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id02009 t1_j9zi7rp wrote

Reply to comment by CrustalTrudger in When a volcano erupts, does this affect the pressure building up in other volcanoes? by Rhamni

Follow up: how do we know those volcanoes in Hawaii are vents from the same system? Are we sure, or is it an educated guess because they're close enough?

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Uncynical_Diogenes t1_j9zm926 wrote

>same system

These systems are much, much bigger than you’re thinking of.

The Hawaiian islands are volcanic islands created by the same “hotspot” plume in the mantle as the overlying plate moved over it. They were created in sequence by volcanic eruptions from that same upwelling. It makes perfect sense for all the islands to be related, so for multiple volcanoes on one island to be related is a no-brainer.

The matching mineral composition and timing of those eruptions indicate they are related. Kīlauea and Mauna Loa’s eruptions are linked to decreases in the other’s activity for a while. Given all the evidence, there’s no need to guess; the volcanoes that make up the island of Hawai’i are linked. It would be far more difficult to adequately explain how they weren’t, if that were true.

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Ieatadapoopoo t1_j9zob38 wrote

I’m sorry, I’m not trying to be pedantic, just making sure I understand, but it does sound like an educated guess, no? An insanely solid goes off course, but it sounds like we’re just really really certain of our guess. That’s enough to convince me, just wanted to be sure I had it right!

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CrustalTrudger t1_j9zx3vl wrote

While not as unique as fingerprints, individual magmatic systems tend to have somewhat individualized geochemical profiles in terms of concentrations of trace elements and isotopic ratios so it's not "guessing" to use similarities of geochemistry to argue that two adjacent volcanoes share a source and/or have intermingling of sources in the shallow crust. Additionally, there are variety of geophysical techniques (seismic tomography, magnetotellurics, resistivity, etc) that allow us to image the magmatic systems of volcanoes which again provide evidence that these are related. The general idea that geology is all "educated guessing" (which underlies many questions and lay answers/comments in this subreddit) is pretty frustrating given the extreme care and detailed analysis many of us put into to understanding the details of natural systems.

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Ieatadapoopoo t1_ja04esr wrote

Ah, that makes sense. Thanks so much for clearing that up! I’m completely ignorant, so I had no idea what the process was like.

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imdoneanymore t1_ja09w58 wrote

You may want to read this

https://www.usgs.gov/news/volcano-watch-new-research-sheds-light-recent-pahala-earthquake-swarms

on the Pahala quakes that are happening between Mauna Loa and Kilauea. It’s all about plumbing and after ML’s recent eruption there are geologists all over the area now, because what they thought to be true is being challenged by what happened in this last eruption. It’s really interesting stuff. And a rabbit hole lol.

I live on the slopes of ML and find it fascinating.

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Ieatadapoopoo t1_ja0b8eg wrote

Thanks, I can’t wait to get a minute to dig into this :D

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JonArc t1_ja05yfh wrote

On a slightly smaller scale we've sismic imagery (think like a sonogram) of a lot of the near surface plumbing on the big island so that cover Kilauea, Manua Loa, and a few other features. If you read about the 2018 eruption of Kilauea you'll see that in action as it's all about a loss of pressure in the system.

I'd also add that the hotspot didn't just make the modern Hawaiian Islands. There's a whole chain of eroded sea mounts that used to be other islands! And the direction they go in is in the direction the Pacific plates is moving. And this is a trait we see in other hot spit volcanos. Since the souce of the heat is from the mantle it doesn't move, but the plates still move over it.

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QuiteAffable t1_ja3h7n2 wrote

For a similar example look to the hotspot that created Yellowstone park

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