Underwater monowai volcano eruption and collapse

Team observes rapid change in underwater volcano Monowai

A research team out to perform routine mapping of the seafloor some 400 kilometers southwest of Tonga, found that one volcano, named Monowai, changed dramatically over just a two week time span. In an apparent underwater eruption, the volcano collapsed in one part and added almost 80 meters of height in another. The team has described their findings in a paper published in the journal Nature Geoscience.

Read here

More information: Rapid rates of growth and collapse of Monowai submarine volcano in the Kermadec Arc, Nature Geoscience (2012)



This volcano is a part of the 94 volcanos along the Kermadec Tonga arc, the summit is approximately 132 metres (433 ft) below sea level, considerably above the level of the nearby Tonga and Kermadec Trenches. The summit's position and depth changed between 1998 and 2004, due to a landslide and eruptive regrowth. A 1500 metre deep caldera, 13 by 8 km, lies 5–15 km NNE of the seamount's main cone.



Source 1: Huffington post
Source 2: Nature
Source 3: Wiki

Very cool, if we could have seen that as it happened. Would have really been great to have been able to hear it underwater as well.

Just thinking I bet that increases the water temp tremendously. Not like we need that it seems and thinking if this could cause some of the sea life suddenly dying we have heard about?

Originally posted by Connman
Very cool, if we could have seen that as it happened. Would have really been great to have been able to hear it underwater as well.

Just thinking I bet that increases the water temp tremendously. Not like we need that it seems and thinking if this could cause some of the sea life suddenly dying we have heard about?

Yes, and that's a good question. Apparently and according to the Huffington post, a team of geologists was just above the volcano where it erupted...!!
They says that sea's color changed to yellow-green and that there was a very strong smell, like rotten eggs with gas bubbles rising above the volcano... Not a word about the temperature though.

Using advanced bathymetry tools, the scientists saw that a large section of the volcano's flank had collapsed — a volume equal to about 630 Olympic-size swimming pools. The peak of the volcano, however, had grown by 236 feet (72 meters), adding 3,500 swimming pools' worth of volume to the summit.

reply to post by Connman


After reading the article I was thinking the same thing as you. It would be interesting to see the difference in water temperatures within the time period. And also to look at the direction of the water movement. I don't know much about Oceanography, but if I have time later I'm gonna do some snooping around to see if I can answer our questions.

A similar event occurred at the Loihi Seamount, south of the island of Hawaii, in 1996.

SeaBeam surveys documented the bathymetric changes at Loihi summit [see Fig 2] corresponding to the seismic swarm. Pele's Vents, previously the prime locus of hydrothermal activity at a depth of 980m, has collapsed forming a pit crater (Pele's Pit) approximately 600 m in diameter with its bottom 300 m below the previous surface. Portions of the West Pit rim and areas to the north have faulted down several meters towards the summit center, bisecting Pisces Peak.

Hydrothermal activity was observed.

Intense hydrothermal plumes resulting from the seismic event were studied using hydrocasts (vertical water sampling at a single site) and tow-yos (sampling by an instrument package raised and lowered behind a moving ship). Temperature anomalies of 0.5°C were common during the RRC in the water column around the summit at depths of 1050-1250m, with anomalies of 0.1°C at distances >8 km [see Fig 4 below]. In contrast, mid-ocean ridge plumes typically have maximum anomalies of 0.02-0.1°C, although event plume anomalies of up to 0.3°C have been observed (e.g., Baker et al. 1987). One surprise was the observation of a very intense plume at 1600-1800 m depth at a “background” station 50 km NNE of Loihi.

www.soest.hawaii.edu...

Originally posted by Connman
Very cool, if we could have seen that as it happened. Would have really been great to have been able to hear it underwater as well.

Just thinking I bet that increases the water temp tremendously. Not like we need that it seems and thinking if this could cause some of the sea life suddenly dying we have heard about?

Really good question. I hadn't considered that the stories of animals washing up on the beaches could have been results of underwater volcanoes. It would be very interesting to look back at the reports of mass beachings and compare to known eruptions to see if there is a link.

Originally posted by elevenaugust
Huffington post[/url], a team of geologists was just above the volcano where it erupted...!!
They says that sea's color changed to yellow-green and that there was a very strong smell, like rotten eggs with gas bubbles rising above the volcano... Not a word about the temperature though.

Sounds like there was a lot of methane involved. The temperature part would be a very interesting thing to investigate and could tell us things about a myriad of topics from animal deaths up to weather patterns/climate.

reply to post by Phage

So if I understand correctly, these event really don't raise the temperature's that much. So thinking that events like this could cause death's in marine animals is miniscule?

reply to post by crappiekat

I imagine any critters nearby would have a tough time of it but there is a lot of water in the ocean. It absorbs and distributes heat pretty well.

I think noxious exudations would be more of a problem for sea life than heat.

reply to post by Phage

Thank you Phage.

So can they measure the consentration of the noxious fumes in the area and follow where the flow travels?

reply to post by crappiekat

I don't see why not. But they don't seem to have had the equipment in the water at the time.

reply to post by Phage


So exactly how does that work? Do they have to ask for the equipment and wait for someone to say OK ? Or is it, they were just surprised by as the article said and the time for testing was just too late? Can they now set up the equipment and watch the numbers and guesstimate by watching the flows as they would be now? And would it even be worth the effort.

reply to post by crappiekat

I'm not really sure.

I know Loihi had been under study for a while so some of the equipment was probably on site at the time.
In looking further at the article I can see that some testing showed increased levels of dissolved CO2 but that seems to be about it.

reply to post by Phage


Well, that kinda blows. It really stinks when you get into a story like this and you hit a brick wall. Well I guess I will make this a favorite and hope that someone can find some info on this story. I think this is one to follow. This story may give us answers to alot of questions.