Submitted by lostinthought1997 t3_z6bbrn in askscience
If a sufficiently large asteroid were to strike the earth, could the impact cause internal stresses that would cause volcanic eruptions on the other side of the planet? Why or why not? Edit: it says I have 6 answers, but I can only see one. Why?
Nepene t1_iy31itl wrote
Earthquakes don't reliably cause volcanoes. We saw this with 16 April 2016 Kumamoto earthquake and the nearby volcano Mount Aso 30km away, which didn't erupt. This is because most volcanoes aren't waiting to erupt. They have a magma chamber several kilometers below the earth and the supply of magma to that chamber is the main cause of whether they erupt or not. Luck might cause an eruption, but it's hardly reliable.
Volcanoes aren't like ticking time bombs waiting for a minor trigger to go off. They depend on having enough magma to be set off.
Of course, a large enough one might start moving substantial amounts of the mantle, or causing enough stress to get magma to forcibly erupt from the ground. It would have to be very big to do that.