As of April 10th, 2022, there are 51 volcanoes actively erupting on the planet.
One of these erupting volcanoes is the island volcano Karangetang in Indonesia, which is
one of the area's most active volcanoes as it has produced 58 moderately sized explosive
eruptions since 1675.
This figure does not include a number of smaller phreatic eruptions which went unrecorded.
Its latest eruption has been ongoing since November of 2018, which primarily consists
of lava dome growth via viscous lava flows.
These domes occasionally partially collapse, producing pyroclastic flows.
With this being said, here are this week's major volcano related news stories.
In Japan, the Kirishima volcano's alert level was raised from green to yellow due to a swarm
of earthquakes underneath its edifice.
Meanwhile, in Indonesia, there was some confusion regarding one of the planet's most dangerous
volcanoes.
Several widely circulated reports of an eruption were made on April 3rd, yet satellite data
after the fact did not show evidence of an eruption.
And, in Costa Rica, the Poas volcano produced a powerful explosion on April 6th, representing
its first verified eruption since September of 2019.
This new eruption occurred in the very early morning hours of Wednesday, occurring at 2:42
am local time.
Over the course of 3 minutes, a series of pyroclastic flows were generated alongside
a plume of ash which slowly rose to a height of 500 meters or 1,640 feet.
The short eruptive sequence which occurred was a classic example of what is known as
a "phreatic eruption".
While the Poas volcano consists of 4 different small stratovolcanoes, only one vent has produced
eruptions in the last 250 years; Laguna Caliente.
This vent consists of a group of overlapping explosion craters with an acidic crater lake
in its center.
The water has not only pooled in the lake from frequent rainfall, but also because it
represents the height of the underlying water table.
Underneath the water table is a shallow body of magma which consistently heats nearby water.
Over a long enough period of time, or if the magma intrudes further into the magma conduit
than is typical, the adjacent groundwater will flash to steam.
Since steam takes up more volume than the same mass of liquid water, it causes an immense
amount of pressure to build.
This pressure is eventually released in a phreatic eruption which does not eject any
lava.
Because of this latest eruption at Poas, it means that more such phreatic eruptions can
be expected in the near future over the next several weeks.
In Indonesia, the dangerous volcano known as Mount Agung was reported by several outlets
to have produced an eruption on April 3rd.
This apparent eruption triggered a volcanic ash advisory, as satellite data showed a plume
expand to a height of 3,700 meters or 12,000 feet.
However, there was a major problem with these reports.
According to those who lived adjacent to the volcano and the local volcanological institutes
within Indonesia, no eruption ever occurred.
Earthquake activity at Agung was also quite average, with no notable changes suggesting
an imminent eruption.
Thus, this incorrect report has two possible origins as an eruption truly did not occur.
Possibility 1 is that a nearby forest fire which was photographed from satellite triggered
the ash advisory, and Agung was incorrectly attributed as its source.
Possibility 2 is that the satellite was processing an unusually noisy dataset, leading to its
data attributing a false positive.
If you are worried about Agung erupting anytime soon, there is no need to worry, at least
for now.
This volcano which I ranked in a previous video as the 13th most dangerous volcano on
the planet is still producing only a normal non eruptive level of earthquakes.
In Japan, the Kirishima volcano has been showing signs of unrest since March 1st, when a swarm
of earthquakes began underneath the Shinmoedake vent.
These earthquakes were eventually attributed to the movement of magma at depth, as they
occurred alongside a small amount of uplift on its summit.
This caused Kirishima's alert level to be raised from green to yellow, which triggered
a 2 kilometer exclusion zone around the vent.
A further development occurred on March 31st, when a second series of quakes struck underneath
an additional vent to the northwest which has also been the site of recent eruptions.
While an eruption is still uncertain, there is definitely an increased likelihood of one
occurring anywhere in a line between these two vents.
As a result, the prior exclusion zone was further expanded.
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.
Thanks for watching.
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