Another point is that every stress point on the Earth's surface will let loose as tectonic plates adjust to the sudden strain put on their already stressed faults. And while dead volcanoes will remain mountains, everything else will suddenly find itself under a tremendous urge to erupt. Including those volcanoes that produce sheets of lava that spring upwards from under fragile cracks along thinner portions of the Earth's surface.
Consider this: If you lived in Denver and tonight there was a relatively minor 3 degree crustal shift, you would wake up at the same latitude as Casper, Wyoming, or Albuquerque, New Mexico. If there was a 15 degree displacement during the night, you would wake up about where the bottom of the Hudson Bay is today, or perhaps as far south as Mazatlan. In addition to the stress such a move would put on the mountains, volcanos, and tectonic fault zones, either every water source would freeze overnight from moving into the colder latitudes, or all the mountain snow and ice would melt as you woke up in the middle of Mexico.
As you ponder this, I'll be working up another post to talk about some of the other issues sure to arise from the upcoming catastrophe.