The Volcano In Pemberton's Backyard: Mt Meager

[Music] this looks like just another mountain north of pemberton at the head of the lillauet river but it's actually the site of canada's largest volcanic eruption in the past ten thousand years that's like yesterday in geological terms [Music] mount meeger is also the site of a landslide in 2010 that is estimated to be the largest of all time in canada [Music] glaciers and ice fields blanket meager just like other volcanoes you've heard of mount adams bachelor baker hood rainier and the infamous mount saint helens those are all part of the cascade volcanic ark which the garibaldi volcanic belt in bc is the northernmost part of there are six major summits of meager massif meager with plinth behind capricorn job pylon and the devastator plinth is the highest at 2680 meters the cause of these volcanoes is subduction of the juan de fuca plate under the north american plate volcanic activity is evident by the hot springs around meager of which there are at least two the water is heated by magmatic heat and it rises through faults to the surface which also hint that the shallow magma chamber is near meager has high geothermal energy resource potential although none has been developed so far we could be tapping into this renewable resource just like iceland does other clues of volcanic activity are visible at keyhole falls a lava flow came down into the valley creating a dam blocking the lillouette river here you can see columnar basalt vertical walls forming a gorge with the obvious shape of keyhole falls upstream a lake was created behind the dam and when water weakened the lava formed rock it released in an outburst flood transporting large boulders downstream for more than two kilometers water has continued wearing down through the rock giving keyhole falls its name [Music] this eruption originated from the bridge river vent a volcanic crater that formed merely 2400 years ago on the northeast side of plinth this eruption likely reached 5 on the volcanic explosivity index or vei similar in scale to mount saint helens a column of ash reached 20 kilometers high into the atmosphere with winds carrying it as far as alberta it is possible that human knowledge of the eruptions at meager in the past 10 000 years is insufficient as it hasn't been monitored closely enough which is still important today future eruption or landslide events pose a risk to people living and working in pemberton valley see the 2010 slide of capricorn creek parts of the landscape there still look like the surface of the moon 11 years later amazingly no people were killed by the 2010 slide flooding could be caused by rapid melting of glacial ice or outburst flood if a river is dammed and then suddenly releases pemberton is 50 kilometers downstream of meager but still first in line in terms of hazard scientists call meager the most unstable mountain in canada behind me is the bridge which used to span across lillewet river connecting to meager creek fsr all that slide debris washed away the bridge as you can see and lifted it and carried it all the way here so that landslide had huge power and this is uh just a small small picture of that i wanted to learn more and still had questions about volcanoes so who better to ask than a geologist my name is connor ozinga and i'm currently getting my master's degree in geology and i would say i'm a geologist so how the coast mountains have formed is there's a north american plate then there's the juan de fuca plate which is an oceanic plate yeah and that forms from mid-ocean ridge gets positive assault it's basically a new crust new land that's being formed and of course it's kilometers underwater so no one ever sees it but as the north american planet wanted food move plate subducts underneath the north american plate because it's more dense and as it subducts it will cause slight uplift which that's what we see now as the coast mountains then as also as it subducts magma will start forming from hydrous minerals within the juan de fuca plate releasing the water and causing melting to occur because water causes the melting point to lower of minerals or rocks either either or because minerals make rocks and then that mega will slowly rise to the surface and if it reaches to the surface it'll form a volcano so that's happening kilometers down yeah kilometers okay really most magma chambers are usually kilometers down but then like this will occur down in the mantle which is even farther okay yeah because that's what's directly leading to uh the reason that mount meeger's there yeah so this lava is yeah it's slowly working its way up from the mantle into the crust and eventually it's popping out from elmigress do hot springs exist elsewhere not around volcanoes oh yes a good example would be the canadian rockies there aren't any volcanoes there but there's these really deep faults so basically service water will travel down these faults get heated up really deep underground then travel back up another fault and come up to the surface and we'll be hot spring a lot of people don't know about the volcanoes that exist in canada what can you say to that yeah they're definitely not well known and i think that's because they're not as active as say mountain helens which is really active or one time this little kid fl i flew over it and there was steam coming out of it so just clearly show it it was active yeah but most canadian volcanoes haven't erupted any time recently in history like human history i should say like right yeah yeah where there'd be cameras pointing at it or helicopters flying over these are geological so like recently like say an eruption could have happened 10 000 years ago that is super recent geological and that basically still means it's active but yeah humans might have not been around to see that at that point how accurate are eruptions to predict basically how they're predicted is earthquake swarms because as the magma moves up through the crust they'll generate a bunch of earthquakes so when there's an earthquake swarm that's an indication that an eruption is going to happen of course you get earthquake swarms like months before to hours before it it ranges in a huge time scale so it's sort of it's just a waiting game once earthquakes start happening you just have to wait for it to erupt living next to a volcano is probably a risky place to choose to live what are those some of the biggest risks risks would probably biggest risks ash is a huge one especially if it gets in your lungs it can cause a bunch of issues lahars which is just mud flows that can happen especially if they're glaciated because the glaciers can melt release a huge amount of water causing muscle yeah landslides that's another one then of course the lava you've got to worry about that or if it explodes such as mountain helens causes a huge explosion to go out yeah then that can be a risk too generally the closer you are the more dangerous it is but the most widespread damage that can happen from volcano is definitely the ash because it can cover such a large area right and get lots of people long issues thanks for your time conor appreciate you talking to me glad to talk to you talk with you yeah sharing your knowledge cheers cheers jack souther was a geologist and leading figure in volcanology in western canada he said quote the flare-up of meagre mountain 2500 years ago raises the question could it happen again with the explosive eruption of beaker mountain the last gasp of the garibaldi volcanic belt or only the most recent event in its ongoing life the short answer is nobody really knows for sure [Music] so [Music] you

Channel: lifeofluke

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Length: 8min 43sec (523 seconds)

Published: Sun Dec 12 2021