Beginning on March 24th of 2023, a rapid increase in the number of daily seismic events occurred
at the towering and glacier covered volcano known as Nevado del Ruiz, which happens to
be one of the planet's most historically deadly volcanoes.
By March 28th, the number of daily seismic events had increased to 6,500, marking the
most Nevado del Ruiz had produced in a day since 2010.
The following day this figure jumped to 11,000 seismic events, marking the most ever recorded
from this volcano since it was first properly monitored, even being more than recorded on
the days on and surrounding its devastating November 13th 1985 eruption which caused approximately
25,000 fatalities, most of whom lived in the town of Amero 47 kilometers away from its
summit.
While that 1985 eruption was only medium sized in terms of volcanic eruptions around the
world, it was large in the context of the last 400 years at Nevado del Ruiz.
The reason that eruption was so deadly yet only barely registered in as a 3 on the 0
to 9 volcanic explosivity index relates to the abundant and thick glaciers at the summit
of Nevado del Ruiz.
When an unusually powerful eruption occurred on November 13 1985, the eruption released
several hundred degrees Celsius pyroclastic flows, and this heat rapidly melted approximately
14% of the entire glacial ice present on the volcano, causing a torrent of mud, superheated
ash, water, and debris to race downslope at a speed of 50 kilometers per hour or 31 miles
per hour via what is known as a lahar.
This lahar created a wall of material up to 40 meters or 131 feet high which bulldozed
all structures it encountered.
Reaching the town of Amero a little less than 2.5 hours later, the lahar quickly wiped out
the town and lead to 20,000 fatalities.
Similar lahars from that eruption occurred in other drainages of Nevado del Ruiz on that
terrible day, including to the west-northwest where it also caused a large loss of life
in the town of Chinchina.
Back to the current situation in April of 2023, I want to remind my viewers that Nevado
del Ruiz has been erupting intermittently for much of the last decade and is technically
erupting at a low intensity right now.
The dramatic spike in earthquakes which occurred was believed to be caused by a new intrusion
of magma moving from southwest to northeast at a depth of approximately 2 to 4 kilometers
underneath the top of Nevado del Ruiz.
Although not proven, in my opinion this new intrusion is likely volatile rich and has
a high silica content, hence the number of earthquakes it is producing.
As a result, the alert level was raised at this volcano from yellow to orange, with orange
meaning that a larger than typical volcanic eruption is possible in the next several days
to weeks.
Such an eruption could in a worst case scenario generate long reaching and destructive lahars
due to melting of the glacial ice on Nevado del Ruiz, possibly reaching areas as far away
as 75 kilometers distant from its summit.
However local authorities will only order an evacuation if the situation continues to
progress and a large eruption does become all the more likely.
Thus, I ask everyone who lives within 75 kilometers of this volcano to pause the video and click
on the link in the video description, as it will bring you to a hazard map that shows
if you live in an area which could be effected by pyroclastic flows and/or lahars.
With all of this being said, a large volcanic eruption is far from a certainty.
In fact, the current situation marks the 6th time since 1987 that Nevado del Ruiz has been
at an orange alert level, with the other 5 prior occasions being shown for comparison.
None of these 5 instances produced a similar sized or larger eruption than what Nevado
del Ruiz produced on November 13th of 1985.
Thus, while a medium or even large sized eruption is theoretically possible, past statistics
suggest that one will probably not occur, with even a medium sized eruption not being
a certainty.
Thus here are a series of outcomes which might occur which are completely based on my opinion
and are ranked from most likely to least likely.
In other words, in my opinion a large eruption which may or may not generate a destructive
lahar is theoretically possible but overall unlikely.
There is NOT currently a reason to panic right now in my opinion, but because there is a
very small possibility that something destructive could occur even if it is unlikely, keep your
eyes and ears peeled for further developments.
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