When volcanoes erupt in movies they do so unexpectedly, and the eruption lasts as long
as the story needs it to last, but c'mon science, what's it REALLY like?
I think my producer, Pam, had it right when she said, "Volcanoes and dinosaurs are some
of the first things that get people excited about science."
Volcanoes are incredible to witness, unless you live in the path of one.
They can be destructive, dangerous, and deadly, but they're a glimpse into the awesome power
of the planet beneath all our feet.
This week, unexpectedly, after 42 years of silence, Calbuco volcano erupted in southern
Chile.
Residents had 15 minutes of warning, and 4000 people had to be evacuated as the volcano
spewed ash into the sky.
No doubt, residents are asking how long can this be expected to continue?!
According to research from Smithsonian Institution's Global Volcanism Project, the median length
of a volcanic eruption is seven weeks, but the length of volcanic eruptions throughout
scientific history is SUPER varied.
For example, the crater at the top of mount Nyiragongo in the Democratic Republic of Congo
held a lava lake from to 1894 to 1977, but when it "erupted" the lake drained in less
than an hour.
Conversely, the eruption of Stromboli volcano off the coast of southern Italy has had low
level activity and occasional lava flows and explosions since 450 BCE!!
Stromboli's been erupting for almost 2500 years -- most recently, with fairly large
explosions in August 2014.
The length and behavior of these long-term volcanic eruptions can teach volcanologists
and geologists a TON about the ground beneath our feet.
Mountains are created when tectonic plates jam together, forcing rock upward, or when
magma from underneath the Earth's crust rises through a weak spot, creating a volcano.
Magma is like a bubble in water, it's lighter than the rock around it, and slowly rises
until it hits the surface.
As magma gets closer to the surface, gases appear inside the magma -- like nitrogen bubbles
in a diver's blood.
When the magma and gas reach the surface, they EXPLODE into the comparatively thin atmosphere
above the crust -- when that happens, it's just like a soda that's been shook up.
Bubbles and explosions galore.
In 1983, magma under mount Kilauea in Hawaii forced open a rift 6.4 kilometers (4 miles)
long!
When Kilauea cracked, lava fountains shot 1,500 feet (460m) into the air, with activity
continuing for 3 years before more cracks spread the pressure under the volcano around
-- causing a low-level continuous eruption which is still ongoing today, 32 years later!
Now, the eruption is used to learn more about how lava behaves, and how magma flows beneath
the crust.
Scientists studying the Kilauea eruption -- and the nearby new Pu'u 'O'o (pooh-OO-oh-oh) volcano
that formed over the crack -- have learned more about the tectonic plates our planet's
continents ride on, how earthquakes happen, and more about the toxic gases that escape
during volcanic activity.
They can also track the slight swelling of the rock at the volcanoes surface to find
the magma pipes which feed the eruption -- sort of like the volcanoes blood vessels.
Luckily, Chile's Calbuco isn't near any major population centers, but when it erupted in
1895 it threw 30-cm bombs (1 foot) 8 km (5 miles) from the eruption site.
So, this isn't the big one for ol' Cal.
Chile has many hundreds of volcanoes, and according to Penn State, this eruption will
continue until the magma melt beneath the volcano has stabilized, and the pressurized
gas which has built up is released; but, honestly, no one can tell exactly how long that will
be.
Volcanoes are so cool.
Seriously, who doesn't love watching these things?
From a safe distance
of course.