More than 19,000 undersea volcanoes just discovered

[KeithMD]

These aren't likely to be a hazard in UK waters (he said hopefully). But it's mind-boggling that they were uncharted for so long!

Science | AAAS

Published this month in Earth and Space Science, the new seamount catalog is “a great step forward,” says Larry Mayer, director of the University of New Hampshire’s Center for Coastal and Ocean Mapping.

 

[AntarcticPilot]

These aren't likely to be a hazard in UK waters (he said hopefully). But it's mind-boggling that they were uncharted for so long!

Science | AAAS

Published this month in Earth and Space Science, the new seamount catalog is “a great step forward,” says Larry Mayer, director of the University of New Hampshire’s Center for Coastal and Ocean Mapping.

Unlikely to be a hazard anywhere. The minimum depth over them is ample for navigation (we'd know about them already if it wasn't), and the vast majority are dormant or extinct. Plate Tectonic theory gives us a pretty good handle on where active vulcanism is likely; these are remnants of past activity in the vast majority of cases.

 

[KeithMD]

The minimum depth over them is ample for navigation (we'd know about them already if it wasn't),

True - but they are a hazard for certain forms of navigation. There aren't many submarine drivers on YBW - or are there?

The U.S. submarine fleet’s biggest adversary lately hasn’t been Red October. In 2005, the nuclear-powered USS San Francisco collided with an underwater volcano, or seamount, at top speed, killing a crew member and injuring most aboard. It happened again in 2021 when the USS Connecticut struck a seamount in the South China Sea, damaging its sonar array.

 

[AntarcticPilot]

True - but they are a hazard for certain forms of navigation. There aren't many submarine drivers on YBW - or are there?

The U.S. submarine fleet’s biggest adversary lately hasn’t been Red October. In 2005, the nuclear-powered USS San Francisco collided with an underwater volcano, or seamount, at top speed, killing a crew member and injuring most aboard. It happened again in 2021 when the USS Connecticut struck a seamount in the South China Sea, damaging its sonar array.

There are one or two!
I suspect that the vast majority of seamounts within the diving depth of submarines were already known to the relevant bodies - if not to the wider world!
More seriously, at least low-resolution maps have been available from the inversion of radar altimeter data since the 1990s. This is good enough to allow at least "Here be Dragons" assessment of the safety or otherwise of a region for navigation at greater depth than we poor mortals confined to navigating in 2 dimensions only! I've got a vague recollection that both the incidents mentioned were in waters known to be hazardous.

 

[NormanS]

Submarines are perfectly capable of running aground without the need for volcanoes.

 

[KeithMD]

Oh yes
In our own "back yard" as well.
Nuclear submarine HMS Astute runs aground off Skye

 

[mjcoon]

IIRC one of the putative explanations of the Bermuda Triangle, as mentioned in wikipedia.org/wiki/Bermuda_Triangle was gas hydrate decomposition aerating the sea and thus reducing its density so ships sink. Same could happen with undersea volcanoes...

 

[jamie N]

A few years ago, I worked for the University of Kiel in the Tyrrhenian Sea, doing underwater survey close to Stromboli, where we watched mini volcanoes forming. Very small items, that soon sealed themselves up, but were a hazard to safe ROV ops through snagging. Nothing on the scale of the Nuclear Subs though.
As an aside, on the USS San Francisco, wasn't it the case that the vessel was using a raster chart rather than a vector chart; as simple as that?

 

[AntarcticPilot]

IIRC one of the putative explanations of the Bermuda Triangle, as mentioned in wikipedia.org/wiki/Bermuda_Triangle was gas hydrate decomposition aerating the sea and thus reducing its density so ships sink. Same could happen with undersea volcanoes...

Well, since "the Bermuda Triangle" tends to expand to include any slightly mysterious happening (including cases where what happened is well documented, e.g. Flight 19; basically they messed up a routine navigation exercise) that might be somewhere that the geographically challenged think of as somewhere appropriate, any explanation is as good as the next one.

Statically there are no more incidents in that area than any other, given the density of shipping etc.

 

[mjcoon]

Well, since "the Bermuda Triangle" tends to expand to include any slightly mysterious happening (including cases where what happened is well documented, e.g. Flight 19; basically they messed up a routine navigation exercise) that might be somewhere that the geographically challenged think of as somewhere appropriate, any explanation is as good as the next one.

Statically there are no more incidents in that area than any other, given the density of shipping etc.

The point was the implications of gassing for navigation, not the Triangle specifically!

 

[KeithMD]

Sinking a Ship with Bubbles I Bermuda Triangle I BBC Studios

 

[AntarcticPilot]

The point was the implications of gassing for navigation, not the Triangle specifically!

It is theoretically possible, but extremely unlikely. It has been put forward as an "explanation" of Bermuda Triangle sinkings ( see Bermuda Triangle - Wikipedia) but in that area, the USGS reckons that outgassing hasn't happened for many thousands of years.

Gas clathrates are a well-known phenomenon, but the point is that they are stable ; they couldn't form otherwise.

 

[KeithMD]

It turns out there's a Part Two to the story.

It’s rarely acknowledged, however, that most volcanic activity on Earth occurs beneath the sea. Submarine volcanoes are pretty much ubiquitous in all of the world’s major oceans and it’s estimated that 75% of the Earth’s magma output comes from mid-ocean ridges.

Underwater volcanoes: How ocean colour changes can signal an imminent eruption

And in some places we wouldn't normally think of as "hot". Like some volcanoes that are active underneath the Antarctic ice sheet.

Subglacial Volcanoes

 

[Stemar]

True - but they are a hazard for certain forms of navigation. There aren't many submarine drivers on YBW - or are there?

The U.S. submarine fleet’s biggest adversary lately hasn’t been Red October. In 2005, the nuclear-powered USS San Francisco collided with an underwater volcano, or seamount, at top speed, killing a crew member and injuring most aboard. It happened again in 2021 when the USS Connecticut struck a seamount in the South China Sea, damaging its sonar array.

Shades of the lighthouse joke, though not so funny for those on board.

 

[AntarcticPilot]

It turns out there's a Part Two to the story.

It’s rarely acknowledged, however, that most volcanic activity on Earth occurs beneath the sea. Submarine volcanoes are pretty much ubiquitous in all of the world’s major oceans and it’s estimated that 75% of the Earth’s magma output comes from mid-ocean ridges.

Underwater volcanoes: How ocean colour changes can signal an imminent eruption

And in some places we wouldn't normally think of as "hot". Like some volcanoes that are active underneath the Antarctic ice sheet.

Subglacial Volcanoes

I have published with a leading expert on subglacial Antarctic vulcanism. While there are plenty of dormant or extinct subglacial volcanoes in Antarctica, as far as I know there are no active subglacial volcanoes, and remarkably few active subaerial volcanoes; Antarctica is the least seismically active continent as except for the northern part of the Antarctic Peninsula, it is far from plate boundaries. We'd know about active subglacial vulcanism from seismic records. There is active subglacial vulcanism in Iceland, though.

 

[KeithMD]

While there are plenty of dormant or extinct subglacial volcanoes in Antarctica, as far as I know there are no active subglacial volcanoes, and remarkably few active subaerial volcanoes;

I refer my honourable colleague to the previously mentioned article on subglacial volcanoes in Antarctica (written by Prof. John Smellie).

Professor Smellie has visited and worked on more volcanoes in Antarctica than any other person, living or dead. As a result, he has sometimes been nicknamed ‘Mr Antarctic Volcano’.
Double distinction for Leicester’s ‘Mr Antarctic Volcano’ in New Year Honours

Examples of active volcanoes given by the learned Prof :

1. Mt Erebus, an active Antarctic volcano.
2. Mt Melbourne, another active Antarctic volcano.

Subglacial Volcanoes

If the Prof has mistakenly conflated subglacial volcanoes with surface volcanoes, or alluded to the latter in a confusing way, please send feedback to him. ;-)

Also some more deep ones, only recently found, hopefully all inactive?

"For anyone with an interest in how Antarctica was formed and continues to change, it’s important to understand the role of volcanoes and the ongoing volcanic activity. New volcanoes hidden under the ice ~ Using radar mapping data of Antarctica, a research team from Edinburgh University was recently able to confirm the presence of 91 volcanoes under up to 4km of ice sheets in West Antarctica. Before this announcement, the world already knew about 47 in this part of the continent, making this update significant for Antarctic science moving forward."
Hot And Cold: How Many Active Volcanoes Are There In Antarctica? - Aurora Expeditions™

 

[AntarcticPilot]

I refer my honourable colleague to the previously mentioned article on subglacial volcanoes in Antarctica (written by Prof. John Smellie).
Examples of active volcanoes given by the learned Prof :

1. Mt Erebus, an active Antarctic volcano.
2. Mt Melbourne, another active Antarctic volcano.

Subglacial Volcanoes

If the Prof has mistakenly conflated subglacial volcanoes with surface volcanoes, or alluded to the latter in a confusing way, please send feedback to him. ;-)

Also some more deep ones, only recently found, hopefully all inactive?

"For anyone with an interest in how Antarctica was formed and continues to change, it’s important to understand the role of volcanoes and the ongoing volcanic activity. New volcanoes hidden under the ice ~ Using radar mapping data of Antarctica, a research team from Edinburgh University was recently able to confirm the presence of 91 volcanoes under up to 4km of ice sheets in West Antarctica. Before this announcement, the world already knew about 47 in this part of the continent, making this update significant for Antarctic science moving forward."
Hot And Cold: How Many Active Volcanoes Are There In Antarctica? - Aurora Expeditions™

Both Erebus and Mount Melbourne are subaerial, as John knows quite well - he was my coauthor on a paper about Deception Island (the other definitely active volcano in Antarctica) and colleague for many years!

 

[newtothis]

As a New Zealander old enough to remember flight 901, Mt Erebus is kinda sticky uppy and not very sub-anything.

 

[[3889]]

I have published with a leading expert on subglacial Antarctic vulcanism. While there are plenty of dormant or extinct subglacial volcanoes in Antarctica, as far as I know there are no active subglacial volcanoes, and remarkably few active subaerial volcanoes; Antarctica is the least seismically active continent as except for the northern part of the Antarctic Peninsula, it is far from plate boundaries. We'd know about active subglacial vulcanism from seismic records. There is active subglacial vulcanism in Iceland, though.

Voclanos neither require proximity to plate boundaries nor seismicity. Hawaii is thousands of miles from the nearest boundary. The 2022 Tongan submarine eruption generated a tsunami and gasified the overlying water column to the extent that no vessel could remain bouyant.