So I’m back after a nasty hard disk failure, sorry for the absence, but a six year old Mac Mini can be a testy machine at times. These things happen.
Word has it that Katla is working up to an eruption, and may have already produced a sub-glacial eruption during the summer. Seismic activity at Katla seems to have been on the rise of late, spiking significantly over the last two days.
Of course a major eruption of Katla poses the risk of lahars and flooding (because it’s covered with a glacier), as well as ash hazards to air traffic, but we don’t know that it will erupt, or if it does how big an eruption it will be. It’s just showing signs that it might be getting ready to erupt. Unfortunately the KatlaCam is down again this morning, so we can’t catch it in the act if it does erupt.
Katla has a far bigger magma chamber than does Eyjafjallajökull (which I can’t pronounce either) I’m told it’s magma chamber is ten times the size. Iceland’s volcanoes are capable of some pretty serious eruptions, the worst of them in historic times being the 1783 Fires of Skaftá at Lakagígar which lasted two years and killed a quarter of Iceland’s population by means of indirect effects. That eruption is said to have erupted the largest quantity of lava from a single eruption in historic times.
While Katla threatens to erupt Krakatau has just gone ahead and done it, not messing around in the least. Those monitoring the volcano have recorded between 6000 and 7000 volcanic quakes per day since the weekend, a big jump over the normal 200 or so, which has inspired officials there to declare a 2km exclusion zone around the volcano, and advising that no one climb up to the crater to look in, which seems a no-brainer to me.
Krakatau seems to be entering a new eruptive phase and scientists there are trying to figure out the type and potential scale of the eruption. Given the drastic increase in volcanic quakes under the mountain it would indeed seem that it is entering a new eruptive phase in it’s pyroclastic cone-building stage.
This latest eruption produced an ash column of about 3000 ft., larger than it’s eruptions of previous years, and following a huge increase in seismic activity but this should not be taken to mean a major eruption is on the way.
Merapi produced an enormous eruption even when it’s seismic activity was quite low, and so that cannot be taken as an indicator of the scale of an impending eruption.
You may note that I do not refer to this volcano as “Anak” Krakatau, and that is because I do not regard it as the “child” of Krakatau. To me it’s Krakatau, plain and simple. Same magma chamber, same vent, new cone is all. It’s Krakatau’s newest incarnation, and I expect that it will in time go the way of all previous incarnations of Krakatau.
That is to say it will at some point produce another cataclysmic eruption and blow itself to bits, spreading destruction around the Sunda strait once again as it has done repeatedly in the past. I don’t expect this to happen anytime soon, but after it has built itself up to something like it’s previous size, perhaps creating another volcanic complex having multiple vents. Krakatau is known to have erupted in 416 AD, and again in 535 AD. So I have to think that sometime in the next 250 years or so it will repeat it’s 1883 performance.
Sheveluch has erupted again, producing an 8-10km ash cloud. No on is in danger from the eruption and no ashfall has been reported in the surrounding settlements. Sheveluch last erupted in May of 2009 and has been continually degassing and oozing lava since. Satellites observations have detected a “thermal anomaly” and a brightly incandescent lava dome.
Active Volcano Working Group:
Whilst digging around the web for news of the world’s volcanoes I came across a couple who are in love with volcanoes and spend their time photographing active volcanoes. Remind you of anyone?
Donna and Steve O’Meara are the happy couple, and they certainly do remind me of Maurice and Katia Krafft. I fervently hope they do not meet the same fate, and wish them all the best in their pursuit. Back in 1973 I was at Kilauea, and looking at something very much like this, from about the same distance as Steve is from here on the right.
It gets pretty hot there in places. When I was there back then there was a lodge overlooking the volcano, which it has since consumed. Donna and Steve have taken some marvelous photos of volcanoes, and like the Kraffts have undertaken the mission of saving the lives of those living close to volcanoes.
Steve has a theory that volcanic eruptions can be predicted using the cycle of the moon, and plans to create color coded calendars for high and low volcanic activity. I’m not sure how that will work out, but it sounds like an interesting theory. I’ll see if I can figure out the moon cycle for some recorded eruptions and see if there might be anything to that. August 27th 1883 might be a good date to start with.
Like the Kraffts the O’meara’s are acutely aware of the dangers of what they are doing. Says Steve, “It is dangerous and we are always cautious, you have to be — one moment of stupidity could cost you your life.”
Well you don’t even have to be stupid. Volcanoes are notoriously unpredictable, and even the best laid plans can have fatal results. Again, I wish these two the very best of luck and pray for their safety.