Earthquakes As Existential Risks?

Could an earthquake become an existential or catastrophic risk that puts all of humanity at risk? Seth Baum of the Global Catastrophic Risk Institute and Ariel Conn of the Future of Life Institute consider extreme earthquake scenarios to figure out if such a risk is plausible. Featuring seismologist Martin Chapman of Virginia Tech. (Edit: This was just for fun, in a similar vein to MythBusters. We wanted to see just how far we could go.)