How much of the Earth is volcanic?
More than 80 percent of the Earth's surface -- above and below sea level -- is of volcanic origin. Gaseous emissions from volcanic vents over hundreds of millions of years formed the Earth's earliest oceans and atmosphere, which supplied the ingredients vital to evolve and sustain life. Over geologic eons, countless volcanic eruptions have produced mountains, plateaus, and plains, which subsequently eroded and weathered into majestic landscapes and formed fertile soils.
Vertical columns of basaltic volcanic rock at Devils Postpile National Monument are formed when a think lava flows slowly cools. The vertical columns are a reflection of stress and shrinkage of the rock as it cools.
Footprints made in muddy ash during Kilauea's 1790 eruption are reminders that people experienced the largest explosive eruption in Hawai‘i in 1,000 years. More than 80, and possibly several hundred, people were killed by the eruption soon after the footprints were made.
An HVO geologist shields his face from the intense heat as he takes a sample of active lava on the Kahaualeʻa 2 flow, Kilauea Volcano Hawaii. The chemistry of the lava is analyzed through time and used to study changes in the magmatic system.
Some of the thick volcanic deposits at Okmok that are being studied to reconstruct the sequence of events during the 2008 eruption. Photo taken on August 6, 2010 by Dr. Ort.
Trunks of forest trees, initially growing on a terrace above the Sandy River (Oregon) at Oxbow Regional Park, were buried by rapid deposition of sediment following a dome-building eruption at Mount Hood in 1781. Erosion during a flood about a week before the photo was taken exposed this "ghost forest".
In the photo is Dan Daly, a naturalist interpreter with Metro...
Two prominent, historic lava flows are visible in this aerial photo of West Hawai‘i. Kīholo Bay is flanked by the 1859 Mauna Loa flow (left) and a Hualālai flow that erupted around 1800 or earlier (right). These lava flows and other volcanic landscapes along Highways 11 and 190 will be the focus of a Volcano Awareness Month talk in Kona on Jan. 22
USGS Hawaiian Volcano Observatory scientists monitor Mauna Loa, the largest active volcano on Earth. In this 1985 aerial photo, Mauna Loa looms above Kīlauea Volcano’s summit caldera (left center) and nearly obscures Hualālai in the far distance (upper right).