5 ms·

I'm tied into many seismic sensors around the planet through Google Earth, almost all of them USGS-owned. Very little is happening around or under Mt. Adams. S

I'm tied into many seismic sensors around the planet through Google Earth, almost all of them USGS-owned. Very little is happening around or under Mt. Adams. St. Helens is seeing actual noteworthy activity, and even that's still lower than magnitude 1 in almost every event, and those that get higher than 1 99.9999% of the time do not reach magnitude 2. There isn't a huge amount to worry about from the volcanoes, unless a body of water intrudes into a magma chamber. Worry more about the Cascadia subduction zone letting a good one rip.

blackeyeblitzar 2y ago
Can an earthquake trigger a volcano?
- jajko 2y ago
  Why shouldn't it? I imagine volcanoes as evolving pressure situation slowly tipping towards eruption. Anything that disturbs situation and tips it faster towards eruption, like an earthquake seems as a reasonable assumption. Not that all earthquakes tips it towards it, sometimes maybe it actually relieves the pressure, depends how things move and crack.
- dredmorbius 2y ago
  It's possible, by several mechanisms. The Mt. Saint Helens eruption was precipitated by a landslide, which reduced pressure over the caldera, leading to a sideways-launched blowout of the volcano itself. That landslide might very well itself have been triggered by an earthquake. Other possible mechanisms would be either the widening of a magma tube or fissure (permitting higher pressures to the surface), or the introduction of water (crustal or near subsurface) to a magma tube, with the ensuing steam explosion precipitating an eruption. The role of water in vulcanism is something I'd not been aware of until relatively recently. The Ring of Fire volcanoes form largely around subduction faults, generally inland of where an oceanic plate subducts beneath a continental plate. The oceanic plate carries with it large volumes of seawater, and as that plate itself intersects with (and is absorbed into) the mantle, that incorporated water flashes to steam. The steam pressure itself then plays a major function in generating pressures and driving magma toward the surface. This is also why volcanic eruptions tend to have so much steam as part of the emergent material, so far as I understand. Another recent eruption in which water (in this case seawater) played a huge role was the 2022 Hunga Tonga–Hunga Haʻapai event, occurring as seawater flooded into a large, shallow caldera, flashing to steam with explosive consequence. Whether or not that event was preciptated by an earthquake again isn't clear, but could be possible. Other mechanisms might have been a cascading failure of the overlying roof of the caldera, with smaller introductions of water expanding access and leading to the catastrophic failure and explosion. There's some scientific research into the question: "A review framework of how earthquakes trigger volcanic eruptions" (2021) <https://www.nature.com/articles/s41467-021-21166-8 https://www.nature.com/articles/s41467-021-21166-8> "Can earthquakes trigger volcano eruptions? Here's the science." (2019) <https://www.nationalgeographic.com/science/article/can-earthquakes-trigger-volcano-eruptions-get-facts-geology https://www.nationalgeographic.com/science/article/can-earth...>
  - lazide 2y ago
    Also, “water” (quotes due to the fact it’s hard to actually call it water under these conditions) and sea floor minerals like carbonates change the actual viscosity and chemical composition of the magma in interesting ways that encourage all this too. It’s not just bulk water flashing to steam.
    - dredmorbius 2y ago
      Thanks. I should note that this is all well outside my scope of expertise. Though the raw amounts of water in subducted seafloor are apparently immense. Something which really hadn't occurred to me until recently.
      - lazide 2y ago
        Not widely known I think - here is a neat write up on it [https://repository.geologyscience.ru/bitstream/handle/123456789/37061/Mann_04.pdf?sequence=1 https://repository.geologyscience.ru/bitstream/handle/123456...] And another [https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2002GC000392 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/200...]
        dredmorbius 2y ago
        Thanks!
- lightedman 2y ago
  Absolutely. Anything from landslides to temporary liquefaction of the ground can weaken the caldera or surrounding vents enough to allow the pressure to force magma to the surface or higher.

blackeyeblitzar 2y ago

Can an earthquake trigger a volcano?

jajko 2y ago
Why shouldn't it? I imagine volcanoes as evolving pressure situation slowly tipping towards eruption. Anything that disturbs situation and tips it faster towards eruption, like an earthquake seems as a reasonable assumption. Not that all earthquakes tips it towards it, sometimes maybe it actually relieves the pressure, depends how things move and crack.
dredmorbius 2y ago
It's possible, by several mechanisms. The Mt. Saint Helens eruption was precipitated by a landslide, which reduced pressure over the caldera, leading to a sideways-launched blowout of the volcano itself. That landslide might very well itself have been triggered by an earthquake. Other possible mechanisms would be either the widening of a magma tube or fissure (permitting higher pressures to the surface), or the introduction of water (crustal or near subsurface) to a magma tube, with the ensuing steam explosion precipitating an eruption. The role of water in vulcanism is something I'd not been aware of until relatively recently. The Ring of Fire volcanoes form largely around subduction faults, generally inland of where an oceanic plate subducts beneath a continental plate. The oceanic plate carries with it large volumes of seawater, and as that plate itself intersects with (and is absorbed into) the mantle, that incorporated water flashes to steam. The steam pressure itself then plays a major function in generating pressures and driving magma toward the surface. This is also why volcanic eruptions tend to have so much steam as part of the emergent material, so far as I understand. Another recent eruption in which water (in this case seawater) played a huge role was the 2022 Hunga Tonga–Hunga Haʻapai event, occurring as seawater flooded into a large, shallow caldera, flashing to steam with explosive consequence. Whether or not that event was preciptated by an earthquake again isn't clear, but could be possible. Other mechanisms might have been a cascading failure of the overlying roof of the caldera, with smaller introductions of water expanding access and leading to the catastrophic failure and explosion. There's some scientific research into the question: "A review framework of how earthquakes trigger volcanic eruptions" (2021) <https://www.nature.com/articles/s41467-021-21166-8 https://www.nature.com/articles/s41467-021-21166-8> "Can earthquakes trigger volcano eruptions? Here's the science." (2019) <https://www.nationalgeographic.com/science/article/can-earthquakes-trigger-volcano-eruptions-get-facts-geology https://www.nationalgeographic.com/science/article/can-earth...>
- lazide 2y ago
  Also, “water” (quotes due to the fact it’s hard to actually call it water under these conditions) and sea floor minerals like carbonates change the actual viscosity and chemical composition of the magma in interesting ways that encourage all this too. It’s not just bulk water flashing to steam.
  - dredmorbius 2y ago
    Thanks. I should note that this is all well outside my scope of expertise. Though the raw amounts of water in subducted seafloor are apparently immense. Something which really hadn't occurred to me until recently.
    - lazide 2y ago
      Not widely known I think - here is a neat write up on it [https://repository.geologyscience.ru/bitstream/handle/123456789/37061/Mann_04.pdf?sequence=1 https://repository.geologyscience.ru/bitstream/handle/123456...] And another [https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2002GC000392 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/200...]
      - dredmorbius 2y ago
        Thanks!
lightedman 2y ago
Absolutely. Anything from landslides to temporary liquefaction of the ground can weaken the caldera or surrounding vents enough to allow the pressure to force magma to the surface or higher.