It seems like a lot of big aftershocks for a 5.4-quite a handful over M4 if the USGS page is correct. Is this normal, or is this a cross between aftershocks and a swarm?....we'll see if this dies out at the usual rate (whatever that is) or if there is a sequence (maybe with some located at distance, as was the case in 1992, although for much larger quakes...). Chris