Deep-Sea Volcanoes Don't Just Produce Lava Flows, They Also Explode

Underwater Times: Researchers: Deep-Sea Volcanoes Don't Just Produce Lava Flows, They Also Explode!

MONTREAL, Quebec -- McGill geology researchers' discovery of high concentrations of CO2 at mid-ocean ridges confirms explosive nature of certain volcanic eruptions

Between 75 and 80 per cent of all volcanic activity on Earth takes place at deep-sea, mid-ocean ridges. Most of these volcanoes produce effusive lava flows rather than explosive eruptions, both because the levels of magmatic gas (which fuel the explosions and are made up of a variety of components, including, most importantly CO2) tend to be low, and because the åvolcanoes are under a lot of pressure from the surrounding water.

Over about the last 10 years however, geologists have nevertheless speculated, based on the presence of volcanic ash in certain sites, that explosive eruptions can also occur in deep-sea volcanoes.

But no one has been able to prove it until now.

By using an ion microprobe, Christoph Helo, a PhD student in McGill's Department of Earth and Planetary Sciences, has now discovered very high concentrations of CO2 in droplets of magma trapped within crystals recovered from volcanic ash deposits on Axial Volcano on the Juan de Fuca Ridge, off the coast of Oregon.

These entrapped droplets represent the state of the magma prior to eruption. As a result, Helo and fellow researchers from McGill, the Monterey Bay Aquarium Research Institute, and the Woods Hole Oceanographic Institution, have been able to prove that explosive eruptions can indeed occur in deep-sea volcanoes. Their work also shows that the release of CO2 from the deeper mantle to the Earth's atmosphere, at least in certain parts of mid-ocean ridges, is much higher than had previously been imagined.

Given that mid-ocean ridges constitute the largest volcanic system on Earth, this discovery has important implications for the global carbon cycle which have yet to be explored.

Another Volcano Glossary - the As

Aa - Hawaiian word used to describe a lava flow whose surface is broken into angular, jagged fragments.

Agglutinate - A volcanic deposit formed by the accumulation of flattened and welded fragments, typically derived from showers of still-molten rock particles ejected in magma fountains. The liquid fragments may accumulate to form a stream of lava.

Andesite - A lava of intermediate composition, usually light gray or brown in color. Andesite has a silica content ranging from about 54 to 62 percent.

Andesite line - An imaginary line drawn around the boundary of the Pacific Ocean basin, seperating continental and oceanic lava rocks according to their chemical composition. On the Pacific side of the line lavas are basaltic. On the continental side, lavas with a higher silica content, such as andesites, commonly occur.

Ar - the element argon

Ash - fine particles of pulverized blown from a volcano. Measuring less than about 0.1 in diamer, ash may be either solid or molten when first erupted.

By far the most common variety is vitric ash, glassy particles formed by gas bubbles bursting through liquid magma.
Lithic ash is formed of older rock pulverized during an explosive eruption, while in:
crystal ash each grain is composed of a single crystal or group of crystals with only traces of glass adhering to them. Many volcanic ash deposits contain mixtures of all three kinds in various proportions.

Ash fall -a rain of ash from an eruption cloud

Ash flow - An avalanche of hot volcanic ash and gases that can travel great distances at high speeds from an erupting vent. Large-volume ash flow deposits commonly solidify to form Ignimbrites. (Also called a pyroclastic flow).

Asthenosphere - A zone of the earth's outer shell beneath the lithosphere. Of undetermined thickness, this is a region of weakness where plastic movements occur.



Bibliography
Fire Mountains of the West: The Cascade and Mono Lake Volcanoes, Stephen L. Harris. Mountain Press Publishing Company. 1988

Volcano-sparked fire threatens Hawaii wildlife area

CNN: Volcano-sparked fire threatens Hawaii wildlife area

A fire ignited by lava from the Kilauea Volcano on Hawaii's Big Island is threatening what a National Park Service spokesman calls "a living laboratory of Hawaiian plants and animals," the Star-Advertiser in Honolulu reports.

The fire, which began on March 5, has burned 100 acres of a 2,750-acre special ecological area in a lowland rain forest, according to the Park Service.

Among the creatures in the area are happy face spiders, carnivorous caterpillars and the endangered Hawaiian bat, the newspaper said, citing Park Service fire information spokesman Gary Wuchner.

"It best represents what Hawaii was, and is a seed source for plants and refuge for birds," Hawaii Volcanoes National Park spokeswoman Mardi Lane told the Star-Advertiser.

Forty Park Service firefighters from Hawaii and western mainland states are battling the fire, according to the report.

Rain aids battle against 1,800-acre volcano blaze

Star Advertiser (Honolulu): Rain aids battle against 1,800-acre volcano blaze
Hawaii Volcanoes National Park firefighters continue to map and monitor the Napau Fire located on the east rift of Kilauea Volcano, which has burned more than 1,800 acres since it was first triggered by the March 5 Kamoa­moa fissure eruption.

Two days of rain have helped to slow the fire's spread, and fire crews have used the time to develop safety zones in cool areas within the fire perimeter and monitor vegetation that can act as fuel for the blaze.

According to Napau Fire information officer Gary Wuscher, pockets of high heat remain on the front and flanks of the fire.

Wuscher has said that park firefighters are waiting for more favorable conditions before engaging the fire for safety and practicality considerations.

In the meantime, crews have been busy with various precautionary and strategic tasks.

Off Chain of Craters Road near the Pali, crews installed a temporary water storage tank, which will allow firefighters to draw water continuously without having to move their fire engine back and forth.

Crews were also able to cut back brush to protect sensitive monitoring equipment used by the U.S. Geological Survey to track seismic activity.

Volcanoes' role in origins of life found after 50 years lost in a lab

The Independent (UK): Volcanoes' role in origins of life found after 50 years lost in a lab
An experiment carried out more than 50 years ago has revealed that volcanoes may have played a crucial role in the formation of the first organic building blocks of life, which led to the first replicating lifeforms on earth about 4.5 billion years ago.


Laboratory samples left over from a 1958 experiment in an American university have revealed, with the help of modern analytical techniques, that scientists had unwittingly discovered that gases given off by volcanoes can be used to make the vital sulphur-containing amino acids of proteins. The discovery is further vindication of the pioneering experiments of Stanley Miller, who as a young graduate student demonstrated that a "primordial soup" of water and a few simple gases such as ammonia and hydrogen can, with the help of electricity discharges to simulate lightning, produce the more complex organic molecules of life.

Dr Miller, who died in 2007, conducted many of his experiments at the University of California, San Diego, and received worldwide recognition for his earliest work in 1953.

But there was one set of experiments carried out five years later with the volcanic gas, hydrogen sulphide, that he seemed to have put to one side without fully realising what he had found. Jeffrey Bada, a former student of Dr Miller's who is now a Professor of Marine Chemistry at Scripps Institution of Oceanography in San Diego, discovered the residue samples from the original 1958 experiment and analysed the contents using highly sensitive chemical techniques that were not available 50 years ago. The study, published in the journal Proceedings of the National Academy of Sciences, revealed that Dr Miller was the first scientist to synthesise important sulphur-containing amino acids in this simulation of the environment of early earth. In total, Professor Bada's team found 23 amino acids and four similar compounds known as amines in Dr Miller's discarded samples, including seven substances containing sulphur.

"This experiment marks the first synthesis of sulphur amino acids from spark-discharge experiments designed to imitate primordial environments. The relative yield of some amino acids... are the highest ever found in a spark-discharge experiment," the scientists write. Professor Bada said that Dr Miller's team was only able to use a relatively primitive technique called paper chromatography to detect the presence of organic molecules.

The creation of sulphur-containing amino acids using similar techniques was eventually confirmed in the 1970s, including in Dr Miller's lab. "Unbeknownst to him, he'd already done it in 1958," Professor Bada said.

Shinmoedake volcano: Japan's explosive geology explained

Volcanic lightning or a dirty thunderstorm is seen above Shinmoedake peak as it erupts on January 28. The volcano erupted again on Sunday, with the largest blast in more than half a century.

Christian Science Monitor: Shinmoedake volcano: Japan's explosive geology explained

When it comes to building a country, you'd be hard-pressed to do it in a more volatile part of the world than Japan.

About 1,500 earthquakes strike the island nation every year. Minor tremors occur on a nearly daily basis. Deadly quakes are a tragic part of the nation's past.

The anniversary of the Great Kanto Earthquake of 1923, for example, which killed more than 100,000 people around Tokyo, is now national Disaster Prevention Day. More recently, a 6.8 magnitude earthquake struck the city of Kobe in 1995, killing more than 6,000 people.

Japan has such a large potential for earthquakes — and disaster — because the nation sits atop four huge slabs of the Earth's crust, called tectonic plates. These plates mash and grind together and trigger deadly earthquakes, like the 8.9-magnitude quake that struck on Friday (March 11). [Photos: Japan Earthquake and Tsunami in Pictures]

The tectonic activity has also created explosive volcanoes, like south Japan's Mount Kirishima, which continued its recent eruptive streak today (March 14).

Japan lies along the Pacific Ring of Fire — a narrow zone around the Pacific Ocean where a large chunk of Earth's earthquakes and volcanic eruptions occur. Roughly 90 percent of all the world's earthquakes — and 80 percent of the largest ones — strike along the Ring of Fire.

Great quake
Friday's quake off the east coast of Honshu, Japan's largest island, was the fifth-largest ever recorded, according to the U.S. Geological Survey (USGS), and the largest ever recorded in Japan.

More than 150 aftershocks of magnitude 5 or greater have followed — including more than two dozen of magnitude 6 or greater. The number of aftershocks in Japan is not uncommon for an earthquake of this size, said geologist Eric Geist, of the USGS, at a news conference last week, and the rumbling could last for a year or more.

As a rule of thumb, an earthquake's largest aftershock is about one magnitude lower than the mainshock, said Paul Caruso, a geophysicist with the USGS. The largest aftershock from this earthquake has been a magnitude 7.1.

Japan's tectonic shuffle
Earthquakes typically occur along faults, which are breaks in the rocky plates of the Earth's crust. These faults accumulate strain over the years as two plates butt heads.

Japan's stretch of the Ring of Fire is where the North American, Pacific, Eurasian and Philippine plates come together. Northern Japan is largely on top of the western tip of the North American plate. Southern Japan sits mostly above the Eurasian plate.

Friday's temblor struck 231 miles (373 kilometers) northeast of Tokyo and 80 miles (130 km) east of Sendai, Honshu, in the Pacific Ocean near the Japan Trench. The Japan Trench, a subduction zone, is where the Pacific plate — beneath the Pacific Ocean — dives underneath North American plate — beneath Japan. This violent movement, called thrust faulting, forced the North American plate upward in this latest quake.

On average, the Pacific Plate is moving west at about 3.5 inches (8.9 centimeters) per year, and the movement has produced major earthquakes in the past — nine earthquakes of magnitude 7 or greater since 1973. The largest of these was a magnitude 7.8 earthquake in December 1994, which caused three fatalities and almost 700 injuries, approximately 160 miles (260 km) to the north of Friday's quake. In June of 1978, a magnitude 7.7 earthquake about 22 miles (35 km) to the southwest caused 22 fatalities and over 400 injuries.

Earthquake aftermath
The rupture during Friday's quake was almost 200 miles (322 km) long, on an underwater fault that is about 220 miles (354 km) long by about 60 miles (97 km) wide, said Tom Broker, of the USGS. Earthquakes along that fault can affect the rest of the world — literally.

"This is just a ginormous earthquake," Broker said. "It's really hard to grasp how big it is."

For one, the intense temblor accelerated Earth's spin, shortening the length of the 24-hour day by 1.8 microseconds, according to geophysicist Richard Gross at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

Japan's Earthquake Research Committee said the earthquake forced the North American plate eastward by about 66 feet (20 meters), reported Japan's national broadcast agency, NHK. The entire island of Honshu was moved about 8 feet (2.4 m) east, according to USGS scientists. Geologists in St. Louis reported that their city moved up and down a fraction of an inch during the quake, but too slowly for anyone to notice, reported the St. Louis Post-Dispatch.

Tsunami trigger
Friday's huge earthquake was about 15.2 miles (24.4 km) deep, which was shallow enough to trigger a tsunami as the seafloor was pushed up and away from Japan. As the energy from the quake rose, two waves were created. Wave heights of more than 20 feet (6 m) socked Japan's coast, where the death toll is expected to exceed 10,000, according to news reports.

At the same time, a tsunami roared across the Pacific Ocean at the ground-speed of an airplane, said Ken Hudnut of the USGS. Damage was reported in Hawaii and near the California-Oregon border.

Explosive eruptions
Colliding tectonic plates not only trigger earthquakes — they also build volcanoes. About 10 percent of the world's active volcanoes are in Japan, mostly where the Pacific Plate is diving below the Philippine Plate.

About 950 miles (1,500 km) south of Friday's earthquake, the Shinmoedake cone on the Kirishima mountain range erupted on Sunday. The blast was the volcano's largest in 52 years, the BBC reported. The volcano had been active earlier in the year, and despite the renewed activity coinciding with last week's earthquake, any link between the two would be speculation at this time, reported the Los Angeles Times.

The Pacific Ring of Fire is home to 452 volcanoes in total — that's 75 percent of the world's active and dormant volcanoes.

Mud volcano erupts in Azerbaijan

en.tren.az: Mud volcano erupts in Azerbaijan
A mud volcano erupted in the Gobustan region due to aftershocks, Geology Institute Mud Volcanoes Department Director Adil Aliyev told Trend.

He added that tremors were systematically recorded in the area.

"The institute is researching Shikhzeyirli and other mud volcanoes," Aliyev said.

The Shikhzeyirli mud volcano outside the Shikhzeyirli village in the Gobustan region erupted on March 13. A large mud-bath occurred on the surrounding area as a result of the explosion.

During the eruption, the flame height reached 60-70 meters.