CWU's Nick Zentner from his home in Ellensburg, Washington on Wednesday, April 1, 2020 during the global coronavirus pandemic. 0:00 Livestream Starts 9:57 Lecture Begins.
FUN FACT: The town of Boring in Oregon, which you touched on in this video, is twinned with a village near Perth in Scotland called Dull, and a local government area in Australia called Bland! Collectively, they're known as the 'League of Extraordinary Communities'.
My parents were climbing Mt. Rainier when Mt. St. Helens exploded. Fortunately for them, they had their skis on their backs, so as soon as they saw the eruption and that the cloud was coming their way, they put on their skis and skied down to the parking lot. Their car was covered in ash, and mom took a picture of the car with Mt. St. Helens, 5-18-80, written on the windshield (which I still have). They had a difficult time driving down the mountain and were only able to get safely down by following the tail lights of the car in front of them. By the time they got to Longmire, it was as dark as night. So I guess you could say that they were technically survivors of the eruption.
What's a VEI 6? Simple: Pinatubo in 1991 was a VEI 6, as were Novarupta in 1912 and Krakatoa in 1883. They tend to happen two or three times a century. Formally it's an eruption with over 10 cubic kilometres and less than 100 cubic kilometres of dense rock equivalent material released. Rainier does not have a VEI 6 eruption that has been found. There are a number of Cascades centres with VEI 6 or VEI 7 eruptions confirmed. Mount St Helens is one of those as it had a VEI 6 just under 4000 years ago. Crater Lake was a VEI 7 but Mazama had a VEI 6 a few hundred years before that as well.
A couple of years back, I found an unusual rock. I thought it had fossilized grass blades in it. As it turns out, it is basalt porphyrite. Thanks to your lessons and my new found passion, I was able to figure it out. It's a really cool rock, about 8" long, rather smooth, green in color with long white crystals. It looks just like one I found online from The Isle of Mull, Scotland. Thank you.
🤣 Kitty says “no”! Your girl is so sassy, I love her! Thank you for another wonderful lecture “From Home”. I’m hoping to catch you live on my day off, but watching afterwards is just fine. It gives me something to look forward to when I get home.
I can help with the Mt. Mcloughlin thing. I live close by. From what I gather it should indeed be on the maps. It is a typical composite Cascade volcano and is relatively young at less than half a million years old. The last eruption was around 20,000 years ago. However, I can't seem to find any information on the state of the magma chamber. I assume it is still very much active but in a quiet phase. Great day hike to the summit if you ever want to check out some fulgurites. Thielsen is actually a shield volcano (so is Medicine Lake) which has been glacially carved into a prominent peak. You can do Thielsen in a day too but the last 80 feet are kind of sketchy. One of the AWESOME things about climbing Thielsen is that its the only place outside of Crater Lake National Park where you can stand and see the water of Crater Lake.
I wonder if there is a video showing acres of pumice in the middle of the ocean...where people knew there was a volcano somewhere.. but all they found was floating pumice... (seems to me it was the middle of the pacific somewhere...)
min 1:02:59 erik's question about why different volcanos, I believe is related to the story of exotic terranes and the interaction with the magma coming from below...
Nick, I enjoy your talks. give me insight to my dad I did not have. I dont comment or ask questions because I just dont feel right. Knowing things, with the quakes caused from the stress release at the edge of the 2 plate, it doesn't much brain to realize a 9.+ quake it at the ever edge is not going to restart volcanoes way inland. They would need new lava feed to restart them. When the heat source is cut off from deep inside, there no way to restart them. once that happen they go dead.
I got my sample of Mt St Helen ash from a truck tarp that was covering a load of 'Kiln Dry' lumber going south of the border. I still have it in a little plastic pill bottle. I bet there are more than a few just like it.
Yup.... a friend sent me a pill bottle of ash right after the blast. I was very happy to get it. I was out on Mt Rainier July 4 1979, so I missed St Helens blast by 10 months. I love geology!!! Happy to sit in on Nick's classes. Stay safe.
After the Boxing Day quake of Sumatra, 3 volcanoes were monitored over the months after in view of the possibility of deformation of the magmachamber, they were right to. Sinabung hadn't shown any activity since 1600, she has been active since the quake. Regarding wither a volcano is dormant or not? Chaiten in Chile erupted a few years ago after a period of non-activity of 9600 years. Shasta, I believe last erupted in 1780.
Love that you're doing this, unfortunately I've tried the live stream a few times and with no WiFi up here in the mountains it lags badly, so I gotta catch then afterwards. But you casually mentioned saving a lecture for the fall, do you have a schedule set for when the current madness ends? I'm currently (sorta) relocating to Port Angeles and would enjoy a trip to Ellensburg with the Mrs to catch a lecture. Stay safe and cheers 🍻
Which is my favorite Cascade? Do I have to be specific? Although I'mpartial to: Rainier, St Helens, Hood, Adams, Mazama, Shasta, Bachelor, 3 Sisters (Bachelor and the 3 sisters were the first ones I ever saw back in 1964), and............... you get the idea. ALL OF THEM. I have friends in Vancouver WA, and I've seen the barrels of ash storedin the garage. But what's funny is, my sister-ini-law's parents in Bozeman MT had ash on their front walk.
Per wiki...Mt McGloughlin underwent three major eruptive periods before its last activity took place between 30,000 and 20,000 years ago. It is not currently monitored for activity or deformation. So.. one might assume it is possibly alive, but only sleeping.. but may be no longer even snoring...
1:14:43 I would love to watch this lecture, unfortunately can't find it on RU-vid. You mentioned earlier in the stream that it would be on RU-vid but I can't find it.
I would think that to find the answer to why certain volcanos erupt would be by doing core samples of the earth way below the mountains and near to the plate to see which kinds of rocks and minerals are softer than others which would mean that the energy from the plate could more easier move up to a particular mountain/volcano.
Hi Nick I am doing a bit of a review today and was wondering about hot springs in the state of Washington when you mentioned Garibaldi [and Mt Meagher, I reckon too] ... I was wondering about a relationship concerning Mt Meagher and Mt Baker specifically and the 'valley[s]' that connect them kind of. there are at least 4 hot springs that I know of.
A fair fraction of the 1980 fatalities were as much a product of blast effect as incandescent gas. Before a given section of the Juan de Fuca plate began subducting, it was seafloor of a given composition, which absorbed X amount of sea water. As that section of seafloor subducted and reached "melting depth" it was under a corresponding area of North American plate, with its own unique composition, which varies, with depth and liquid content, layer by later, all the way to the surface. Magma doesn't form at depth and squirt or get forced to the surface, per se. Instead it melts rock around and above it, and the heat energy is the only certain transported variable by the time it surfaces, if it ever does. So "today's hot volcano" would be a product of time, the materials in both plates, water content, localized pressure regimes, where the rising blobs just happen to be most numerous. Are there even discrete magma conduits andchambers? Yes, in the shorter term, as pressure will vent via the easiest escape path, but long term, these aren't given.
As far as a link between a major earthquake in the subduction zone and eruptions I think the earthquake has an effect on the magma bodies. However due to the variability in the rock and magma bodies combined with the time scale a link would be nearly impossible to prove.
