[Turtle]

We start with one eruption, and then build from there. What do we know about underwater volcanoes, and what do we not? ........

Underwater - Submarine Volcanoes

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May 20, 2000 - Reuters
In the Pacific Ocean there are ocean basins - volcanoes, of which there are estimated to be about 20,000 on the ocean bottoms of the world. Some of these form single mountains, and others join with other volcanoes to form ridges. The highest ones rise above the surface of the water as islands, which in many cases linear groups such as the Hawaiian Islands.
...
Marine geologists have reported that a newly discovered undersea volcano east of Samoa is erupting, sending out a five-mile cloud of "smoggy" water from its summit.

Local students recently named the volcano, located 28 miles east of Taiu Island, 'Vailulu'u'. The volcano rises up more than 16,400 feet from the seabed to within 2,000 feet of the ocean's surface.

Scientists from Scripps Institution of Oceanography and the Woods Hole Oceanographic Institution first mapped the volcano during a research cruise in 1999. They returned this spring to find the volcano erupting. Anthony Koppers, a scientist at Scripps who studies undersea volcanoes, said the find was exciting because so few of the world's undersea volcanoes are accessible to study. He said, "We have access to the buildup of a volcano that will eventually become an island."

[Turtle]

Staying with Vailulu'u undersea volcano:.......................

Global Volcanism Program | Vailulu'u | Summary

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On July 10, 1973, explosions from Vailulu'u were recorded by SOFAR (hydrophone records of underwater acoustic signals). An earthquake swarm in 1995 may have been related to an eruption from the seamount. Turbid water above the summit shows evidence of ongoing hydrothermal plume activity. ...

[Turtle]

A bit more with Vailulu'u undersea volcano: a moat of death, only a volcano Mother could love. .......................

Giant Deep-Sea Volcano With "Moat of Death" Found

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Moat of Death

The moat lies between Vailulu'u's encircling crater and the rim of the cone inside it.

It's an extremely toxic environment, Staudigel said, where oxygen levels are dangerously low and volcanic vents fill the water with iron soot "almost like underwater smog."

The volcano is also spewing liquid carbon dioxide, which combines with seawater to make a deadly acidic mix. ...

[freeztar]

Hmmm...iron soot eh? No mention of H2....hmmmm...

[Turtle]

freeztar said:

Hmmm...iron soot eh? No mention of H2....hmmmm...

Sorry if my chemistry is a little oxidized; please bear with me. There is plenty o' H down on the volcano, but as far as I've found it is not there as a free gas. I have to check some more to see what rocks may have it, but there is a lot tied up with sulphur as hydrogen-sulphide which the colonies of bacteria feed on.

Without regard to any specific links, undersea volcanoes aren't our Mommies' terestrial type I am finding. Hydration to who laid the chunk, enormous pressure, sodium, complex interconnected biotic systems, high temperature variances, and the physical structure of erupted lava, to name a few differences I have found so far.

[Turtle]

agu.org said:

... The outflow water was typically warmer by 0.1-0.2 C; the maximum temperature range was 0.6 C, about half of that observed at the NW breach. A 12-hour continuous profiling CTD-LBSS station was serendipitously sited on top of a large diffuse-venting hydrothermal field, in the crater moat just north of the new volcanic cone. The water column here was incredibly dynamic, with a 5-10m bottom boundary layer, 1 C above ambient, forming by diffuse flow from the basalt substrate in a matter of minutes; this layer would destabilize, detach, and rise with velocities of ~ 1 cm/sec. This buoyant water was both warmer and less saline than either the ambient crater water, or the cold outside water which occasionally cascaded onto this site from the nearby NW breach; it was also laden with particulates, with LBSS readings up to 1.7 NTU. Water chemistry and He isotope analyses are in progress. ...

This bit above is still on Vailulu'u volcano, or actually the new 300 meter high volcanic cone, named Nafanua formed in its crater. The quote is from an abstract down this page; try not to get lost on the other underwater volcano info you pass on the way. ................ Seamount Hydrothermal Systems: Volcanology, Biology, Geochemistry, and Oceanography II Posters - Volcanology, Geochemistry, Petrology [V]

[Turtle]

freeztar said:

Hmmm...iron soot eh? No mention of H2....hmmmm...

Just to revisit this for my clarification. When you say "H2", do you mean 'molecular' ('free'?) hydrogen as opposed to hydrogen compounds?

In the mean time, here's some more juicy bits on Vailulu'u: >>

UCSD Science & Engineering

ucsdnews said:

The timing of Vailulu’u’s volcanic activity is close to events that have been recorded by global seismic networks. Major earthquake activity was recorded at or near Vailulu’u in July 1973 and January 1995. The authors say it is quite possible that these two seismic swarms were related to the eruptions that produced their dated rock samples.

Using isotopic tracing techniques, the scientists determined that the volcano was formed by partial melting of materials in the earth’s mantle with a characteristically "Samoan" composition or pedigree. The examinations suggested volcanic activity within the past 5 to 50 years, further evidence that Vailulu’u is the current location of the Samoan hot spot.

As an interesting sidelight, the evidence for volcanic activity at Vailulu’u may have an historical antecedent in Samoan mythology. Kanaloa, the oldest Polynesian volcano god, is said to have been involved in a violent battle to the East of Ta’u after which he landed on its eastern slopes. The site of his landing was honored with a temple to Kanaloa, built about 3,000 years ago. This temple faces the site of Kanaloa’s battle, and current location of Vailulu’u. Perhaps the ancient Polynesians knew about Vailulu’u all along? ...

Post Script: I simply can't not move on to some other underwater volcanoes of interest.



New Underwater Volcano Found, Discovered Off Coast Of Antarctica 900 Feet Down - CBS News

AP said:

WASHINGTON, May 20, 2004
(AP) A previously unknown underwater volcano has been discovered off the coast of Antarctica, the National Science Foundation said Thursday.

The finding helps explain mariners' historical reports of discolored water in the area, the agency said. Material from underwater volcanoes is known to cause discoloration in water over them.
...
Highly sensitive temperature probes moving continuously across the bottom of the volcano showed signs of geothermal heating of seawater, according to the agency.

Domack said the volcano stands 2,300 feet above the seafloor and extends to within roughly 900 feet of the ocean surface.

The volcano is in an area known as Antarctic Sound, at the northernmost tip of Antarctica. There is no previous scientific record of active volcanoes in the region where the new peak was discovered. The volcano is located on the continental shelf, in the vicinity of a deep trough carved out by glaciers passing across the seafloor.

[freeztar]

Turtle said:

Just to revisit this for my clarification. When you say "H2", do you mean 'molecular' ('free'?) hydrogen as opposed to hydrogen compounds?

Yes, "free", unbonded hydrogen. I realize that methane and h20 is vented.
It was meant as a sarcastic comment directed towards another thread (of which I'm sure you're aware of the referenced thread).

[Turtle]

freeztar said:

Yes, "free", unbonded hydrogen. I realize that methane and h20 is vented.
It was meant as a sarcastic comment directed towards another thread (of which I'm sure you're aware of the referenced thread).

Roger. Moving back briefly to the liquid CO2 that Vailulu’u is putting out:

Quote

The volcano is also spewing liquid carbon dioxide, which combines with seawater to make a deadly acidic mix.

I gather from this that no molecular CO2 is getting to the atmosphere? What acids does it make, do you know?

Keep looking down.

[freeztar]

Turtle said:

I gather from this that no molecular CO2 is getting to the atmosphere? What acids does it make, do you know?

I'm sure that some of it escapes the ocean, but it would be nice to quantify it.
Carbonic acid is the acid produced, but it seems quite unstable.

wiki said:

It has since been shown, by theoretical calculations, that the presence of even a single molecule of water causes carbonic acid to revert to carbon dioxide and water fairly quickly. Pure carbonic acid is predicted to be stable in the gas phase, in the absence of water, with a calculated half-life of 180,000 years.

I just found this tasty morsel. Does under-ice count as under-water?
Press Release - First evidence of under-ice volcanic eruption in Antarctica - British Antarctic Survey

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“This eruption occurred close to Pine Island Glacier on the West Antarctic Ice Sheet. The flow of this glacier towards the coast has speeded up in recent decades and it may be possible that heat from the volcano has caused some of that acceleration. However, it cannot explain the more widespread thinning of West Antarctic glaciers that together are contributing nearly 0.2mm per year to sea-level rise. This wider change most probably has its origin in warming ocean waters.”

[InfiniteNow]

Turtle said:

AGiant Deep-Sea Volcano With "Moat of Death" Found

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The volcano is also spewing liquid carbon dioxide, which combines with seawater to make a deadly acidic mix.

This particular quote causes me further concern, as the ocean's ability to absorb CO₂ from the atmosphere is already decreasing due to saturation.

If CO₂ is ALSO entering the ocean from underwater volcanoes, that implies that the oceans will become saturated sooner, and hence will absorb far less atmospheric CO₂ than needs absorbing. It seems that nature's ability to mitigate anthropogenic contributions of CO₂won't be enough to lend much aid during the time scales pertinent to human life.




Southern Ocean Carbon Sink Weakened

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Scientists have observed the first evidence that the Southern Ocean’s ability to absorb the major greenhouse gas, carbon dioxide, has weakened by about 15 per cent per decade since 1981.

In research published in Science, an international research team – including CSIRO’s Dr Ray Langenfelds – concludes that the Southern Ocean carbon dioxide sink has weakened over the past 25 years and will be less efficient in the future. Such weakening of one of the Earth’s major carbon dioxide sinks will lead to higher levels of atmospheric carbon dioxide in the long-term.

[Turtle]

freeztar said:

I'm sure that some of it escapes the ocean, but it would be nice to quantify it.
Carbonic acid is the acid produced, but it seems quite unstable.



I just found this tasty morsel. Does under-ice count as under-water?
Press Release - First evidence of under-ice volcanic eruption in Antarctica - British Antarctic Survey

Quote

“This eruption occurred close to Pine Island Glacier on the West Antarctic Ice Sheet. The flow of this glacier towards the coast has speeded up in recent decades and it may be possible that heat from the volcano has caused some of that acceleration. However, it cannot explain the more widespread thinning of West Antarctic glaciers that together are contributing nearly 0.2mm per year to sea-level rise. This wider change most probably has its origin in warming ocean waters.”

Nice!! But.... the title misleads I think, as the article I just posted on an underwater Antarctic volcano is from 2004, so clearly this is not the first in Antarctica. I think the article clarifies that it the first in West Antarctica, wheras the one I cited is at the Northern tip.

You know what they say; where there's smoke, there's fire. I'll sharpen my axe. _________________

[Turtle]

Turtle said:

... try not to get lost on the other underwater volcano info you pass on the way. ................ Seamount Hydrothermal Systems: Volcanology, Biology, Geochemistry, and Oceanography II Posters - Volcanology, Geochemistry, Petrology [V]

Lost? Which way is up? Erhm....down? From one of the Abstracts I recommended not getting lost on at the above link: (it is the 10th in the list.) ___ ... .. ._______ __.

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Recent investigations of volcanic arcs have revealed unusually high fluxes of CO2 from several submarine arc volcanoes. In 2004 the ROPOS ROV was used to map and sample ~10 active volcanoes along the Mariana arc, and in 2005 a similar study of volcanoes along the Kermadec arc was conducted using the HURL Pisces submersible. Of particular interest are 3 volcanoes that, in addition to discharging hot vent fluid, were found to be venting a separate CO2-rich phase in the form of gas bubbles or, in one case, droplets of liquid CO2. The Champagne hydrothermal site situated at ~1600-m depth near the summit of NW Eifuku volcano (21.49°N, 144.04°E) in the northern Mariana Arc, was discovered in 2004 during NOAAs Submarine Ring of Fire (SROF) project. This unusual site was discharging two distinct fluids from the same vent field: a 103°C gas-rich hydrothermal fluid, and cold (4°C) droplets of liquid CO2. ...

[Turtle]

freeztar said:

I'm sure that some of it escapes the ocean, but it would be nice to quantify it.
Carbonic acid is the acid produced, but it seems quite unstable.

Roger the instability; I'm following the new thread on carbonic acid instability. I see one of the factors is pressure, so I found this handy water-pressure-by-depth calulator: Pressure at Water Depth Calculator

Going by these figures...

Reuters said:

Local students recently named the volcano, located 28 miles east of Taiu Island, 'Vailulu'u'. The volcano rises up more than 16,400 feet from the seabed to within 2,000 feet of the ocean's surface. ...
Underwater - Submarine Volcanoes

Water pressure at 2,000 feet = 881.7514 psi
Water pressure at 16,400 feet = 7124.5504 psi

I have sought help setting up a catalog of underwater volcanoes using GoogleEarth; Vailulu'u is on the regular volcano list, but there does not appear to be an exclusively underwater catalog.

That's a rap...erhm...wrap.

[freeztar]

Awesome Turtle!

I was wondering how to calculate psi at depth x, so that link is nice.

Let us know what the GE community comes up with.