As recently as February 2016 an article in a prestigious
science journal (Nature) raises the question if a nuclear blast will have an effect
on a volcanic eruption? I’m continually amazed at the fixation people have with
nuclear devices; this “nuclear question” arose during the 2004 Mount St Helens
eruption and again during the 2010 Deepwater Horizon seafloor oil blowout. This is a variant
on the same theme, but at least doesn’t suggest some fallout-creating
experiment. People who think a nuclear device is comparable to the energy released by a volcano just haven't seen a restless volcano up close. They are a whole lot bigger than they seem to be in the films. Mount St Helens is a relatively small volcano, yet it still took me nearly 6 hours to walk out of the center crater.
Q: So I am watching this tv show (What on Earth) that NASA
scientists have found a super volcano that has a potential to explode in a
relatively near future in Italy. I'm super curious about a lot of things, but I
won't waste your time. Whether if it's true or not, my question(s) is(are): Would
it be possible to hypothetically drill into a deep caldera to release pressure
on a magma chamber? I get that the chamber is quite a ways down and it would
cost a FORTUNE, but if a drill was created to do so, would it work? And (if so)
would it be a plausible reason for the world to come together to survive? Thanks
for your time, I know you guys are busy.
- Jon T
A: A thoughtful question. You are probably referring to
Campo Flegri, a 13-km diameter nested caldera in western Italy. However, there are
quite a number of much bigger supervolcanoes around the earth, including at
least three "owned" by the United States: Yellowstone (mainly in Wyoming),
Long Valley (California), and Veniaminof (Aleutians).
Unless you spent time on a drill-rig, you would probably not
realize that even very large ones used for hunting deep hydrocarbons (like the
Deepwater Horizon rig) have limited borehole sizes, particularly at depth,
where they reach a human body diameter or less. The active magma chamber at
Yellowstone is at least 45 miles (70 km) across northeast-southwest (wider at
depth), and lies as shallow as 4 miles (6 km). There is a reason for all the
geysers and Morning Glory pools: rain and snow-fall seep downward until they
reach an upper magma chamber that is estimated to contain perhaps 48,000 cubic
kilometers (11,000+ cubic miles) of molten magma. *
Perhaps you can see where this is leading. A single
drill-rig would not even be seen in an image that encompassed the entire
caldera. Not even all the drill-rigs on earth (if they could even successfully
drill down that deep) would have any noticeable effect. The scales are just so
many orders of magnitude greater. Think of a fly doing push-ups on the roof of
your house. You get the idea.
There was an experiment years ago to drill through a recent,
100+ meter-thick recent crust in Kilauea Iki crater on the Big Island of
Hawai'i. The drill crew kept losing drill bits to the heat, but eventually they
got a hole far enough down that a camera above it would catch a red glow from
incandescence at some depth below the top of that lava crust. I don’t think
they penetrated into the lava. Even if we had giant drills and lots of them,
getting a drill bit to a magma chamber is not really possible. And it takes a
LONG time to drill even a small hole in cold rock to those shallowest depths.
* Incidentally, the reason volcanologists are not
particularly worried about Yellowstone right now is that estimates of crystal
content in the magma mush (from seismic data) range upwards of 95%. That means
it's very hot, but verging on solid. We don’t rest on this knowledge however. Geologic
history tells us that a shot of deeper mantle basalt into the base of that
crystal mush can quickly remobilize and prime the whole system for another vast
eruption. The last supervolcano-scale eruption was 640,000 years ago, and
before that another at about 1.2 million years ago. From our experience, we
would first certainly see a ramping-up series of warning signs, including
inflation leading to regional ground-tilt, rock-breaking manifested in a
seismic swarm with a pattern to it, and the release of unusually large amounts
of volcanogenic gases such as H2S and CO2.
Q: Thank you so much for the information! I was extremely
excited to see someone replied. I guess I didn't realize our drill rigs were so
small -- and the volcanoes so freakin' huge! That's absolutely mind-blowing. I
love learning these new things about geology, the planet, space, etc. Science
just fascinates me. Thank you for your time!
- Jon
