Within the ash plumes of explosive volcanic eruptions, collisions among countless pyroclastic particles sometimes lead to the buildup of static charges that discharge dramatically as volcanic lightning. In a new study, researchers have found that this lightning can, in turn, melt and fuse ash particles into distinctive glassy grains called spherules. Identifying and studying these spherules could help scientists better understand past and future eruptions, the study’s authors suggest. Read more
Volcanic lightning turns ash into glass
Cortney Science & Technology + ash, earth magazine, eruptions, geology, volcanoes
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Underwater volcano might be erupting off of Oregon coast
Cortney Science & Technology + eruptions, geology, volcanoes
Almost every day for the last five months, hundreds of small earthquakes have rattled Axial Seamount, an underwater volcano located three hundred miles off of the Oregon coast. At the same time, underwater pressure sensors have revealed that the surrounding seafloor had been slowly rising. Then, on April 24, almost eight thousand earthquakes rumbled Axial and the seafloor dropped almost eight feet! Read more →
Mount Sinabung, Indonesia October 2014 eruptions
Cortney Science & Technology + indonesia, pyroclastic flows, tectonics, volcanoes
Mount Sinabung—a 2,460-meter-high Indonesian stratovolcano which has erupted in 2010, 2013, and early 2014—kicked off October with ongoing magnificent eruptions, extruding viscous intermediate lava lobes which collapsed, sending break-neck speed pyroclastic flows as far as 3.5-4 km. Compare this Pelean eruption to last month's devastating phreatic eruption in Japan, another island arc. Read more →
Mount Ontake: phreatic eruption in September 2014 kills 30+ hikers
Cortney EMS, Health & Medicine, Science & Technology + japan, volcanoes
Mount Ontake—Mount Fuji's lesser known cousin, a 3,000 meter tall stratovolcano in central Japan—erupted at noon on September 27, giving just 12 minutes of notice in the form of tremors. Read more →
Volcano news: how slopes affect lava flows, challenge to traditional volcano model, Mauna Loa waking up
Cortney Science & Technology + geology, hawaii, lava flows, rift zones, volcanoes, yellowstone
The summer of 2014 has been an exciting one for volcano science!
Easy Science: The Great Oxygenation Event
Cortney Science & Technology + ancient earth, archean, atmosphere, Easy Science, geology, precambrian, volcanoes
The Earth wasn't always a friendly place to live. Not only was it covered in lava and constantly eruption, its atmosphere was chocked with volcanic gases like carbon dioxide and sulfur dioxide. How and when did the atmosphere reach its current oxygen-rich state? This post will walk through the processes as well as some of the evidence that allows us to understand what happened. While I describe as a series of apparently discrete steps, it's important to remember that these processes sometimes overlapped and that they occurred over a span of time, often millions or billions of years.
Hawaiian volcano rift zones
Cortney Science & Technology + fissures, geology, hawaii, rift zones, volcanoes
In Hawaii, volcanoes form over a hot spot, an area where magma rises from the mantle and breaks through the crust. The Pacific plate moves northwest over the hot spot—which remains stationary—eventually carrying the old volcano away from the hotspot. A new volcano then begins to form, with repeated basaltic eruptions building a broad shield volcano. Read more →
Types of volcanic eruptions and their dynamics
Cortney Science & Technology + Easy Science, eruptions, geology, igneous, volcanoes
This post will focus on the processes driving volcanic eruptions (for more details on all things volcano, visit this awesome site by SDSU). The most important factor controlling eruption type is the composition of the lava, which controls how much gas the lava contains. The more viscous the lava, the more gas it traps—and the more gas, the more explosive the eruption.
Types of volcanic rocks, lava, and deposits
Cortney Science & Technology + density currents, Easy Science, geology, igneous, pyroclastic flows, volcanoes
Volcanic rocks are extrusive igneous rocks. There are two main groups: rocks that form from the solidification of lava flows (extrusive), and rocks that form from the compaction of solid volcanic fragments (pyroclastic). This post will cover the basics in easy-to-grasp bullet-point style that facilitates comparison between volcanic rocks. For information on eruption types, click here.
Yellowstone volcanism: the three big eruptions
Cortney Science & Technology + geology, igneous, volcanoes, yellowstone
The Yellowstone Supervolcano, fed by a continental hotspot, has erupted many times over its 70 million year history, but three eruptions blanked the continent. Today, the sponge-like upper magma chamber is 80 km by 20 km, or 4,000 km3 by volume, of which 8% is molten; another deeper and larger magma reservoir, 46,000 km3 by volume, of which 2% is molten, lays 65 km beneath the ground. Despite its deceptive beauty, Yellowstone is an active volcano (perhaps most obviously evidenced by its frequent earthquakes) that will violently erupt at some point in the future. Read more →