Vikings Volcanic Activity Thread

[Guest Shetland Coastie]

SOMETHING STIRRING IN COLOMBIA?

In recent days there have been several reports of increased activity at 3 of Colombias volcanos. I have already posted about the increased activity at Nevado del Huila and there has been further activity at two more. On 16 Sept there was a Mag 2 earthquake at a depth of less than 1km below Galeras. This could well indicate the movement of magma near the surface. Also on 13 Sept there was a sizeable (Mag 5.3) quake underneath another Colombian volcano, Nevado del Ruiz.

Could be something in the offing at one and maybe more of these volcanos shortly and well worth keeping an eye on.

Edited September 18, 2008 by Shetland Coastie

[Guest Shetland Coastie]

ERUPTION! - PITON DE LA FOURNAISE - REUNION ISLAND

Piton de la Fournaise, which lies on the French island of Reunion in the Indian Ocean, began erupting at 1530 local time yesterday. The activity began with an upturn in seismic activity on 15 Sept and has erupted through a fissure in the western wall of the main Dolomieu crater, which collapsed after the last major eruption last year.

Eruptive activity has so far been limited to the area of the Dolomieu crater with lava forming a lake within the crater itself. The volcano lies on top of the Reunion Hotspot, a volcanic hotpsot which has been active for some 65 million years and is believed to have been responsible for the eruption of the Deccan Traps, a vast flood basalt which covers much of central India. This hotspot is also thought to have been responsible for the creation of the Maldives and Mauritius as well as Reunion.

[Louby]

How long since this one last erupted Bob?

[Guest Shetland Coastie]

There was a major eruption in April 2007 which caused the main Dolomieu crater to collapse in on itself. Piton de la Fournaise is frequently active, although its eruptive style is very similar to Kilaeau in Hawaii, i.e. effusive (it oozes lots of lava) rather than explosive so it tends to produce prodigious amounts of lava without the fireworks of more explosive volcanos.

[The PIT]

A very active Volcano with over 150 eruptions since the 17th century. Like Kilauea it's one very active hot spot volcano.

[Guest Shetland Coastie]

INTERESTING EARTHQUAKE ACTIVITY AT YELLOWSTONE

Now this may well be nothing but over the last couple of days there has been an upturn in earthquake activity at the Yellowstone Caldera. There have been, since 0812 local time yesterday, 6 earthquakes greater than Mag 2, located in the same area and at shallow depth, details as follows.

0812 25/09 Mag 2.6 @ 0.8km depth

0938 25/09 Mag 2.5 @ 0.4km depth

0939 25/09 Mag 2.2 @ 0.0km depth

0944 25/09 Mag 2.4 @ 0.4km depth

1207 25/09 Mag 2.9 @ 2.6km depth

1236 25/09 Mag 2.2 @ 0.8km depth

This could, of course, be related to the ongoing hydrothermal activity in the caldera. It could also, however, be indicative of the movement of magma at a shallow depth, bearing in mind that the whole caldera is undergoing uplift at the moment as well. It seems fairly significant as that is a swarm of reasonable sized earthquakes in the same area (44-45km ENE of Warm River) at shallow depth. I've sent an e-mail off to USGS to see what they make of it.

Link to USGS Yellowstone earthquake map

Edited September 26, 2008 by Shetland Coastie

[Guest Shetland Coastie]

INCREASE IN ACTIVITY - GALERAS - COLOMBIA

INGEOMINAS reports an upturn in activity at Galeras during the past week. During an overflight on 19 Sept, incandescence was noted in the main crater. Also, thermal images revealed a significant thermal anomaly in the crater at a temp of 550C. SO2 emissions are also elevated, measuring between 3,000 tonnes and 8,200 tonnes per day.

[0000]

INTERESTING EARTHQUAKE ACTIVITY AT YELLOWSTONE

Now this may well be nothing but over the last couple of days there has been an upturn in earthquake activity at the Yellowstone Caldera. There have been, since 0812 local time yesterday, 6 earthquakes greater than Mag 2, located in the same area and at shallow depth, details as follows.

0812 25/09 Mag 2.6 @ 0.8km depth

0938 25/09 Mag 2.5 @ 0.4km depth

0939 25/09 Mag 2.2 @ 0.0km depth

0944 25/09 Mag 2.4 @ 0.4km depth

1207 25/09 Mag 2.9 @ 2.6km depth

1236 25/09 Mag 2.2 @ 0.8km depth

This could, of course, be related to the ongoing hydrothermal activity in the caldera. It could also, however, be indicative of the movement of magma at a shallow depth, bearing in mind that the whole caldera is undergoing uplift at the moment as well. It seems fairly significant as that is a swarm of reasonable sized earthquakes in the same area (44-45km ENE of Warm River) at shallow depth. I've sent an e-mail off to USGS to see what they make of it.

Link to USGS Yellowstone earthquake map

Thanks for the linky Bob,does this Caldera release pressure in small ways like a conventional volcano? By that I mean small eruptions etc or is the nature of a caldera just one all mighty boom every few eons?

Edited September 27, 2008 by hannegan

[Guest Shetland Coastie]

Thanks for the linky Bob,does this Caldera release pressure in small ways like a conventional volcano? By that I mean small eruptions etc or is the nature of a caldera just one all mighty boom every few eons?

It releases pressure through the major hydrothermal activity that is a constant feature of the caldera, such as geysers like 'Old Faithful'. However, the magma chamber beneath Yellowstone is huge and if this gets full or nearly full the pressure is too great and as you say 'boom'. The latest assessement done a couple of years ago by USGS stated that they thought that whilst a monumental 'supervolcano' type eruption was unlikely in the near future there was the possibility of a major one, possibly bigger than say Mount St Helens, which in itself would obviously have a major impact both on the continental US and globally. Such an eruption would have climactic import.

Edited September 27, 2008 by Shetland Coastie

[0000]

Pretty much yes. It releases pressure through the major hydrothermal activity that is a constant feature of the caldera, such as geysers like 'Old Faithful'. However, the magma chamber beneath Yellowstone is huge and if this gets full or nearly full the pressure is too great and as you say 'boom'. The latest assessement done a couple of years ago by USGS stated that they thought that whilst a monumental 'supervolcano' type eruption was unlikely in the near future there was the possibility of a major one, possibly bigger than say Mount St Helens, which in itself would obviously have a major impact both on the continental US and globally. Such an eruption would have climactic import.

Sorry for the questions Bob,what would the signs be for a major pop?Would there be sufficient warning?

Also thank you for answering my previous question

[Guest Shetland Coastie]

Sorry for the questions Bob,what would the signs be for a major pop?Would there be sufficient warning?

Also thank you for answering my previous question

Earthquakes, major inflation of the caldera and a huge build up in volcanic gases which would probably manifest in a huge increase in the hydrothermal activity. Yes we'd get plenty of warning. Volcanos can and do go 'pop' with little or no warning but a caldera the size of Yellowstone would let us know it was ready to go! Also, it is one of the most intensively monitored volcanic sites in the world.

Edited September 27, 2008 by Shetland Coastie

[0000]

Earthquakes, major inflation of the caldera and a huge build up in volcanic gases which would probably manifest in a huge increase in the hydrothermal activity. Yes we'd get plenty of warning. Volcanos can and do go 'pop' with little or no warning but a caldera the size of Yellowstone would let us know it was ready to go! Also, it is one of the most intensively monitored volcanic sites in the world.

Thanks again,it's a pleasure to be able to ask someone so well read and informed on such a fascinating subject.Well done and keep up the great work!

[The PIT]

Direct link too yellowstone yvo site.

http://volcanoes.usgs.gov/yvo/

Nothing untoward at the moment.

Earthquakes, major inflation of the caldera and a huge build up in volcanic gases which would probably manifest in a huge increase in the hydrothermal activity. Yes we'd get plenty of warning. Volcanos can and do go 'pop' with little or no warning but a caldera the size of Yellowstone would let us know it was ready to go! Also, it is one of the most intensively monitored volcanic sites in the world.

Forgetting St Helens which showed very little signs for the last session of dome growth until the eruption started. I've always wondered whether the equipment was working or not or whether the magma was stored at a shallow depth for many years before which would account for the low gas content for entire eruption.

[The PIT]

I thought hydrothermal activity was just a by-product of volcanoes. It's not actually the volcano itself releasing pressure.

Both to be honest basically it's realising energy of the magma body. As long as this method can cool the magma body and there's no fresh injection of magma it acts like a pressure valve quietly releasing energy.

[Guest Shetland Coastie]

I thought hydrothermal activity was just a by-product of volcanoes. It's not actually the volcano itself releasing pressure.

A bit of both really Wibs. Hydrothermal vents such as fumaroles or solfataras usually occur in or around volcanos and are driven by the same heat source as their parent volcano so not so much a by-product but an additional symptom of volcinic activity. They can, however occur at plate boundaries (such as black smokers under the oceans at places such as the Mid-Atlantic Ridge).

Yellowstone has some 4000 fumaroles in the park and all of these are driven by the same heat source, i.e. the magma chamber underneath Yellowstone which could also produce a volcanic eruption.

Hydrothermal vents such as fumaroles can form in or on volcanos as well as temporarily on lava flows during a volcanic eruption. Often, hydrothermal activity is a left-over of volcanic activity as well, as there are many areas in the world where there is hydrothermal activity but no volcanic activity any more.

Sometimes, when it appears that a volcano is building up to an eruption, the eruption will suddenly die down again because the pressure has been released through 'de-gassing' through fumaroles and other hydrothermal activity. This happened to one in Indonesia last year (I forget the name) where we were all sitting on this thread waiting for it to erupt and instead it de-gassed through the crater lake at the summit and the eruption died down again.

Bear in mind that what can cause a volcano to erupt explosively is its gas content and if this is released through fumaroles etc then the pressure for an eruption is not so great so its a bit like the safety valve on a pressure cooker.

The picture below is of a hydrothermal vent emitting steam and SO2 from within the main Halema'uma'u crater at the summit of Kilaeua.

Edited September 27, 2008 by Shetland Coastie

[The PIT]

Also what can cause a Volcano to explode is whether the vent is blocked or not. If the vent is blocked pressures build until they blow the block out creating an explosive eruption. The size of the eruption normally depends on the period of quietence and the size of the magma chamber below the volcano. Large chambers don't always mean a large eruption rather it's a case of how the pressure is released.

Other factors include slope failure as Volcano's are unstable due to ash lava then ash eruptions which build up layers of the volcano. There's also the chemical reaction of the gasses and rocks that can change parts of volcano's to clay.

St Helens 80's was largely due to slope failure basically a landslide which exposed the injection of ( dome) lava too low pressure and hence the explosion.

Popocatepetl is a case of a volcano which has an open vent. It just smokes and puts out the odd puff of smoke and ash and is unlikely to go bang in the near future.

[Guest Shetland Coastie]

Indeed PIT. Also the viscosity of the magma can play a part as can the intrusion of water which can lead to a violent reaction between the hot magma and cold water known as a phreatic eruption.

To give an example where viscosity is important, Kilaeau in Hawaii has lava which has a very low viscosity, i.e. it is essentially very runny. Because of this it is rare for Kilaeau to erupt explosively but rather effusively, i.e. lots of runny lava which just runs off into the sea. This builds a volcano which is very flat like Kilaeua callad a shield volcano. Piton de La Fournaise on Reunion Island is another example. Large stratovolcanos (classic cone shaped) have lava of a much higher viscosity, i.e. thick and sticky, this helps build the steep sided volcano because it doesnt run off so well but can also mean it is prone to more violent, explosive eruptions.

Edited September 27, 2008 by Shetland Coastie

[The PIT]

If anyone wants a good book on the dangers of a volcano should look at "No apparent danger" written by Victoria Bruce a good read and can be bought from from Amazon.

[LadyPakal]

You need to look at the type of material a volcano has previously erupted to know what to expect - if the volcano is acid (felsic - has a lot of silica in it) or basic (mafic - has a lot of magnesium and iron). This is a good sign of the type of eruption you can expect. Basic volcanoes (the ones that erupt basalt - like the Hawaiian ones that make the shield type volcanoes or low angle cones) are none explosive as the lava has a lower viscosity than the acid types and doesn't tend to form plugs. The ones you need to watch for are the acid ones - these make the typical higher angle cone shaped volcanoes and also the 'hidden' collapsed caldera types, like Yellowstone and Toba. Between eruptions they form pretty hard plugs in the main vent which go off with a bang once the pressure has built up enough. These explosive acid volcanoes are also the ones that can make the nuée ardente/pyroclastic flows seen in the Mt St Helens eruption and when Krakatoa went bang.

[Guest Shetland Coastie]

You need to look at the type of material a volcano has previously erupted to know what to expect - if the volcano is acid (felsic - has a lot of silica in it) or basic (mafic - has a lot of magnesium and iron). This is a good sign of the type of eruption you can expect. Basic volcanoes (the ones that erupt basalt - like the Hawaiian ones that make the shield type volcanoes or low angle cones) are none explosive as the lava has a lower viscosity than the acid types and doesn't tend to form plugs. The ones you need to watch for are the acid ones - these make the typical higher angle cone shaped volcanoes and also the 'hidden' collapsed caldera types, like Yellowstone and Toba. Between eruptions they form pretty hard plugs in the main vent which go off with a bang once the pressure has built up enough. These explosive acid volcanoes are also the ones that can make the nuée ardente/pyroclastic flows seen in the Mt St Helens eruption and when Krakatoa went bang.

Indeed and whilst thats a good guide it isn't always the case. Volcanos can and do undergo subtle changes to their chemistry which can make them erupt differently from time to time. Kilaeua normally doesn't erupt explosively but it does from time to time. Likewise, Etna can erupt explosively from the summit crater but can also erupt effusively from flank rifts.

[LadyPakal]

Sorry, I'd had a skinfull when I wrote that!

[Guest Shetland Coastie]

Sorry, I'd had a skinfull when I wrote that!

Nae bither quine! Ave a habit o deein at masel

Edited September 28, 2008 by Shetland Coastie

[LadyPakal]

Better now after a long sleep. It's funny what you can remember when drunk tho' - it's been a loooong time since my Uni days (studied Geology). I'm starting to think I should have done my exams inebriated... mights have got a first! One of the chaps on my course is now a Professor of Vulcanology - saw him on a program about Anak Krakatau - he was trying to work out which direction the pyroclastic flow would go next time it erupted big time.

Yes, there are always some volcanoes that surprise. That's the fun of it - well, as long as you are far enough away from the explosive ones.

Had an interesting time snowmobiling around Yellowstone a few years ago. The last year it was allowed before they stopped it inside the park in fact. Seeing the steam coming off the hot waters surrounded by deep snow is a fantastic sight. Buffalo & deer hang around the hot springs for the warmth. There were a surprising number of people waiting for Old Faithful to go off. The car park was full of snowmobiles. Wierd to think what will happen there one day.

[Guest Shetland Coastie]

Better now after a long sleep. It's funny what you can remember when drunk tho' - it's been a loooong time since my Uni days (studied Geology). I'm starting to think I should have done my exams inebriated... mights have got a first! One of the chaps on my course is now a Professor of Vulcanology - saw him on a program about Anak Krakatau - he was trying to work out which direction the pyroclastic flow would go next time it erupted big time.

Yes, there are always some volcanoes that surprise. That's the fun of it - well, as long as you are far enough away from the explosive ones.

Had an interesting time snowmobiling around Yellowstone a few years ago. The last year it was allowed before they stopped it inside the park in fact. Seeing the steam coming off the hot waters surrounded by deep snow is a fantastic sight. Buffalo & deer hang around the hot springs for the warmth. There were a surprising number of people waiting for Old Faithful to go off. The car park was full of snowmobiles. Wierd to think what will happen there one day.

Snowmobiling in Yellowstone!!! My idea of heaven

[Guest Shetland Coastie]

CHAITEN

Clear skies and some good views on the Chaiten webcam today!

Chaiten webcam