ancient quiet country. The rock under your feet is geologically very young, and the volcano that made much of it is still classified by federal geologists as an active and potentially dangerous system.