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NorthNorfolkWeather

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Posts posted by NorthNorfolkWeather

    Bárðarbunga and Askja - Volcanic Activity

    in Space, Science & nature

    Posted

    This might sound like a silly question.. :cc_confused:

     

    If the magma chamber is no longer full and is emptying in to the dyke, then this would leave an empty space between the mountain and the bottom of the magma chamber, presumably filled with gas and air, so when the low pressures system forecast to hit overnight does would the presumably higher pressure inside the chamber try to adjust to the lesser outer atmospheric presser caused by the low pressure. Similar to our ears popping as we change altitude.

     

    What would the most likely affect be?

    I would think that the overall difference in pressure would be negligible compared to the pressure that's already there.  I suppose it could be the "straw that breaks the camel's back" but I doubt it

    Bárðarbunga and Askja - Volcanic Activity

    in Space, Science & nature

    Posted

    Why do you think there will be an eruption tonight?

    Probably vain wishful thinking

     

    But

     

    Many of the quakes, although small, seem to have been at less than 5 km deep, that suggests that some magma is trying to feed to the surface.  I think the biggest thing is how much gas is in the magma, if it's highly gassed then we'll have explosive decompression and that will rip the fissure.

     

    The other point that's been made is the strength of the quakes at the main Cauldera, if they have seriously weakened the surrounding geology, then either a flank collapse or a Caulera collapse coun't be ruled out

     

    There again, I could to completely wrong

    Bárðarbunga and Askja - Volcanic Activity

    in Space, Science & nature

    Posted

    how much more 5 + magnitudes can that rim withstand.  It must be seriously weakened last few days.

     

    Swebby not sure saw those earlier was quite a bit kick off earlier there was big discussion on forum if it was dust storm or it extended the rift it did look white which suggested steam melting ice

    You'll be surprised how much stress these can take, there are so many factors that can affect the system, slip angles, ice cover, wedge shape.  You could see as many as another 20 at M5, but remember that's only 8 at M5.3 or 2 at M6.  The fact that earthquakes are measured on a log scale means that an M5 releases 1,000 times the energy of an M2

    Bárðarbunga and Askja - Volcanic Activity

    in Space, Science & nature

    Posted

     

    It looks like there has been a quieter (not quiet) 8 hrs or so since mid morning, however there does appear to a certain cyclical rhythm to the earthquakes with fewer larger quakes during daylight hours (as per table below from the Icelandic Met Office website.  

     

    Although not a very relevant topic to this thread, the IMO website is an absolute pleasure with various sections aimed at different levels of reader from simple graphic overview charts, to areas that are in more technical detail, and cited extracts and links to even more specialist research materials in its various earth science topics. 

     

    I've noticed the cyclical cycle as well Tim, I was wondering about any Moon or Sun/Moon influence.

     

    As for the IMO website I agree  --  but until 4-5 years ago the IMO and the Earthquake people were separate, brought together to save money, but they have done a fantastic job

    Bárðarbunga and Askja - Volcanic Activity

    in Space, Science & nature

    Posted · Edited by NorthNorfolkWeather

    And now a huge 5.4 mag quake

    Saturday

    30.08.2014 07:03:02 64.611 -17.457 2.9 km 5.4 99.0

    4.7 km SE of Bárðarbunga

     

    The previous 4.2 was much deeper at 9.1 km.A quake over M5 at that depth (2.9km) will produce a lot of movement.  JP was talking about a flank collapse yesterday, this would suggest the east side is vulnerable, but may be held together by ice  --  until any mamga come through

     

    I see you beat me to it John (great minds --  I hope)

    • Like 1

    Bárðarbunga and Askja - Volcanic Activity

    in Space, Science & nature

    Posted

    I have given up trying to work out whats happening now

    Never seen a set up like this before

    The thing that i feel is worth watching is a collapse of some kind

    Of baroabunga. Looking at the quakes these have almost encircled it so

    The chance of a subsidence event and flank collapse must be a risk

    However again its a watch and see

    http://en.vedur.is/earthquakes-and-volcanism/articles/nr/2949

    John,

     

    Which do you think is more likely, a Flank collapse or a Cauldera collapse as a lot of magma has flowed out to the North/North East?

     

    I think the latter (Cauldera Collapse is rather more likely if it's the ring faults cracking under the strain  --  less pressure holding them up and a huge weight from the glacier pushing down.

     

    I almost prefer the idea of a flank collapse rather than the other

    Bárðarbunga and Askja - Volcanic Activity

    in Space, Science & nature

    Posted

    From that report

     

    "The eruption fissure is about 5 kilometers from the Vatnajökull glacier. The fissure appears to be about 1 kilometer long. The lava is thin and flowing quickly southeast towards the glacier."

     

    I assume that means the lava on the surface is flowing southeast?  Everything we've seen to date suggests it's moving north to North east towards Askja

    Bárðarbunga and Askja - Volcanic Activity

    in Space, Science & nature

    Posted

    I agree about the ash updates.  But they are right not to issue them if there isn't any :-)

     

    ANYTHING is better than TV.....

     

    But there again I'm working (from home thankfully) so TV is off the menu

    • Like 1

    Bárðarbunga and Askja - Volcanic Activity

    in Space, Science & nature

    Posted · Edited by NorthNorfolkWeather

    Volcanic ash advisory from teh UKMO not expecting anything for a while

     

    via twitter

    http://www.metoffice.gov.uk/aviation/vaac/vaacuk.html

     

    536
    FVXX01 EGRR 291100
    VA ADVISORY
    DTG: 20140829/1200Z
    VAAC: LONDON
    VOLCANO: BARDARBUNGA 373030
    PSN: N6453 W01650
    AREA: ICELAND
    SUMMIT ELEV: 2009M
    ADVISORY NR: 2014/003
    INFO SOURCE: ICELAND MET OFFICE
    AVIATION COLOUR CODE: ORANGE
    ERUPTION DETAILS: NO OBSERVATION OF VA IN THE ATMOSPHERE.
    OBS VA DTG: 29/1200Z
    OBS VA CLD: NO VA EXP
    FCST VA CLD +6HR: 29/1800Z NO VA EXP
    FCST VA CLD +12HR: 30/0000Z NO VA EXP
    FCST VA CLD +18HR: 30/0600Z NO VA EXP
    RMK: NO VA OBSERVED. OVERFLIGHT CONDUCTED AND NO LAVA WAS
    OBSERVED FLOWING FROM FISSURE N OF DYNGJUJOKULL. REPEAT
    NO VA OBSERVED. NO FURTHER ADVISORIES WILL BE ISSUED
    UNLESS CONDITIONS CHANGE.
    NXT ADVISORY: NO FURTHER ADVISORIES

    Bárðarbunga and Askja - Volcanic Activity

    in Space, Science & nature

    Posted · Edited by NorthNorfolkWeather

    I'm a bit confused by some conflicting reports. Does this mean that over the next few weeks a full on eruption will happen with closed airspace or that over the next few weeks it will be bubbling up for a later eruption?

    Could be either, or it could just go back to sleep.

     

    Time will tell

     

    Have the cameras gone offline?  I'm getting a "Server not found" on all the Mila cameras.

     

    Probably crashed due to people like me wanting to look.....

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