A bit about the 10/14/2022 (yesterday) eqs under the southern flank of Mauna Loa..
These two events, happening a few seconds apart, created a remarkable long undulating eq, and were interesting in a few other ways worth mentioning.
To begin with, their location is in the Pahala area. This site is the location of an ongoing, and active since eqs have been recorded (over 100 years), seismic swarm, that is interpreted as the location of the deepest (approx 20 km) measurable source of magma rising into the active volcanoes that make up the island. How magma migrates, ascends, from this location into one or the other volcanoes involved is less understood. An interesting thing to note is that after the 2018 voluminous eruption, and subsidence of the summit of Kilauea, this swarm markedly increased. And to this day is a wonder.
Another thing to note that there are large, sometimes lasting tens of minutes up to an hour at a time, tremor bursts recorded in this location. These are believes to be the upwelling of magma through the earth’s crust in the same area. This is as close to the magma’s source that seismicity gets. Below that the Earth is assumed to be too plastic to generate recordable vibrations. And, there has been no sign of a tremor event associated with yesterday's eqs.
So, absent any other factors yesterday’s events would be simply assumed to be a part of the general noise that the mountains make in that area. But there are other factors that may be involved, and when all is said and done these events may be interpreted as a part of the ongoing unrest at Mauna Loa.
As I posted a few days ago at..
http://earthboppin.net/talkshop/geology/messages/96132.html
The volcano is in a seriously heightened state and an eruption is considered possible within hours from the first signs we might see of a final push of magma to the surface. And this, based on the mountain’s history, has the volcano community concerned. Though an interesting policy of the USGS is not to predict as much as state clearly historic precedent (nor do they flood social media with silly run for your life youtube vids), and as such allow other’s, local governmental bodies, to assume responsibility for public safety and all that. We could argue around this issue until we’re all blue in the face. After all the federal government's history of a hands off approach to eq predictiveness is the root of the entire EB community and our origin in JOB’s willingness to speak out on that matter. As it is, as California does, the Hawaii county and state governments do not have their own geologic advisers and as such they defer to the USGS, who has a strong presence here, and as such we lack an official Chicken Little to herald in events.
The thing about the historic events of Mauna Loa is that in most scenarios, and if the volcano follows it’s own precedence, there is every reason to worry we have a major crisis developing because of the county and state's attitude towards volcanic preparedness (it’s almost nonexistent), and their willingness to not consider natural dangers in their land use policies, and as such the amount of development that is now in the volcano’s path.
To understand what this could mean keep in mind that a Mauna Loa eruption usually starts at its summit and if it is going to migrate from there it will in short order move to the west or the east, and within a a few hours to a few days settle on vents that it will erupt from for it’s duration. If the eruption goes west, then there is no way to imagine it does not have serious, potentially life threatening, impacts within hours on the West Kau and South Kona populations. Another thing to understand is at its onset the volcano puts out a massive amount of lava..
To graphically appreciate this watch this old, NPS, video of the last eruption on that side of the volcano..
https://www.youtube.com/watch?v=-l__Aj3XyGo
And read the HVO article about the same..
https://www.usgs.gov/news/volcano-watch-1950-eruption-mauna-loa-nightmare-could-reoccur
Alternatively, if the eruption, as it did the last time it erupted in 1984, goes east it is probable that it would settle in the Red Hill area, at the 9,000 foot elevation. And, as it has done for several historical eruption in that area, it is possible the lava flows would go northeast towards Hilo. If it does it will take a long time before it would be a concern, or develop into a crisis, if it does at all. But, there is an obscure paper by Jack Lockwood (who is a retired volcanologist from HVO) that should be noted, and can be read here..
https://pubs.geoscienceworld.org/gsa/geology/article-abstract/18/7/611/198850/Implications-of-historical-eruptive-vent-migration
And although that is a paywalled site the Abstract and Introduction that are freely available are enough to understand the implications, and potential threat, to the Puna district that to this day has thought itself outside of the volcano’s path..
Both these areas on the island have had phenomenal growth since they were last under the threat of inundation. Both these areas have poor access and egress, and the local government has no way to facilitate a large scale evacuation in anywhere near the amount of time there would be a warning of impending activity. As such there is every possibility that an eruption, when it happens, could be a real human tragedy.
Ok, enough said. I am sure I’ll have more if/when this all unfolds..
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