They tend to play a little by their own rules, so without being entirely sure what’s to come next, the USGS are doing the safest thing by letting everyone know magma is on the move and they are observing the shield volcano closely. Remember, when it comes to volcanoes, rule number one (arguably) is that each volcano is idiosyncratic. But the ground deformation is a little like what took place in 2005 and from 2014 to 2018, and no eruption took place after that. Sure, the quakes are comparable to those that preceded a couple of recent eruptions. She added that the HVO cannot yet say how much magma is getting into the shallow cache, but “our geodesists will be working on that.”Ī HVO scientist walks along the Mauna Loa summit path, with Mauna Kea visible in the background. The data simply suggests that “magma is accumulating within the storage complex, straining the overlying rocks, causing earthquakes and inflating enough to push benchmarks on the top of the volcano up and out,” Christina Neal, the scientist-in-charge at the HVO, told me. It just means that there’s some magmatic shenanigans going on down there that’s a little more hyper than it tends to be. No eruption occurred, and that’s what you need to remember: an increase in the alert level doesn’t mean an eruption is ultimately guaranteed. Volcanic regions do this pretty frequently without incident in this case, the deformation is a sign that magma is entering Mauna Loa’s shallow reservoirs.Ĭrucially, Mauna Loa has been at an ADVISORY state before, as recently as the first half of 2018. These are taking place in locations similar to those that took place before two of Mauna Loa’s recent eruptions.Īt the same time, GPS instruments and satellite-based radar has shown that the ground here is deforming. Per the HVO report, this is because seismic stations have recorded roughly 50 shallow, small-magnitude quakes under the volcano’s summit, beneath one of its rift zones (where the ground is gradually being torn apart) and on its upper west flank ever since a sustained quake swarm took place back in October 2018. Right now, Mauna Loa is at YELLOW/ADVISORY, up from NORMAL. YELLOW means there isn’t an ash column present. ORANGE, for example, implies the existence of at most a minor ash plume, whereas RED indicates plenty of ash is getting up into the atmosphere. Although a little similar to the ground-based component, it also attempts to suggest the presence of an ashy plume, the sort that can stall airplane engines. The aviation segment of the alert code – also in all caps for some reason – includes GREEN, YELLOW, ORANGE AND RED. As you can tell, it's not an exact science deciding when to change the alert level for the most part. ADVISORY means that the volcano is showing signs of elevated unrest in some way that’s not qualifiable as background levels WATCH is a stage higher, with the potential for an eruption likely higher (albeit with an uncertain timeframe), and WARNING means that an eruption is about to happen, is happening, or is otherwise very likely to occur.
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