Just wanted to point out that depending on the metric you use, Mauna Loa is even taller than is commonly thought. While the peak is 4,170 m (13,680 ft) above sea level, and the base meets the seafloor at around 5,000 m (16,400 ft) below sea level, for a total relief of 9,170 m (30,080 ft), the actual total relief of the volcanic pile is much higher, because the thin oceanic crust onto which it has erupted is depressed by the extreme mass of all of that heavy volcanic rock, and this subsidence is most extreme in the center of the volcanic edifice. In fact, according to the USGS, the center of Mauna Loa depresses the oceanic crust an additional 8,000 m (26,250 ft). In cross-section, the volcanic pile resembles a “lens” shape, where the dome of the shield volcano above the crust bows upward, while simultaneously bowing the crust below it downwards into a bowl shape. Thus the total relief of Mauna Loa is an incredible 17,170 m (56,330 ft), or nearly twice the height of Mt. Everest! You may think, “this is unfair, we don’t measure the base of mountains like Everest beneath ground level, surely they also depress the crust.” Here’s the thing-normal mountains don’t. The reason is, when mountains are built during orogenic events, the entire crust is thickened. This crust, being lighter than the mantle, floats on the mantle below it, much like an iceberg, finding its level of neutral buoyancy, the portion “above”, being propped up by an even more massive portion “below”. We don’t count the thickened crust below a mountain as part of its height, just like we don’t count the thickness of the oceanic crust below Mauna Loa. Mauna Loa is different than relief formed through orogeny, because it is a pile of volcanic rock. The eruption of all of this volcanic rock doesn’t create anything like a the “orogenic” root below the Himalayas (though a small portion may be “underplated” in the form of mafic igneous complexes/cumulate complexes), nearly all of that volcanic rock is erupted above the original oceanic crust, which is why it is able to be depressed to such extremes. Mt. Everest doesn’t depress the crust below it, precisely because it has an orogenic root that keeps it propped up in the mantle. Because of this, we can measure the entire height of the volcanic pile of Mauna Loa, from its most depressed point in the center, to its peak, which gives us that much higher figure than simply measuring the relief of the peak to where its furthest extents reach the seafloor.
Excellent explanation Avana.👌 I live approximately 35 miles from the Mauna Loa summit and watched the beginning of the eruption at 11:30 pm Sunday night. Most people use the 30,000 ft description without any reference to the 26,000 ft channel around the base of the sea floor. Many of the earthquakes we feel are the result of the mountain settling into the sea floor or mantle surface. The sheer volcanic mass of the mountain is actually displacing magmug under the sea floor at a rate relatively near equal to the weight of material above the ocean surface and equalizing in equal portions as the mass is spread out below the ocean's surface until the mass contacts the sea floor. Not being a geologist myself, I do not have all of the proper terms to describe this phenomenon, but as a lover of science I understand the dynamic principles in play. The whole process is quite fascinating for sure.🤙
@@gwbuilder5779 Wow! That must be something. The photos of the sky looked amazing, but I imagine in person it must have been much more incredible. Hopefully it stays restricted to the highest heights and doesn’t threaten anybody. And hopefully the government doesn’t try to bomb it like they did in 1935! 😂 The higher measurement is just another way of measuring. I personally like it because otherwise one ignores the massive amount to which the mountain actually affects its surrounding area, and disregards a huge volume of volcanic material. Actually a similar thing happens at continental stratovolcanoes and volcanic arcs, like Mt. Rainier and the Cascades. There, the weight of the volcanic edifices causes an “axial graben” to form along the arc, where the stratovolcanoes themselves commonly sit in a sunken trough. Gravitational spreading also occurs in these settings (Mt. Etna is a great example). So I suppose one could measure these stratovolcanoes’ heights starting from the base of their axial grabens-in practice, no one really does this, though. You’re absolutely right about those EQs and the slipping. As I understand, because all that lava erupted onto seafloor, which is covered by slippery oceanic sediments (albeit relatively thin, given the low levels of sedimentation in the middle of an ocean basin), as the volcanic edifice spreads gravitationally under its own weight, a décollement, or subhorizontal fault/slip surface has formed at the interface between the volcanic pile and the sediments, and that is responsible for some of those earthquakes. Stay safe and enjoy the show!
@@AvanaVana The show is gone here. I'm in the South West rift area, so as the summit activity has diminished and moved further North East, the show has dropped below the summit. Tonight there is no color in the sky at all which is crazy, but makes perfect sense. I am guessing that the initial fountains Sunday night probably went as high as 2,000 ft judging by the amount of spatter debris and how far away from the fountains it is. Those first 30 minutes were quite spectacular and very bright yellow/orange versus the more common red/orange/pink/purple throughout the rest of the eruption. Tonight, there is a slight pink/purple/orange thin outline on the silhouette of the summit almost like the last colors of a faded sunset. The good news is no threat of lava flows this direction for now. Of course volcanic eruptions are completely unpredictable when it comes to determining surface ruptures, so wait and see is always the way we live. Thanks for the conversation, not too many people talk to me about things like this because they don't relate, but I understand. Thanks again.🤙
Hi Myron. In 1980 I was sitting on top of Haleakala on the island of Maui at about midnight when the volcano Kilauea started to erupting for the first time on the Big Island. I stayed up till 4 am watching it unfold. It is still erupting to this day. Will never forget it.
Great discussion as always, Professor Cook. Thanks so much this short but highly insightful lecture on volcanoes, plate tectonics, and subduction in the infamous Ring of Fire. You are far beyond brilliant!👍🏼🤝🏼
Lohi went off 3 hours before Mauna Loa so the flow came from the main chamber of the Hotspot rather than a magma pocket floating upwards. Yellowstone has a magma pocket floating up in the North East corner that's detached from the main magma chamber. Pockets of magma are still floating up in Haleakala in Maui that are distanced away from the main chamber. They recently even found a hot spring in Kaui and they thought it was extinct. The hot spot trails under all the islands but the main chamber thankfully is under the East coast of the Big Island, looks like she's tapping it.
What is the source of “Loihi went off 3 hours before Mauna Loa“? Do you mean there was an underwater eruption on the seamount? The last update by the Hawaii volcanoes observatory on Loihi was November 3. No significant activity was noted.
@@aey808 there is a single RU-vid video claiming that a heat signature was detected by a GOES sat. 3 hours before in the area of Loihi. The validity of the claim made in the video is questionable.
Listening to you explain all of the nuances of geology and how our planet is shaped by the forces at work that make these changes over time is just fascinating to learn about. You are a natural speaker who knows very well what you talk about, and I’m grateful to have found your RU-vid channel! Thank you for your expertise in this area and I look forward to seeing your other videos as well. ❤
Oh my God this man is so awesome and I learned so much about volcanoes tectonic plates and how everything works, he explains it so damn well it's ridiculous I love him!
Great video Myron. I've always hoped to see Mauna Loa erupt since I was a kid. My family would always vacation in Kona every year and I was always so interested in the volcanoes on the island. I've been following updates on Mauna Loa since 2019 when activity started to uptick. I was very surprised to see the news of the eruption because there wasn't much warning. Anyways great content as always Myron.
Thank You, Myron! I'm enjoying my chill Sunday morning with random selection of your videos. (And, oc various channels updates from Icelands ongoing eruption!) Greetings from Värmland county, Sweden 🙌🏼
Thank You Myron.... I was very busy doing something else important. When I saw your newest broadcast I stopped what I was doing & watched!!!!!!! 🙂..... TM
Was excited to hear about Mauna Loa and nearly as excited when I saw you had released a video on it. Now off to watch more videos on atolls. Thanks, Professor!
I love the way you spell it all out. You come down to the layman's level, and speak with a calm, soothing voice. I did know about the seamount chain and plate tectonics because I watch Nick Zentner a lot. I learn a lot fom watching him too.
Dutchsinse channel discusses the 'seamount chanin' as well. he's posting just about daily now. Also check Dutchsinse recent post re: Lohi seamount (just off Hawaii) erruption 3hrs BEFORE Mauna Loa
Wonderful teaching video form a USGS Geologist who has a wonderful talent for bringing parts of the life cycle of a Volcano to where it si interesting and very revealing.
Thanks for another amazing presentation. The sea mounts and tectonics are an exciting revelation to me. Also the height from the sea floor of the Mauna Loa mountain.
Thank you Mr. Cook. Great explanation in simple terms. I've been watching as the last time she erupted, I was at Hickam AFB on Oahu, and my youngest daughter is now stationed at USCG Honolulu. Truly impressive in its beauty.
I could listen to you and talk with you for hours on the geological subjects. I can see the passion you have and wonder in your eyes for this fields of science. It is so amazing how we take for grant the land we walk on. It is constantly moving...albeit very slow for us but fast for the geological clock. Only time we ever see a major land shift quickly is of course volcanoes and earth quakes. I never knew the islands of the pacific were moving north....if we had a device that allowed us to actually watch the movement (not computer generated) and see the final position of the main Hawaiian island after 100 million years in a few seconds how amazing that would be. Thank you for making and sharing your videos.
I really appreciate your information. We’re on Hawaii Island experiencing this. We experienced the Kilauea eruption in 2018. Thanks for elaborating on the process. We just tend to hope for the best.We do pay attention to information from the USGS.
I am very happy to have found this channel. We are interested in geology and what's more you are in the area that we spend a lot of time in, Wyoming. Unlike that other well known channel which mainly is in the NW. And you are doing field demos too. Could not ask for more. Keep up the good work.
I love your videos .they are so well presented. I'm learning so much watching them. The places you're visiting are just spectacular.. Thank you for sharing..
I love this! Back in the 80s and 90s, my family lived in Micronesia (Pohnpei and Palau) and it’s because of this, island formation fascinates me! We also lived in the Sierra Nevada, Bryce Canyon and other places because my father was a rolling stone. Plus, living all those places has giving me an appreciation of the diverse geological features here on Earth. I’m so glad you explained how atolls and barrier reefs form because not too many people are aware of those geological features. I was fortunate to talk a specialized college level marine biology class as a high schooler and there was a lot of focus on island creation. I may have tuned out for a moment as I started to formulate my comment (ADD), but did you mention there will be a new Hawaiian Island soon; that is to say, in geological time? Loihi is the name and I’m sure someone has pointed this out already, so forgive the redundancy if they have. But as always, thanks for the videos and explanations as a geologist. It’s a joy to learn from a scientist how these features were formed!
Wow, what an experience living those places must have been. I actually only heard about Pohnpei for the first time yesterday when I came across an article on Pohnpeian language…and funny enough, here’s someone who lived there. :)
@@AvanaVana Ha! Isn’t I funny when that happens? Palau is much more popular because it’s famous for its diving, but Pohnpei is definitely worth a visit! But I’m intrigued at your process of stumbling across Pohnpei by searching languages? Most people just want to escape to a remote tropical paradise!
I find it amazing that the "Hot Spot" remains stationary as the Pacific Plate is relentlessly moving across it to the northwest! It is also incredible that the Hawaii Hot Spot has existed since the Cretaceous, if not longer. The idea that it has been in constant existence pouring out lava for at least 70 million years is simply mind-boggling!
Son of a gun, Profesor, you did it again! EXCEPTIONAL presentation and absolutely fascinating visual aid on how the chain of islands have come to be! You are truly a gift to us all non-geologists type. Thank you, Professor, for taking your time to set up and provide this invaluable knowledge.
Prof. Cook thank you so much for this explanation it ties very closely with a public lecture series on Baja-BC currently put on by Prof. Nick Zentner also available on YT.
I'd looked for some information about this eruption, and your explanation was by far the best I've seen. I got a decent picture from the USGS scientist, but he used a lot of jargon I'm not familiar with. The Google Earth model and even the dry erase board model were quite helpful in understanding these processes. I feel I could even show these to my young sons to help them understand. Excellent video & you've earned a subscription from me!
Thanks for the update professor I’ve been trying to stay on top of this because it could lead to bigger eruptions seeing there all connected together when one goes it’s a matter of time before the others go as well because of ground movements and lava flow under the ground that your can’t see and it’s also on a fault line
Myron I'm so glad I found your channel. I'm a former geoscience teacher and usgs retiree. I am disabled and cannot get into the Backcountry, so your videos takee along. I find your abilities to see the whole picture and relate it to viewers fantastic. I have always been a big picture person with strong feelings of my place in the universe. I don't find very many people have a perspective like yours and mine. I am very glad you share that with people and hopefully more people see the big setup and how all things work together in our natural world. Great insight is a gift. Thanks
For this interesting and simple to understand information. I added this to my volcano playlist. I'm posting it in some earthquake and volcano groups as well as Grand solar minimum groups. Thank you
as a Marine, i spent time on the islands... never really appreciated them and just wanted off of them... but with this kind of explanation of them... well, now, i want to go back and study them ... thank you for giving the insight
