New undersea eruption underway in the northern Mariana Island

Sarigan Island in the northern Mariana Islands. An undersea eruption appears to be underway south of the island.

Thanks to the watchful eye of Eruptions readers, we had an inkling of this eruption the other day, but now we have confirmation that an undersea eruption is underway in the northern Mariana Islands. The exact volcano erupting is unknown, but it appears to be between Anatahan and Sarigan (see below) - both active volcanoes in the Marianas - at a depth of 300 meters. The eruption has been described by the USGS as hot water vapor and an ash plume that might have reached as high as 12 km (40,000 feet) while observers/residents on Sarigan Island heard a large explosions and minor ash over weekend. The eruption has prompted the leader of the Commonwealth of the Northern Mariana Islands to declare a state of emergency.

Map of the Mariana Islands.

Anatahan had its first historical eruption in 2003 and erupted as recently as 2008. Sarigan has not had any known historical eruptions, but two seismic swarms were centered at the volcano in August 2005. Holocene lava flows on the flanks of the volcano are the only signs of geologically recent activity at Sarigan. Some of you might also remember Sarigan as Mystery Volcano Photo #4.

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I've been following this at the USGS one new thing I learned is that this is a Commonwealth of the US. That was a shock I keep learning at this blog a little bit of everything amazing at my age.

no webcams for this volcanoe 2 islands were evacuated 7 people on one and 9 on the other. The did report a shockwave too.

I visited Sarigan in July of last year.

In an area of ocean north of Sarigan we came across a film of yellow sulfur covering the water. I've also heard stories of fishermen coming across spots where the water was bubbling out gas from somewhere below.

Heaven forbid, but if we were ever to enter into another period of relative worldwide inactivity, I'd be game for another Volcano Mystery Photo. With all the new readers, the competition might be rather stiff!

Re: Plate Tectonics

Here is a nice little teaching-aid to the above which some may find interesting.(E.g. helps to explain: faulting/volcanoes/ridges/rifts/linear lakes etc. using useful maps.)

Click here:

@Angelo: were you there for a fishing competition? That's a pretty remote island.

@Renee: Yes, CNMI (a collection of islands) is a US Commonwealth while nearby Guam (a single island) is a US Territory. Some time in the past the CNMI was self-governing but due to widespread abuse the US Congress restricted the government's powers and still largely controls the islands. One of the islands (Farallon de Medinilla) is a bombing range and sea vessels aren't allowed near it. The nuclear attacks on Japan were launched from the CNMI's largest island Tinian.

By MadScientist (not verified) on 30 May 2010 #permalink

A correction to my English for my previous post (no. 11)

"greeted BY/treated TO". BOTH apply here!

We've got another case of how the news media bring things to new dimensions: "Giant ash cloud threatens flights in the Pacific" ( The source of the "giant" cloud is Yasur in Vanuatu, and reading the full report, you learn that the ash plume is about 1800 m tall. That's not really gigantic to be honest. But what is true is that Yasur, another of those volcanoes treated a bit like a "tourist toy volcano", seems to show considerably increased activity, and access to the active crater has been prohibited.

@Dagmar, Appears to be ocean and wind noise. Just normal background noise. There is a storm system approaching Iceland, so the plots are going rise until it passes over.

@Jón #15, thank you as always for keeping us from misinterpreting signals that might be anything from volcansim/magma movement, human activity, and meteorological conditions!

@Dagmar #14, always look at the long-term graph in order to see the current levels of tremor in comparison with the levels during the eruption:

(Boris): I seem to recall reading that Yasur's status as a tourist attraction has in the recent past been promoted by the Vanautu government..probably as a source of tourist money, since the country is notably impoverished (but has plenty of active volcanoes) A South Pacific equivalent to Stromboli, except that Yasur is NOT Stromboli

(Erik): Re the Sarigan -or near Sarigan- eruption. A 12km ash column from a vent 300m, that's over 900 feet, below the surface? Given the inhibiting effect of even a shallow depth of water, that must have been some blast, surely?

@mike don #17, also Stromboli is a volcano to be taken VERY serious. Like Yasur (and any other volcano) it is capable of producing very powerful and dangerous explosive activity. Furthermore, every few years to decades, Stromboli delivers lava flows into the sea (last times, 2002-2003 and 2007). An explosion on 5 April 2003 covered the entire summit area - where a few months earlier there would be hundreds of visitors every day - with about 0.5 m of pyroclastics. Luckily all acess to the volcano had been prohibited for several months, because a violent explosion was expected. Also during the past 12 months there have been a number of quite strong explosions, and access to the summit is currently forbidden.

Boris, I wasn't intending to imply that Stromboli shouldn't be taken seriously..but just to note that unlike Stromboli, Yasur doesn't have a convenient natural 'viewing platform' -tourists at Yasur would actually be on the crater rim (and the access road to the summit brings them to a point near the most active vent) And there are no 'refuge' shelters on Yasur to protect against inconvenient bombs, exposure is near complete

Thanks Boris and Jón!

@Mike, I know you weren't intending to downplay Stromboli :-D ... I just wanted to make clear to everybody else that Stromboli is a potentially very dangerous volcano, but you're right, access to Yasur is much more easy (already because it's just one-third the height of Stromboli) and visitors get to the very crater rim, whereas at Stromboli the activity can be viewed from somewhat greater and slightly safer distance. Shelters have been built at Stromboli after many events when tourists at the summit were showered with ejecta from "larger-than-normal" explosions in the 1990s, one death in 2001, and the very large 2003 explosion.

@Boris - Hi! I was in Stromboli back in March and activity there was pretty spectacular and as you mentioned the summit area was off limits. But from the 400m vantage point the view was still great.

I'm hoping to get to Vanuatu in July if activity is still strong and hopefully capture the show in full HD. I'll certainly post any results here if I get anything good.


@Jón, What about HAU and SNB station? Is it also affected by meteorology? That is the plot which seems to be rising the most.

Winds are currently at around 6-8m/s according to the wind speed meter on your helicorders page so I guess that would cause the waves from the atlantic to affect the southern most stations but the ones inland?

By Daniel, swe (not verified) on 31 May 2010 #permalink

Good morning volcano world - sorry I have to be gone all day, will catch up tonite...thanks for all these new posts, very interesting.

By birdseyeUSA (not verified) on 31 May 2010 #permalink

Sorry for beeing "pushy" but i am by nature curious. :-) Always pushing and try to dig deeper in answers.

There seems to be alot of seismic activity. In the last 48 hours there has been 132 recorded tremors of different magnitude all over iceland. At the same time the tremor charts shoot almost straight up and continues to do so.

As i wrote previously the winds seem to keep at a stable level around 5-10m/s and that explains alot of action in the coastal regions. But still i find HAU and SNB to be a bit strange since the tremors keep increasing at a steady rate all the time (looks like a skislope).

By Daniel, swe (not verified) on 31 May 2010 #permalink

Aye, there's a tad more creaking and groaning than often before.

By Reynir, .is (not verified) on 31 May 2010 #permalink

#26) What is going on with Lady E?? The 10 min Tremor Plots keep increasing. The Mulakot web-cam show what looks like a thin coating of ash on the persons home in pictures #2 & #4. The THOR and the HVO web-cams are shrouded in a very low cloud of either ash or ash??

Is there any local reports from that area? Thanks :O)!!

By Robert Bordona… (not verified) on 31 May 2010 #permalink

I wasn't fishing, I was Scuba diving. The trip I went on will be featured in a story in Outside Magazine next month. The issue comes out on June 8. It is the July issue. We visited all of the islands in the archipelago and dove the crater of one of the underwater volcanoes.

I agree with #27, definitely looks like ash at Mulakot, would Daniel's quote @23 of a wind speed of 6-8m/s be enough to pick up and transport existing deposits?

#23 #28 The 6-8m/sec wind is near 10-15 MPH. That is an adequate speed to stir up the layers of ash and dust.

#28, has there been any word in the news, or on local radio about the increasing tremor movement in Iceland? Any reports from the great people living near Lady E? The tremor plots may be influenced by the waves of the sea and the wind, however it appears that the tremor plots for all the seismic locations around Lady E are continually increasing. The Iceland Met will put out an update tomorrow :O(..

I want to say the people in Iceland and Sweden are a real pleasure to communicate with. You are all very polite and quite candid in your responses and your English is excellent. Thanks :O)!!!

By Robert Bordona… (not verified) on 31 May 2010 #permalink

Folks the HVOL web-cam has cleared partially, it appears a very large ash plume is rising from the clouds surrounding Lady E!!

By Robert Bordona… (not verified) on 31 May 2010 #permalink

I am new to this site and what a great place to visit! No arguing here...just great information for geology nuts like myself. Thank you all sooooo much for making this an educational site with honest insights.

By John Finch (not verified) on 31 May 2010 #permalink

#34/ Thanks for the quick response, If you hear or see anything new on Lady E, please keep us updated.

Off the Weather Underground Weather Blog I frequent, there was a post of the Vanautu Volcano posted below:

31. AussieStorm 2:25 PM GMT on May 31, 2010 Hide this comment.
Ash cloud threatens Pacific flights

* From correspondents in Auckland
* From: AFP
* May 31, 2010 7:45PM

A GIANT plume of volcanic ash is threatening villagers in Vanuatu and disrupting flights in the Pacific, scientists and officials say.

Forecasters in New Zealand said the cloud, spewing from Vanuatu's Mount Yasur volcano, was about 1800 metres high and covered an area of about 340 square kilometres.

Tourists have been urged to stay away from the volcano on Tanna island, which has disrupted domestic flights in neighbouring New Caledonia.

Peter Korisa of the National Disaster Management Office, who is on Tanna to assess the situation, said lava and hot rocks had been spewing from the volcano and ash was raining down on nearby villages.

"There are 6000 people in the villages around the volcano, we're not moving them out yet," Mr Korisa said.

"All tourists and tourist operators have been asked to not access the volcano. The access is restricted."

Tristan Oakley, an aviation forecaster with New Zealand's Meteorological Service, said authorities had issued an advisory and it was up to airlines to avoid the affected area or cancel flights if necessary.

The plume has forced New Caledonia's AirCal to cancel two internal flights and delay another, although disruption remains tiny compared to the havoc recently seen in Europe - including a week-long shutdown in the continent's north in April.

Air Vanuatu local supervisor David Dick said flights were still running between the South Pacific country's capital, Port Vila, and Tanna island, while tourism officials also said the industry was unaffected.

However, Australia on Friday issued a travel advisory saying visitors were now barred from the volcano.

"Public access to the volcano is now strictly prohibited and people living in the risk zone should move to safer areas," the advisory said.

Vanuatu was rocked by a 7.2-magnitude earthquake on Friday, prompting a brief tsunami warning.

The archipelago, which lies between Australia and Fiji and north of New Zealand, was hit by three major quakes in October 2009.

By Robert Bordona… (not verified) on 31 May 2010 #permalink

Being new to the volcano watching world I'm curious as to the amount of volcanic activity in the past 30 or so days. Is this normal? I've been trying to find what the average is for yearly eruptions but I'm having no luck. I'm hoping one of the great minds here can clue me in. :o)

By Janet, Tx (not verified) on 31 May 2010 #permalink

I found a site, "Global Volcanism Program" which has a study listed on annual eruptions and shows that the average is 50-70 per year and has been fairly consistent since 1960. Hope this helps.

By John, California (not verified) on 31 May 2010 #permalink

John ~ Thanks! I'm off to read more. :)

By Janet, Tx (not verified) on 31 May 2010 #permalink

1 m/s equals ca. 2.24 mph or 1.94 knots. You can check that by noting that 1 m/s = 3600 m/hr (3.6 km/hr) and then applying the appropriate conversion factors: 1 statute mile = 1609 metres and 1 nautical mile = 1852 metres. Too bad you Merkins aren't using the Scandinavian statute mile. One of them is 10 km sharp.

By Reynir, .is (not verified) on 31 May 2010 #permalink

In Iceland: Earthquake swarm around 8 hours ago at Kistufell (part of the Bardarbunga/Grimsvotn/Laki/Vatnajokull system). Also, a few earthquakes on a mountain 14 km west of Hekla

It is very sad that most people are not aware that the USA has territories and islands. In the Caribbean it's the US Virgen islands and Puerto Rico and most don't realize that they are also US Citizens.

@Daniel, swe. It has been awhile since I did see a volcano tremor on my sensor and IMO plots. Now I just see background noise. There might be slightly higher background noise on some of Eyjafjallajökull sensors due to geo-thermal activity in Eyjafjallajökull. But that is about it.

The small unconfirmed (at the moment) eruption over the weekend appears to have lasted only few hours. It is long over now.

Now there is wind and the ocean on the tremor plots. Like normal when nothing is happening.

@Gordon 31 - oh, very good... : )

By birdseyeUSA (not verified) on 31 May 2010 #permalink