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Snipper

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    Introducing Marsili SeaMount

    in Space, Science & nature

    Posted

    7 minutes ago, BrickFielder said:

    Introduction
    My intention is to produce a series of articles (depending on interest) which introduces ideas about volcanic and earthquake activity. I want to go slightly off the beaten track to explore oddities, volcano hazards, analysis methods, Wonders and Mankind’s impacts. Keep in mind I am not expert (corrections gratefully received), but hopefully these will at least give a flavour of some different places in the world and provide a few minutes escape from people’s troubles.

    Introducing Volcano Marsili SeaMount

    547425343_MarsiliSeamount.thumb.gif.c4d88af11209bb714546fb3e545cf9cc.gifmp07.thumb.jpg.f536e9ee858b74ba0f7640bd427e59d7.jpg

     


    The Reason for Interest
    When we think about very large volcanoes in Europe we tend to think of Mount Etna yet there are some even larger little known submerged volcanoes. If one of those Volcanoes is a rather crumbling volcano which could have a flank collapse and produce a tsunami in the Mediterranean then this elevates the volcano to a more interesting one. This will be a slightly shorter post due to limited information being available.

    The Setting
     The African plate is on a collision course with the European Plate creating a subduction zone in the western Mediterranean. Over time Africa has moved so far north that almost all of the heavier oceanic crust between the continents has been subducted underneath the European plate. With Africa’s continental crust just not being heavy enough to subduct anymore the subduction has slowed and in some areas reversed.

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    What we are left with at present is a result of very complex subduction systems and rifting processes. In the SE part of the Tyrrhenian Sea the bending and stretching crust produced several basins. The rapid sinking of the Marsili Basin due to stretching was accompanied by rigorous magmatic activity from numerous volcanoes. In the Marsili basin reside at least two active submarine volcanoes the Marsili and Palinuro Seamounts. The older Palinuro Seamounts topology in its western part suggests a caldera-forming gravitational collapse event of the edifice has occurred. 

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    The Volcano
    This seamount was discovered during the 1920s and named after an Italian geologist, Luigi Ferdinando Marsili. Extensive studies have been carried out since 2005 when the Italian National Research Council started a vulcanology research program on the site. It is the largest volcanic edifice in the Tyrrhenian Sea, and it can also be ranked as the largest in Europe. The huge massif is about 55 km long and 30 km wide. The foot of the volcano is at a depth of 3000 m and it rises to some 500 m below the water surface. Marsili formed by passive magma ascent along existing fractures caused by early spreading activity. Analyses of Marsili basalts suggest the presence of a still active magma reservoir roughly 2.5 km below the summit of the volcano. Various seismographs positioned on the volcano have detected continuous shallow volcano-tectonic seismic activity.

    Recent Activity
    The most recent known eruptions of Marsili date back to an age between 7,000 and 2,000 years ago. These were events with a low VEI, occurring particularly in the central sector of the massif between 800 and 1000 m of depth. In the case of a submarine eruption at depths of 500-1000 meters, the only signs on the surface would be pumice floaters, a colored stain and spots of boiling water due to degassing. 

    Discussion
     The volcano is mechanically stabilized by a series of fractures filled with compact lava rock forming containment walls. Research vessels found evidence of many small, localized landslide scars along its flanks. Such landslides reducing the flanks are very common in submarine structures but might have reduced the thickness of those containing walls. It is thought that an inflation from the ascent of a quantity of magma could seriously destabilize whole sectors of the volcano. Tsunamis, caused by submarine landslides could extend to all the Tyrrhenian coasts including the shores of Campania, Calabria and Sicily. Evidence suggests that similar Tsunamis have happened several times in the past.  Whilst the threat is clear we should be careful not to over emphasize it.

    marsili.thumb.jpg.e49c3de34a90086e4e29290796ee8d13.jpg

     

     

     

    All good by me. Amazing what is going on there. 

    South East, London and East Anglia regional discussion - 8th February onwards

    in Regional

    Posted

    28 minutes ago, minus10 said:

    Hi Snipper. Your lunch sounds delicious!. Re plum blossoms. If the blossom hasnt opened yet then they may excape the worst of the frost. However it sounds they will be out fully soon. A tip is to give them a light hosing in the evening if you can before the night frost. The theory is the water in the flower freezes and protects the inner flower from damage by the frost. May not be 100% effective but is definately worth a try. Have a lovely day and enjoy your lunch

    Lunch was delicious. Plenty of left over stuff. Always a challenge to try and see how many meals to get out of a joint/bird.  Apart from the bones and perhaps a little bit of skin nothing will be chucked. 
     

    Thanks.  Can but try, as far as possible, keeping the frost at bay. If it isn’t the frost it’s the birds. The joys of trying to be a gardener?

    South East, London and East Anglia regional discussion - 8th February onwards

    in Regional

    Posted

    8 minutes ago, suffolk lady said:

    quick update just taken recycling out and its really chilly in the shade, nice to know you cook snipper as im very uncoordinated my hubby does all of the hot cooking he has a problem similar to yours enlarged but no big c , since last august has had permanent catheter but no surgery in sight yet he does well but gets tired easily and frustrated that he cant be as active doing diy gardening etc like he used to do, think saying for today is isnt life grand if you dont weaken, have a lovely day everyone and especially snipper and family

    Yes frustrating when you get to an age that things are less than easy.

    Had the joy of a hemicolectomy in 2012 with an encore of a radical prostatectomy in 2013. But following that the PSA reading gradually crept up. Elected to have radiotherapy in 2019. Seems to have sorted the problem so far as last test a few weeks ago showed for all practice purposes the PSA  reading as nil. Collateral damage yes but you try and work round it. Difficult on occasions not to let life grind you down. A lot if oh Sid it in our household. Hope all goes well with you and yours. 
     

    Fortunately my family is all well. My son and family ended up buying my mum’s cottage in Southwold so they are really enjoying themselves.  Lots of nice photos today. 

    South East, London and East Anglia regional discussion - 8th February onwards

    in Regional

    Posted

    Hope everyone is/has enjoyed the nice weather.  Feel I have achieved something by cutting the grass, tidying up and generally fiddling around doing stuff in the garden.

    Last thing I want is cold weather and frosts. Plum blossom just coming out, which will be trashed. Asparagus just beginning to poke through. Plenty of seedlings in the greenhouse. Lovely time of the year when the weather is nice. 
     

    I am in charge of lunch today. Well I usually do the roasts and similar. So something easy to pop in the oven that can lurk so I don’t have to check it much. Pot roast chicken with wine and herbs seems to be coming on nicely. Now need to cut some purple sprouting broccoli and get roasties ready. Should all fit in nicely with a beer or two or wine. 

    • Like 1

    Australian Weather

    in Weather Around The World

    Posted

    10 hours ago, Jo Farrow said:

    Quite incredible extreme weather for eastern Australia. And back 18 months - 12 months the same areas were hit by drought then bushfires in the hottest/driest year on record for the country. Climate Crisis.

    BoM explained that there was a tropical low over northern WA, the trough near eastern Oz then warm tropical air pulled down from the north and everything was stuck due to a blocking high over Tasman Sea (Tasmania to NZ) After nearly a week of heavy rain and terrible flooding with inland areas looking like a large lake, a coastal low developed Monday and that has brought another 100-200mm of rain to S.QLD, NSW including Gt. Sydney and VIC and Tasmania now being warned of Heavy Rain and stormy conditions as the low finally pulls away from QLD/NSW midweek.  More 

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    favicon.ico Australian floods: More heavy rain for east coast as evacuations continue

    WWW.NETWEATHER.TV
    Australia - New South Wales and southern Queensland have seen torrential rain, over 900mm this week. Disasterous flooding and yet more rain with damaging winds up until midweek.

    Extreme Daily rainfall   550.0mm    17th March 2021Byfield Childs Road QLD

    Past week's 922mm in NSW top value for rainfall

     

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    With all bush fires I wonder if erosion might be more than otherwise due to lack of binding together by plant growth. 

    South East, London and East Anglia regional discussion - 8th February onwards

    in Regional

    Posted

    2 hours ago, Blazerblue said:

    Blimey its dead in here, everyone must be out in the lovely sunny weather? Been great here today, sunshine from the word go, long may it last.

    Yep been out. Agree lovely day. Only downside was I had the task of interring my mother’s ashes in her parents grave. She had a non attendance cremation back last April. Since then she had been sitting on a shelf at the undertakers.
     

    Because of Covid not really feasible to get the rest of the family there for the internment. So did it on my own. 
     

    Lovely little grave yard.  Very tranquil with birds tweeting and a good show of daffodils. My ancestors have been planted around the graveyard for hundreds of years. If you have to end up somewhere like that it is lovely. 

    • Like 1

    Solar and Aurora Activity Chat

    in Space, Science & nature

    Posted

    6 hours ago, JeffC said:

    Observed Flux Density 74.8

    Adjusted Flux Density  74.0 = low

    Been wondering about this thread. Read for a while from the start but for the uninitiated the football score reporting of many of the posts with no comment or observation makes it rather obscure concerning what is going on. Is it possible for someone to give an updated review concerning what is going on and potential both good and bad in the future. 

    • Like 1

    Arctic Refreeze Season: 2020/21

    in Climate Change

    Posted

    8 minutes ago, BornFromTheVoid said:

    Latest I heard (a few years back) in terms of climate models was an estimate of about 2035, though most models still predict mid-century. Climate models have really struggled to accurately capture the rate of Arctic sea ice loss so it's generally acknowledged that getting below 1 million km2 (the cut off for ice-free) could happen much sooner.

    Think one certainty is any model is usually wrong.  So just a best guess scenario. 

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