NeMO Home NeMO Explorer image background banner image of tubeworms NOAA Home spacer
spacer image
spacer image
spacer image
Explorer Home Virtual Sites Concepts Multimedia Help spacer
spacer image
spacer image
spacer image
Axial Volcano
Axial Volcano location map

The Juan de Fuca Ridge is a small portion of the world-wide mid-ocean ridge system that happens to lie within 300 miles of the coast of the northwest U.S. Here the seafloor spreads at about 6 cm per year. In the past 15 years, three separate volcanic eruptions have been detected in the NE Pacific by a formerly top-secret U. S. Navy system originally designed to detect and track submarines. The most recent eruption occurred in 1998 on the summit of a large seamount called Axial Volcano. Axial rises almost a kilometer above the rest of the ridge, and is unusually shallow because it has a high magma supply relative to the rest of the ridge. Axial is the latest in a series of large volcanoes built by the passage of the earth’s crust over a deeper "hot-spot" (the Cobb-Eikelberg hotspot) in the mantle, which is the source of the extra magma supply. In a sense, Axial is a hybrid feature, created where a hot-spot intersects a mid-ocean ridge.

The caldera of Axial was formed in the recent geologic past by subsidence after withdrawal of magma from beneath the summit of the volcano. The shape of the caldera is somewhat rectangular and it lies between two rift zones of the volcano. The caldera is defined on three sides by a boundary fault with up to 100 m of relief. The caldera opens toward the south, where the 1998 lava flow erupted along the south rift zone.
spacer image
horizontal bar
spacer image

Related panoramas:
Axial Seamount in QTVR | Axial caldera in QTVR

Other NeMO-related concepts:
Mid-ocean ridges | seafloor spreading | seamounts & hot spots | calderas | Axial volcano
Hydrothermal vents | fluid paths | focused vents | diffuse vents | sulfide | anhydrite
Animal Gallery | chemosynthesis | biological colonization of new lava

Lava morphology | sheets | pillows | lava contacts | skylights | pillars | the 1998 flow
NeMO at Axial | the 1998 eruption | the rumbleometer story | lava flow animation

spacer image
horizontal bar
spacer image
NeMO Home |About NeMO | Expeditions | NeMO Net | Explore | Dive! | Education
spacer
horizontal bar
spacer
spacer imagePrivacy Policy | Disclaimer | nemo.webmaster@noaa.gov