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Vikings Volcanic Activity Thread


Guest Viking141

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Guest Viking141
Thanks for that Viking, and please keep us updated.

I had not realised that this was the longest non-eruption period for nearly 500 years, and that is extremely worrying.

From Horizon, i gathered that a pyrochlatic flow would take just 15 minutes to reach Naples and kill approximately 2 million people.

What was the VEI of the last eruption, which i assume was standard for Vesuvius??????

Have you seen any pattern to suggest that Vesuvius may be 'waking up'???????

Personally, i would not be suprised if the Pompeon eruption was VEI6 or VEI7.

Hi SB

Yes, given that the usual quiet period for Vesuvius is anything between 18 months to 7.5 years, this current spell is somewhat ominous. It is a known feature of Vesuvius that the longer the quiet spell the more violent the following eruption.

The average for Vesuvius is of the order VEI4-5, which is what current evacuation plans are based on, assuming this figure as the worst case scenario, however, Vesuvius is prone to even more violent eruptions every now and then and I would tend to agree that the AD79 eruption, which destroyed Pompeii and Herculaneum, which is officially classified as VEI5, was probably more likely a VEI6.

Since the 1944 eruption, Vesuvius has entered a phase of "closed-conduit" activty, where the main lava conduit is closed by a lava plug. This is particularly dangerous, as it allows lavas and gases to build up under enormous pressure, before the plug eventually gives way, usually resulting in a major Plinian-type eruption.

The current evacuation plan assumes that the main danger for pyroclastic flows would be within a 7km radius of the central cone. Naples lies outwith this zone and also the prevailing winds in the area suggest that towns to the South and East would be most at risk, this includes Avellino and Salerno which could be prone to ash fall and the resultant collapsed roofs etc.

As an example of what can happen, Vesuvius entered one of these "closed-conduit" phases at the end of the 13th century. During this time the volcano became covered in gardens and vineyards. This all came to a sudden and dramatic end in 1631 when a major eruption buried several villages under lava flows and torrents of boiling water, killing some 3000 people. Major eruptions then continued every few years right up to the 1944 eruption.

Currently, there is no indication of an impending eruption but is a case of "when" not "if" Vesuvius will erupt violently again. Ive had a look at the seismic data from Vesuvius and there doesnt appear to be much happening, but, as we all know, volcanos are unpredictable creatures and this situation could change fairly quickly.

Edited by Viking141
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Posted
  • Location: Sunny Southsea
  • Location: Sunny Southsea

Following the Earthquake and tsunami last week, I thought it would be useful to push a pointer in the direction of the Kurile Islands. It is not uncommon for earthquakes to stimulate volcanic activity, and there are three candidates within 100 km or so of the epicentre: Urataman, Prevo Peak, and Zavaritski; these will be worth keeping an eye on.

:)P

Edited by parmenides3
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Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet

Thanks for that information, and i have done a little reasearch of my own.

According to current thinking, "Sub-plinian eruptions producing about 0.1 km³, such as those of 472 and 1631, have been more frequent with a few hundred years between them. Following the 1631 eruption until 1944 every few years saw a comparatively small eruption which emitted 0.001-0.01 km³ of magma. It seems that for Vesuvius the amount of magma expelled in an eruption increases very roughly linearly with the interval since the previous one, and at a rate of around 0.001 km³ for each year. This gives an extremely approximate figure of 0.06 km³ for an eruption after 60 years of inactivity."

That would mean that if Vesuvius erupted now, we would be looking at a severe or cataclysmic eruption, assuming that the theory held true, making it the strongest eruption since 1631.

3 - Vulcanian/Pelean; severe; 3-15km; 10,000,000m3; Nevado del Ruiz 1985

4 - Pelean/Plinian; cataclysmic; 10-25km; 0.1km3; Galunggung 1982

However "At the International Geological Congress meeting last summer in Florence, Franco Barberi of Rome University called Vesuvius the world’s most dangerous volcano, with a high probability of an explosive Plinian eruption by the end of this century on the order of the one that buried Pompeii."

Interestingly, "So far, no magma has been detected within 10 km of the surface, and so the volcano was, in 2001, at worst only in the very early stages of preparing for an eruption. This status has apparently not changed much to date."

I would stress the word much, because according to an article which i will find the link to, there has been a slight increase in seismic activity, though only slight.

According to seismic data over the last 30 years, the period has observed a low rate of seismic activity, though there have been some relatively intense periods of activity, with the baseline remaining higher than the last each time, this indicates that Vesuvius is moving towards an eruption, though given the seismic data available, i would say that an eruption is 10 to 20 years away, which is consistent with current scientific thoughts of an eruption between 2015 and 2030.

http://www.geotimes.org/apr05/NN_Vesuvius.html

http://en.wikipedia.org/wiki/Vesuvius

http://www.springerlink.com/content/vrd026l36hqrwq0v/

Edited by summer blizzard
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Guest Viking141

Hi P3

Indeed the Kuril Islands have a great number of volcanos, 49 to be precise, however,many of them have not erupted in recent history. The most recent were Chiburakchi and Ebeko, both in 2005.

The recent magnitude 8.1 earthquake was centred 240 miles east of Iturup Island (known as Etorofu to the Japanese) so geographically the nearest volcanos to the epicentre would be those on Iturup;

Atsonpuri, Baransky, Bogatyr Ridge, Medvezhia, Chiriup, Grozny, Demon and Golets-Torny. Of these, Medvezhia has been most recently active in 1999. Grozny erupted in 1989, Baransky in 1951 and Atsonpuri in 1932. The rest have been quiet for some time.

Of the three you mention, Zavaritsky last erupted in 1957, Prevo Peak in 1825 approx and no historical eruptions have been known from Urataman.

It will indeed be interesting to see if the earthquake provkes any volcanic activity further down the line.

:)

Thanks for that information, and i have done a little reasearch of my own.

According to current thinking, "Sub-plinian eruptions producing about 0.1 km³, such as those of 472 and 1631, have been more frequent with a few hundred years between them. Following the 1631 eruption until 1944 every few years saw a comparatively small eruption which emitted 0.001-0.01 km³ of magma. It seems that for Vesuvius the amount of magma expelled in an eruption increases very roughly linearly with the interval since the previous one, and at a rate of around 0.001 km³ for each year. This gives an extremely approximate figure of 0.06 km³ for an eruption after 60 years of inactivity."

That would mean that if Vesuvius erupted now, we would be looking at a severe or cataclysmic eruption, assuming that the theory held true, making it the strongest eruption since 1631.

3 - Vulcanian/Pelean; severe; 3-15km; 10,000,000m3; Nevado del Ruiz 1985

4 - Pelean/Plinian; cataclysmic; 10-25km; 0.1km3; Galunggung 1982

However "At the International Geological Congress meeting last summer in Florence, Franco Barberi of Rome University called Vesuvius the world’s most dangerous volcano, with a high probability of an explosive Plinian eruption by the end of this century on the order of the one that buried Pompeii."

Interestingly, "So far, no magma has been detected within 10 km of the surface, and so the volcano was, in 2001, at worst only in the very early stages of preparing for an eruption. This status has apparently not changed much to date."

I would stress the word much, because according to an article which i will find the link to, there has been a slight increase in seismic activity, though only slight.

http://www.geotimes.org/apr05/NN_Vesuvius.html

http://en.wikipedia.org/wiki/Vesuvius

Quite so SB. Although it has been asserted that Vesuvius' eruptions have been progressively less explosive up to 1944, as was pointed out in the Geotimes article you linked to, there have been two major explosive eruptions during this period which have been exceptions to the rule. I think volcanic prediction is even more tenuous than forecasting the weather!!

:)

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Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet

Indeed, i think the main issue at the moment is what type of eruption it will be, which is dependant upon the type of magma, though given that there is a magma plug and a large period of inactive volcanic activity, i would say that there is a higher chance of an explosive eruption than a lava eruption and i would favor a VEI4 eruption.

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Guest Viking141
Indeed, i think the main issue at the moment is what type of eruption it will be, which is dependant upon the type of magma, though given that there is a magma plug and a large period of inactive volcanic activity, i would say that there is a higher chance of an explosive eruption than a lava eruption and i would favor a VEI4 eruption.

Agreed SB and this would follow the long-term pattern for Vesuvius. A long spell of quiesence, followed by a major explosive eruption, followed by many years of Strombolian type eruptions of the kind seen at Etna and then lapsing into quiesence again for the cycle to start again. Question is, how explosive. I would agree certainly VEI4 possibly even VEI5. The link I posted earlier which gives real-time seismic data will be worth checking every now and then.

:D

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Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet

Viking, is it possible that Vesuvius is part of a super volcano?????

"The layer they found beneath Vesuvius stretches across 400 square kilometres (154 square miles), but they were unable to tell how thick it is."

http://news.bbc.co.uk/1/hi/sci/tech/1656722.stm

If that article is correct, then Mount vesuvius is fully capable of a VEI7 or VEI8 eruption.

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Guest Viking141
Viking, is it possible that Vesuvius is part of a super volcano?????

"The layer they found beneath Vesuvius stretches across 400 square kilometres (154 square miles), but they were unable to tell how thick it is."

http://news.bbc.co.uk/1/hi/sci/tech/1656722.stm

If that article is correct, then Mount vesuvius is fully capable of a VEI7 or VEI8 eruption.

Dont think so SB, at least it hasnt been classified as such at the moment. Vesuvius is what is known as a "Somma" volcano i.e. one that is a central cone which has gown up within the caldera of a much larger, older volcano (Monte Somma - hence the name although all volcanos of this type are known as Somma volcanos - the previously mentioned Ebeko in the Kuril Islands is an example).

Also, bear in mind that Vesuvius is part of the much wider surrounding area which is also geologically active, called the Campi Flegrei (Phlegrean Fields) which has, in the past, produced VEI6 eruptions. Much of this ancient caldera lies underwater in the Bay of Naples but also manifests itself on land, most notably in the hot sulferous pools near Naples known as "La Solfatara." It may well be that the magma pool talked about feeds the whole area and not just Vesuvius.

However, the science of "supervolcanos" is relatively new and it is possible that the whole area is a supervolcano a la Yellowstone Park.

Edited by Viking141
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Roundup of some ongoing activity in Guatemala

Three Guatemalan volcanos, Pacaya, Fuego & Santiaguito are undergoing some moderate activity at the moment, according to the latest report from INSIVUMEH (Instituto Nacional de Sismologia, Vulcanologia, Meteorologia E Hidrologia) dated 17th November.

PACAYA - Abundant fumarolic emissions with a white emission cloud covering the south flank of the volcano. Incandescent lava continues to be observed in the north part of the volcano and there are 3 lava flows heading in the direction of Cerro Grande and Cerro Chino.

FUEGO - Several moderate explosions expelled lava to a height of 100m and showered the flanks with incandescent boulders.

SANTIAGUITO - Some lava extrusion to the south and sothwest of the volcano and several landslides of large blocks which reached the base of the volcano and ashfall which reached the towns of Florida and Monte Claro.

(Note: Santiaguito is a comparatively new volcano which has formed in the huge crater created when its parent volcano, Santa Maria, blasted a huge hole in one side (in similar fashion to Mt St Helens) in 1902 in what was the second largest eruption of the twentieth century after Mount Pelee in Martinique(also in 1902)).

post-4448-1164145830_thumb.jpgpost-4448-1164145824.jpgpost-4448-1164145839_thumb.jpg

Pictures of Pacaya, Fuego and Santiaguito (the lower peak in the foreground, the higher peak is Santa Maria)

Edited by Viking141
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Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet

Viking, could we have an update on Krakatoa please????

Are there any volcanoes which have been dormant for over 100 years, these are the more dangerous ones.

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Guest Viking141
Viking, could we have an update on Krakatoa please????

Are there any volcanoes which have been dormant for over 100 years, these are the more dangerous ones.

Im on it! Hope to have something for you later today.

:)

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Krakatoa update

Can I start by saying the common spelling Krakatoa is a misnomer, the proper name of the volcano is Krakatau. As we all know, Krakatau blew itself to pieces in the spectacular eruption of 1883 which cost over 36,000 lives. After a period of quiesence of less than half a century, a new cone appeared from the remnants of the old volcano in 1928. This is now called Anak Krakatau (Child of Krakatau). The explosion of the original Krakatau was of the order of VEI6 - equivalent to 200 megatons of TNT or 13000 times the yield of the first atomic bomb dropped on Hiroshima.

post-4448-1164280774.jpg

Picture is of Anak Krakatau - courtesy Volcanological Institute of Indonesia

Anak Krakatau has been pretty much constantly active since then, going through short phases of quiesence followed by equally short explosive outbursts and the occasional more major eruption, the last of which was in 2001. Since 1951 the new island has grown at the rate of some 5 inches per week and reports in 2005 suggested this rate was increasing, with fresh lava flows adding to the islands area. Anak Krakatau remains a very dangerous volcano. Like many in Indonesia its eruptive activity tends to be highly explosive and it is highly unpredictable, indeed the island has been placed off limits by the Indonesian Government. Anak Krakatau is currently in a quieter phase and is at Aviation Concern Colour Code YELLOW. However, given the nature of this volcano, this situation could change very quickly and it is one worth keeping an eye on.

Edited by Viking141
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Round up of activity from Alaska and Kamchatka

Alaska

Latest information from the Alaskan Volcano Observatory (AVO) suggests four Alaskan Volcanos are showing some signs of unrest, enough to have them at Aviation Colour Code YELLOW. All other volcanos in the region are at GREEN.

FOURPEAKED – Low (but above normal background) level earthquakes continue at Fourpeaked and a persistent steam plume rises above the summit. Nothing unusual has been observed in satellite views obtained this week.

CLEVELAND – Appears to have clamed down this past week with no new observations of ash emissions or thermal anomalies.

VENIAMINOF – Seismicity remains above background levels with intermittent, short-lived bursts of ash and steam from the caldera cone. No indications at the moment that eruption is imminent.

KOROVIN (ATKA ISLAND) – Again seismicity remains at above background levels and the AVO was unable to obtain further information due to the inclement weather conditions.

Kamchatka

KARYMSKY – Remains at Concern Code Colour ORANGE and moderate explosive activity continues. Explosions of ash up to almost 20,000 are possible

BEZYMIANNY – Remains at Colour Code YELLOW. Growth of the lava dome continues. Fumarolic activity was observed on 17th, 19th & 22nd November and a thermal anomaly was noted on 18-19 and 21-22 November.

SHEVELUCH – Again growth of the lava dome continues and ash explosions can be expected at any time.

All other Kamchatka volcanos are at normal activity levels.

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Mount St Helens pictures

A couple of excellent pictures of Mt St Helens taken on 17th November which clearly show the new lava dome in the centre of the crater.

post-4448-1164476202_thumb.jpgpost-4448-1164476211.jpg

Both photographs courtesy John Pallister, USGS

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Posted
  • Location: Lower Brynamman, nr Ammanford, 160-170m a.s.l.
  • Location: Lower Brynamman, nr Ammanford, 160-170m a.s.l.

Cheers Viking. Nice to see it at a different, more informative, angle than from the volcano webcam from Johnston Ridge.

What happened to the massive slab that was projecting at one side of the new mound at a near vertical angle earlier in the year? I forgot to look for a few weeks and it disappeared from mention on the web.

CR

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Guest Viking141
How fast is the new dome on Mt St Helens growing then?

Hi Flaggy

According to USGS the rate of growth of the new lava dome is currently slightly less than 1 cubic metre per second.

Cheers Viking. Nice to see it at a different, more informative, angle than from the volcano webcam from Johnston Ridge.

What happened to the massive slab that was projecting at one side of the new mound at a near vertical angle earlier in the year? I forgot to look for a few weeks and it disappeared from mention on the web.

CR

Hi CR

It probably collapsed which is something that happens regularly. The lava dome extrudes a slab or spine which then collapses under its own weight and wthe whole process begins over again.

Update - the slab you are referring to started to crumble in June 2006 and produced several rockfalls.

Edited by Viking141
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Posted
  • Location: Lindum Colonia
  • Location: Lindum Colonia
Hi Flaggy

According to USGS the rate of growth of the new lava dome is currently slightly less than 1 cubic metre per second.

That sounds quite a lot?

It is hard to get an idea of the size of that dome though. Could do with a little man stood next to it :D

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Guest Viking141
That sounds quite a lot?

It is hard to get an idea of the size of that dome though. Could do with a little man stood next to it :D

It certainly is and gives an idea of just how active Mount St Helens still is. The current height of the new lava dome is over 7,500ft.

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Posted
  • Location: Lindum Colonia
  • Location: Lindum Colonia
It certainly is and gives an idea of just how active Mount St Helens still is. The current height of the new lava dome is over 7,500ft.

That is very impressive! I have a link to the webcam but you just don't get an idea of scale.

Must go and check out the latest earthquake reports :D

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Guest Viking141
That is very impressive! I have a link to the webcam but you just don't get an idea of scale.

Must go and check out the latest earthquake reports :D

Currently, St Helens is undergoing fairly regular Magnitude 1.5 - 2.5 earthquakes, however, yesterday at 2145 UTC there was a larger Magnitude 2.9 earthquake although this does not appear to have triggered any changes in the current activity.

:)

Edited by Viking141
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Posted
  • Location: Lindum Colonia
  • Location: Lindum Colonia
Currently, St Helens is undergoing fairly regular Magnitude 1.5 - 2.5 earthquakes, however, yesterday at 2145 UTC there was a larger Magnitude 2.9 earthquake although this does not appear to have triggered any changes in the current activity.

:D

Thanks for that :)

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Posted
  • Location: Lower Brynamman, nr Ammanford, 160-170m a.s.l.
  • Location: Lower Brynamman, nr Ammanford, 160-170m a.s.l.

Thanks Viking.

Hi Flaggy

According to USGS the rate of growth of the new lava dome is currently slightly less than 1 cubic metre per second.

Hi CR

It probably collapsed which is something that happens regularly. The lava dome extrudes a slab or spine which then collapses under its own weight and wthe whole process begins over again.

Update - the slab you are referring to started to crumble in June 2006 and produced several rockfalls.

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Karangetang (Indonesia) - New Activity

Latest reports from the Darwin VAAC suggest renewed eruptive activity from one of Indonesias most active volcanos, Karangetang.

The latest Volcanic Ash Advisory timed at 0035 UTC 25th November states an eruptive ash column was observed up to heights of 10,000 ft or more. The volcano is currenly at Alert Code ORANGE.

Karangetang lies in the Sanghie Islands to the North of Sulawesi and has erupted frequently in recent times. These eruptions, like most of Indonesias volcanos, tend to be explosive in nature producing lahars and pyroclastic flows.

One to keep an eye on and hopefully I will be able to update you with further information later.

Popocatapetl

Nice picture of Mexicos most famous volcano, Popocatapetl, taken 24th November. Photo courtesy CENAPRED.

post-4448-1164559148.jpg

Edited by Viking141
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Further activity at Barren Island

There continues to be reports from the Darwin VAAC of a thin ash plume rising from Barren Island. Latest report timed at 2321 UTC yesterday identified a thin ash plume on the satellite picture. This is the second recent report of ash plumes from this volcano and could indicate she is about to fire up again. Could be worth keeping an eyeon. Barren Island lies in the Andaman Island chain in the Indian Ocean.

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