Diamond Craters

Geography & Climate

Diamond Craters is located in United States, within the High Lava Plains Volcanic Province of the broader North America Volcanic Regions. Situated at 43.10° N, 118.75° W in the Northern Hemisphere, the volcano lies within a temperate climate zone. With a summit elevation of 1,435 meters above sea level, Diamond Craters is a moderately sized peak that remains accessible to hikers and researchers for much of the year. The volcanic landform is characterized as a cluster, which describes the physical shape and structure of the volcanic edifice as observed from the surface.

Geological Context

Diamond Craters is situated along a rift zone, where tectonic plates are pulling apart. As the crust thins and fractures, magma rises to fill the gap, creating volcanic activity. Rift volcanism typically produces more fluid lava flows rather than explosive blasts, which means communities near Diamond Craters in United States generally face slower-moving hazards like lava flows and ground fissures rather than sudden pyroclastic events. However, rift volcanoes can still generate significant ash emissions and gas releases that affect local air quality. The dominant rock type is basalt / picro-basalt, 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

Diamond Craters has 1 recorded eruption in the geological database, spanning from 5610 BCE to 5610 BCE. The most powerful recorded event was a cataclysmic eruption with ash columns reaching the stratosphere in 5610 BCE, reaching VEI 4 on the Volcanic Explosivity Index.

Significance

With a maximum recorded VEI of 4, Diamond Craters 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.

GVP Reference Summary

Diamond Craters volcanic field consists of a 70 km2 area of basaltic lava flows along with numerous cinder cones and maars located between the SE Oregon town of Burns and Steens Mountain. A basaltic pahoehoe lava field is overlain by deposits from phreatomagmatic and Strombolian eruptions that formed a late-stage central vent complex of about 20 craters and cones that densely fill a 1.1 x 1.6 km caldera. The age is constrained to within 7,320-7,790 calibrated years Before Present by radiocarbon-dated floodplain deposits below the lava flows and paloemagnetic evidence (Sherrod et al., 2012). Doming has created a series of six overlapping topographic highs. The highest of these is known as Graben Dome; its summit is cut by a NW-SE graben 0.4 x 2.1 km long and 30 m deep. Lava flows on the E side of the field, scattered cinder cones, and maars formed during the last stage of activity.

— Smithsonian Institution, Global Volcanism Program