No Errata
Q: How do I resolve the pushes when I play Earthquake?
A: Choose a direction, then push every fighter in that direction simultaneously. Any fighters that cannot be pushed in that direction (because of a blocked hex, another fighter that cannot be pushed, the edge of the battlefield or a rule that prevents them being pushed) are not pushed. As pushing every fighter at once is a little tricky to do with more than a few fighters on the battlefield, it is fine to push the fighters one at a time, so long as you bear in mind that all of the pushes happen simultaneously as far as the game is concerned (so, for example, a reaction to Earthquake – or any push made because of Earthquake – can only be made after all of the pushes from Earthquake have been resolved).