CoAxial Segment

Geography & Climate

CoAxial Segment is located in Undersea Features, within the Northeast Pacific Rifts Volcanic Province of the broader Eastern Pacific Volcanic Regions. Situated at 46.52° N, 129.58° W in the Northern Hemisphere, the volcano lies within a temperate climate zone. With an elevation of -2,400 meters — below sea level — CoAxial Segment is a submarine or submerged volcanic feature. Submarine volcanoes make up the majority of Earth's volcanic activity, though most eruptions go unobserved beneath the ocean surface. 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

CoAxial Segment 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 CoAxial Segment in Undersea Features 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

CoAxial Segment has 2 recorded eruptions in the geological database, spanning from 1986 CE to 1993 CE. These eruptions span roughly 7 years of volcanic history. The most recent eruption in 1993 CE places this volcano within the modern era of volcanological observation.

GVP Reference Summary

The CoAxial segment of the Juan de Fuca Ridge is about 435 km W of the Oregon coast, NE of Axial volcano. A submarine eruption along the CoAxial segment that produced thermal plumes and a new lava flow was detected by acoustic hydrophones in June 1993, just days after installation of the hydrophone system. This was the first deep-sea volcanic eruption detected as it was happening. The location of the eruption was at a depth of about 2,400 m, about 37 km NE of Axial volcano. Bathymetric surveys indicated that one or more additional sea-floor lava extrusions took place immediately east of the 1993 lava flow sometime between 1981-82 and 1991.

— Smithsonian Institution, Global Volcanism Program