Question: How do earthquakes start

Tim Craig answered on 11 Jun 2018:

This is an excellent question – and one to which we currently don’t have a good answer. How earthquakes start, or, in technical terms, “nucleate”, is a very active topic of research at present. Hopefully , if you ask this again in a few years, we’ll have a real answer – or maybe, one day, you can help work this out!

One of the most important aspects of this, which we really want to understand, is whether an earthquake ‘knows’ at the point when it starts exactly how big it will be – if that turns out to be the case, then it opens up options for rapid “earthquake early warning”, which is starting to be developed in places like California, Japan, Mexico, etc.