As of July 3rd, 2022, there are 48 volcanoes actively erupting on the planet.
One of these erupting volcanoes is Masaya in the nation of Nicaragua, which has been
intermittently erupting with a small lava lake since October 3rd of 2015.
This lava lake has long drawn in visitors, including a group of miners during the era
of Spanish Conquistadors who tried to extract buckets of this molten material, incorrectly
thinking that it contained large quantities of gold.
With this being said, here are this week's major volcano related news stories.
In New Zealand, Mount Ruapehu is beginning another warming cycle, meaning that the odds
of a volcanic eruption in the short term have once again increased.
Meanwhile, in Nicaragua, the San Cristobal produced a sudden vulcanian explosion, sending
a plume of ash more than 1,000 meters into the sky.
And, in Alaska, 3 volcanoes are erupting but what is more interesting is that several more
which are not erupting are showing signs of unrest through magmatic uplift.
At an active volcano, ground uplift is one of the most important features to keep track
of, as whenever it is detected it almost always indicates that magma is moving at depth.
As magma rises to the surface, it pushes overlying rock upwards, causing a bulge which is detectable
from satellite.
For example, the Mount Edgecumbe volcano near the town of Sitka has been producing magmatic
uplift since mid 2018.
Since then, the ground has been uplifted by about 12 inches, owing to a fresh intrusion
of magma at 3.1 miles or 5 kilometers in depth.
Although the frequency of magmatic uplift events at volcanoes vary, two crucial factors
are the rate of eruptions a volcano has and the size of its largest eruption.
Volcanoes which have produced large eruptions on the order of more than 10 cubic kilometers
of material ejected in a single event must have magma chambers which at a very minimum
hold that volume of molten rock.
Thus, magmatic uplift is most frequently detected at volcanoes with large calderas, and this
report on Alaskan volcanoes is no exception as each of the 4 volcanoes being uplifted
contain large calderas.
In addition to Mount Edgecumbe, the following volcanoes are slowly being uplifted by magma;
Westdahl on Unimak island, Okmok on the Aleutian peninsula, and Akutan adjacent to the city
of Akutan.
This information was retrieved by satellite data, scientific papers, and asking the Alaskan
Volcano Observatory.
However, the Alaskan Volcano Observatory noted that uplift at Akutan had temporarily paused.
Statistically speaking, it is unlikely that any single one of these intrusions will produce
a new eruption this year, as 9 times out of 10 a magmatic intrusion does not result in
an eruption.
However, a close eye will continue to be kept on these volcanoes just in case signals suddenly
do trend towards an eruption.
In New Zealand, the Ruapehu volcano is once again displaying an uptick in overall activity
owing in part to an increase in temperature at its crater lake.
The temperature of this lake has recently varied anywhere from 20 to 51.4 degrees Celsius,
with the high point on this scale occurring right before Ruapehu produced a major explosive
eruption sequence in 1995 to 1996.
Although Ruapehu has frequent several week to month long crater heating and cooling cycles,
this current cycle has been ongoing for the longest period in more than 2 decades.
A temperature of 28 Celsius on March 13th became a peak of 41 degrees Celsius on May
8th, during which intermittent steam plumes became visible on Ruapehu's summit.
Afterwards, the lake temperature slowly decreased to 22 Celsius by June 20th.
Since then, however, a new heating cycle has once again began as the crater lake has increased
to 25 degrees Celsius.
Thus, although a phreatic volcanic eruption could technically occur at Ruapehu's summit
with little or no warning, the current odds are rather low and one is less likely to occur
than it was on May 8th.
In Nicaragua, the San Cristobal volcano has been intermittently erupting since December
27th of 2020.
Its eruptive activity has largely consisted of intermittent vent clearing vulcanian explosions,
which have generally sent ash to a height of between 400 and 2,000 meters above it.
One such explosion occurred at 7:51 am local time on June 26th, sending a moderate sized
eruption plume to 1500 meters above the crater rim.
Ash from this eruption later drifted to the southwest, causing a dusting of material to
fall on several towns up to 18 kilometers distant.
Here is a quick list of every volcano which is currently erupting.
Also, here are some volcanoes showing signs of unrest which are not erupting but could
erupt in the near future.
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at the Utah Military Academy.