This part of Indiana I live in is pretty flat. Dull, right? So I figure, why not have a volcano? Now... I get my magic drill machine that can drill as deep as I want it to drill.
If I drill a deep enough hole, say through the crust of the Earth, will it turn into a volcano?
That could actually work, since the hot material has a lower density and will thus be pushed out.
But the hole needs to be somewhat big, since it will just solidify on the way up otherwise. So maybe 100 meter diameter?
Probably still won't work unless there is serious overpressure in the area from some dynamic loading in the mantle. First off, no part of the mantle is naturally fluid at depth. The closest is the asthenosphere, at around 200 to 400 kn depth. This is still solid, but more like a soft wax. That too, the material is made of peroxides and has a density of between 5 to 15 percent higher than the granitic crust at depth and limestone that makes up the shallower crust of Indiana. Thus, it would be analogous to a whole in a wooden plank floating on a sea of dense soft wax...the wax won't likely push through.
However, if you add water to the system while maintaining the heat, you can start to fluidize the gooey rock, and eventually it will reduce density enough to start creeping upwards. If you mix it deep enough and we'll enough, you can start creating small steam bubbles within that will continue to grow as the rock ascends, further increasing the pressure (like a bubbly bottle of champagne). This will drive further upward pressures allowing for a surface eruption and formation of a volcano.
Source: am geophysicist and play(work) on volcanoes...just not in Indiana
If the lower layers are denser despite their much higher temperature and also super viscous, how can volcanos ever form?
What if we drill right through this area with an even later size hole?
In this caw tho, note that all of the back-pressure is missing at the hole, so gases would violently went to escape (10'000s of bar vs. 1 bar), which should be plenty of driving force to get stuff above the ground. Due to the outgassing the density should also massively decrease. Kind of like lowering a pipe into a volcanic lake that has CO2 dissolved in the deeper layers and letting that vent in a fountain.
you can start creating small steam bubbles within that will continue to grow as the rock ascends, further increasing the pressure (like a bubbly bottle of champagne).
Note that the pressure would go down, not up, as it ascends. But the volume would go up because of the lower pressure.
It'll get more complex than that. I'm no expert, but I'm guessing you have to consider the depth of the crust at your location, type of soil and the distance from (and time since) the last closest volcanic eruption, possibly distance from the nearest tectonic boundary, maybe even tidal forces (assuming they have a considerable impact on magma being pushed out, but this may be a bit too far)
The closest eruption was the snag point I was thinking. We're relatively near a fault line, but I don't know of any volcanoes for a very, very long distance.
This region is thought to have been the site of extremely powerful volcanic activity in the past, so powerful that it caused mile-deep lava over an area as large as the state of California.
By Richards’ estimate, the asteroid impact must have generated the equivalent of a magnitude 9 or larger earthquake everywhere on Earth
Besides the earthquake, there was also a literal rain of fire across the planet, like a blast furnace, that likely killed everything that wasn't underground or underwater.
Is What If? still running? Last time I tried looking, it wasn't. Someone on the forum said that he was working for a newspaper or magazine, and the images were being published there. Typically, it was not available outside the US.
The Red Mars series of books by Kim Stanley Robinson includes a range of measures that humans take to terraform the red planet, one of which is building robots to drill "moholes," or holes that reach the Mohorovicic discontinuity between crust and mantle layers. Yes, they are giant volcanoes, and in the books the outgassing from these volcanoes is a strategy to increase the density and particularly the infrared absorption of the Martian atmosphere.