Newberry

Geography & Climate

Newberry is located in United States, within the High Cascades Volcanic Arc of the broader North America Volcanic Regions. Situated at 43.72° N, 121.23° W in the Northern Hemisphere, the volcano lies within a temperate climate zone. At 2,434 meters above sea level, Newberry rises above the surrounding terrain into montane or subalpine conditions. The elevation creates distinct ecological zones along its flanks, from forested lower slopes to exposed rocky terrain near the summit. The volcanic landform is characterized as a shield, which describes the physical shape and structure of the volcanic edifice as observed from the surface.

Geological Context

Newberry sits in a subduction zone, where one tectonic plate dives beneath another, creating intense heat and pressure that generates magma. Subduction zones are responsible for many of the world's most explosive volcanoes and deadliest eruptions. For communities in United States near Newberry, this tectonic setting means the volcano is capable of producing powerful explosive eruptions, pyroclastic flows, and lahars that can threaten populated areas within tens of kilometers of the summit. The dominant rock type is andesite / basaltic andesite, a dark, fine-grained volcanic rock that forms from rapidly cooling, low-viscosity lava. Basaltic eruptions tend to be less explosive and produce fluid lava flows that can travel long distances. While less immediately dangerous than explosive eruptions, basaltic lava flows can destroy structures and infrastructure in their path, and volcanic gases released during these eruptions can affect air quality over a wide area.

Eruption History Summary

Newberry has 11 recorded eruptions in the geological database, spanning from 9210 BCE to 690 CE. The most powerful recorded event was a cataclysmic eruption with ash columns reaching the stratosphere in 690 CE, reaching VEI 4 on the Volcanic Explosivity Index. Notable eruptions include 690 CE (VEI 4), 490 CE (VEI 4), 5070 BCE (VEI 3). This level of eruptive frequency indicates a persistently active volcanic system that warrants ongoing monitoring.

Significance

With a maximum recorded VEI of 4, Newberry has demonstrated the capacity for significant explosive eruptions that can impact regional aviation, agriculture, and communities tens of kilometers from the summit. VEI 4 eruptions produce ash columns reaching 15-25 kilometers into the atmosphere. With 11 recorded eruptions, Newberry has a substantial eruptive history that provides valuable data for understanding volcanic behavior and assessing future hazards in the North America Volcanic Regions region.

GVP Reference Summary

Newberry volcano, situated east of the Cascade Range, covers an area of about 1,600 km2. The low-angle basaltic to basaltic andesite shield volcano includes more than 400 cinder cones, but has also produced major silicic eruptions associated with formation of a 6 x 8 km summit caldera containing two lakes. The earliest eruptive products (less than 0.73 Ma) consist of a sequence of ash-flow and airfall tuffs. Caldera collapse is thought to be associated with major ash deposits from about 0.5 and 0.3-0.5 Ma. These eruptions were preceded by the emplacement of numerous mafic cones and vents, and silicic lava domes and flows, many of which are aligned NNW and NNE parallel to regional fault zones. Six major eruptions from the early Holocene to about 1,300 years ago have included both basaltic lava flows from flank vents, the explosive ejection of rhyolitic pumice and pyroclastic flows, and the extrusion of obsidian flows within the caldera.

— Smithsonian Institution, Global Volcanism Program