Within the last two weeks, a relatively unknown volcano has come onto the radar due to an
apparent and sudden eruption in the Solomon Islands.
The volcano I am referring to is called Savo Island, whose name was used to a describe
a major world war 2 naval battle.
Although there are many false rumors claiming that the island exploded, this is not the
case.
However, there were definitely at least three volcanic explosions on July 28th, 2021 which
originated on the eastern side of the volcano's main crater.
Since then, earthquake activity has decreased, suggesting that the eruption may truly be
over.
However, if we look back in the history of this small volcano, we can see that it has
produced far deadlier eruptions that required the complete evacuation of the entire island.
This video will discuss this volcano, describe what might happen next, and mention what its
future hazards are.
The Savo Island volcano can be found 1390 kilometers east of Port Moresby.
The entire island is volcanic in origin.
Before I go into detail about this volcano, let me describe exactly what happened.
Although technically unconfirmed, the explosions heard by thousands in the afternoon of July
28th were likely small phreatic eruptions.
Phreatic eruptions are a variably sized type of volcanic eruption caused by the interaction
of rising magma with groundwater, which does NOT erupt any lava.
The rising magma heats surrounding rock, causing at depth temperatures to increase.
If these temperatures reach a certain threshold, they can cause any groundwater in the vicinity
to flash to steam.
Since steam takes up far more space than liquid water, it strains the enclosed space it is
in, causing pressure to build.
Eventually, this triggers an explosion, causing an eruption on the surface.
Another recent example of a phreatic eruption occurred during the 2021 eruption of Taal
in the Philippines.
What might happen next could widely vary.
Sometimes, phreatic eruptions occur on their own as isolated events, such as the phreatic
eruption of Morne Watt in 1997 on the island of Dominica.
Other times, they represent the beginning stages of a much larger eruption.
Given the very limited monitoring equipment placed on this island, I cannot truly say
which of those possibilities will come true.
I would stay wary, and be prepared to evacuate off the island with only a few minutes notice.
During previous large explosive eruptions, the Savo Island volcano has destroyed all
life on the island, meaning that no part of the island is truly safe during an eruption.
With this being said, a series of hills on the southwestern section of the island offer
a minimum level of protection from pyroclastic flows.
Luckily, large explosive eruptions on Savo Island seem to almost always be preceded by
the growth of a lava dome.
Thus, if a lava dome begins to form, the entire island should be evacuated.
Although we aren't truly sure how old the Savo Island volcano is, it likely is only
40,000 years old.
The island represents the emergent summit of a 9 kilometer wide submarine volcano which
began at a depth of 950 meters.
After a period of many thousands of year, the island likely first broke the ocean's
surface 16,000 years ago.
The main volcanic cone which continued to climb above the ocean was marked by repeated
lava dome forming eruptions out of a black lava known as basaltic andesite.
Initially, these eruptions were centered in what is now the southwest of Savo Island.
However, over the many thousands of years since, the type of lava changed from basaltic
andesite to andesite, and then to dacite.
This change in lava has marked a pattern of increasingly explosive eruptions.
Almost all of these eruptions originated in the 1250 meter crater at the volcano's summit.
The small lava dome in the northeast of this crater formed in 1568, as the conclusion of
the island's largest recorded eruption.
This vulcanian style eruption created large flows of material called lahars which greatly
expanded the island's shoreline via debris fans.
Two other smaller eruptions occurred in 1650 and then again in 1835.
The 12 year long eruption which began in 1835 once again expanded the island, but this time
to the east and south.
As for today, we need more information to see what will happen next at this active volcano.
I hope that you enjoyed this video!
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