As of January 30th, 2022, there are 50 volcanoes which are actively erupting.
This figure is within the typical range of activity as at any moment there are generally
between 40 and 50 volcanic eruptions ongoing.
The list of erupting volcanoes includes Nevados de Chillán in Chile, which has been erupting
intermittently since 2016.
Although its ongoing eruption is rather small, the volcano on several occasions more than
ten thousand years ago produced pyroclastic flows which traveled more than 100 kilometers
or 62 miles from its summit.
With this being said, here are a few of this week's major volcano related news stories.
In Alaska, the alert level was once again raised at the Davidof volcano as it was hit
by a swarm of shallow earthquakes.
This volcano is often colloquially called "the Alaskan Krakatoa".
Meanwhile, in Vanuatu, two new volcanic eruptions began while an additional two other volcanoes
could erupt at any moment.
And, in the nation of Tonga, the Hunga Tonga Hunga Ha'apai volcano was hit with a swarm
of several major earthquakes.
On January 14th and January 15th, the Hunga Tonga volcano produced a series of powerful
eruptions which obliterated more than 95% of its land above sea level.
Although this eruption officially ended on January 15th, numerous earthquakes with a
possible magmatic signature to them have since hit near the island.
For example, within a 50 kilometer radius of the now destroyed edifice, 42 earthquakes
of magnitude 4 or higher have occurred since the eruption.
All 42 of these quakes occurred at shallow depth and can be interpreted as occurring
due to the movement of magma.
However, there is another possible explanation.
These earthquakes could simply be caused by the crust releasing stress after a large mass
of rock overlying the area was removed in an explosive eruption, much like removing
a weight from a spring.
Additionally, we aren't yet sure if a caldera collapse occurred, but if one did, then some
of these earthquakes would definitely have a magmatic signature.
I personally think the cause behind these earthquakes is a mixture of all three explanations.
As a whole, this earthquake sequence seems ridiculously similar to those witnessed after
a caldera collapse during the 2018 submarine eruption of the Mayotte volcano.
Thus, while these quakes continue, the chance of Hunga Tonga Hunga Ha'apai erupting again
continues to increase.
In the remote part of the far western Aleutian Island chain, the alert level at a volcano
which has not erupted in more than 10,000 years was once again raised from white indicating
not monitored to yellow.
This change was made on January 26th, and was done in response to a swarm of earthquakes
underneath its edifice which had a possible magmatic signature to them.
While I was unable to see uplift signatures suggesting an intrusion of magma, this could
simply be due to the available data only going up to January 25th.
Regardless, I am of the opinion that a dike intrusion of magma is ongoing underneath the
volcano, as many of the earthquakes are seemingly trending in a north-northeast orientation.
This hypothetical intrusion is likely occurring at around 4 kilometers in depth and involves
a small volume of magma, possibly around 50 million cubic meters of rock.
In the low chance this intrusion of magma was to reach the surface, it would cause a
small explosive eruption which might disrupt regional air traffic.
Although there is a lot of interpretation going on in my analysis, I do not think another
caldera forming eruption will occur.
The creation of Davidof's 2.5 kilometer or 1.6 mile wide caldera which defines this volcano
involved a far larger volume of magma.
In Vanuatu, the country has always had at least one of its volcanoes be actively erupting
for the last 700 years as that is how long the Yasur volcano has been continuously erupting.
However, in recent weeks, four other volcanoes were placed on a raised alert status.
Two of these subsequently produced new eruptions, Ambrym on the 25th and Aoba on the 26th.
These eruptions have so far been explosive but relatively small, and are confined to
the large summit calderas these volcanoes have.
Luckily, there is nothing to suggest that a larger explosive eruption is imminent.
Here is a quick list of every volcano which is currently erupting.
Also, here are some volcanoes showing signs of unrest which could erupt in the near future.
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