VHP Photo Glossary: Effusive Eruptions
Photograph by R.W. Decker on 25 March
Mauna Loa Volcano, Hawai`i.
Lava erupts from a fissure high on the northeast rift zone of
Mauna Loa (about 3400 m) on the morning of March 25, 1984.
Fountains are 10 to 50 m high along the fissure, and lava output
is estimated at 1-2 million m3
/hour. This fissure
fed a narrow `a`a lava flow that moved only about 5 km downslope
(lower right) before new vents became active farther downrift. See
from the USGS Hawaiian Volcano Observatory for more information
and images about the 1984 eruption of Mauna Loa.
Photograph by Juan Carlos Gavilanes
on 3 December 1998; Universidad de Colima
Colima Volcano, Mexico.
A stubby andesite lava flow advances 900-1,200 m down the southwest
side of Colima Volcano. Lava was first observed in the summit crater
on November 20 and began spilling over the crater rim the next day.
Colima Volcano is the most historically active volcano in Mexico.
For more information about Colima, see the volcanic
activity reports provided by the Smithsonian Institution's Global
Photograph by S.R. Brantley on 29
Obsidian flow, Long Valley Caldera, California.
Viscous rhyolite lava was erupted to form several circular-shaped
lava flows, often referred to as domes, following a series of
explosive eruptions from the Mono-Inyo Volcanic Chain. The eruptions
occurred about 550-650 years ago. Obsidian flow (foreground) is
about 1.5 km wide (left to right). A smaller lava dome, Wilson
Butte, was erupted about 1,400 years ago (left of Obsidian flow),
also following a series of explosive eruptions.
Related photo glossary terms: