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
I know I'll regret asking this, but what if in a sufficiently deeop hole where the rocks are hot enough to glow red we used explosives to fragment the rocks around the end of the hole? Could be conventional (insane) or nuclear (supervillain-level). Would that be enough to make a hot magma column reach the surface and make a "magma geuser"? Would the pressure be enough to keep the magma flowing through the hole?
ReplyDeleteBTW, what kind of cooling is used on the drill bits to prevent them from overheating (in cases you are not trying to pop a geological scale pimple)?
@Ricardo Bánffy: Unlikely to do much beyond making the eventual eruption even more deadly 😅 However, if one could divert a huge asteroid from outer space fast enough to hit it, things might get interesting.
ReplyDeleteLOL. Both scenarios are fun but vanishingly improbable.
ReplyDelete1. Asteroids near the Earth are NOT that near the Earth. Changing their momentum would be minuscule even with a powerful rocket and/or explosives. There is an experiment underway right now to measure how many CENTIMETERS a small asteroid can be moved by the NASA DART spacecraft.
2. Any drillbit must be cooled by recirculation fluids, which are mostly water. If the magma has a temperature of (typically) 1300 C, the circulation fluids will be vaporized hundreds of meters before the drill can make initial contact with magma. It would become incredibly dangerous for the drillers, for starts. Moreover, a drillbit will not be hard enough to grind through rock if it partially melts.
- But keep on thinking about this problem. That's the only way a solution will eventually be found.
To prevent the coolant from evaporating too far from the drill bit, we can inject it supercooled. If the drill is deep enough, the pressure of the water column will also increase its boiling temperature and we can pressurize it at the surface even more, just to keep the drill bit from getting too hot. We could also drill secondary holes that encounter the main one so we could inject more coolant.
DeleteOf course, it'd be extremely dangerous for the surface crew, but these brave pioneers should expect that while working on a project to drill directly into a supervolcano with the expectation of making a lava geyser.
As for the asteroid, one issue could be that, by the time we manage to nudge it enough to hit the supervolcano, it may have moved in the intervening millions of years.
Two questions:
ReplyDelete1. Given what you described with the recirculation of fluids and the steam generated in such a scenario, could you use this to make a geothermal power plant? (I'm assuming we don't need to get down quite that far for this purpose) Would something like that be economically feasible as a power generation methodology or would the seismic activity be to problematic? (Nice renewable energy source for those in the area?)
2. I hope you enjoy math for this next question. Given the above scenario was feasible. Let's use Campo Flegri, for this example, which you indicated had a 13-km diameter. If you had 3-meter wide pipes, hundred meter long across, every hundred meters or so, circulating water into an above ground power station, would it be enough to bleed ANY energy off the magma chamber? If not, how close would the pipes have to be to cause any kind of cooling effect on the chamber? I saw this concept originally on a PBS Nova episode I believe, and just wondered if it was mathematically feasible.
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