Saturday, March 29, 2014
Los Angeles M5.1 - A Fine Foreshock to a Northbridge
Yeah, I can be totally irresponsible here because nobody reads me, and I have established my reputation as a nut. So liberating!
Very weird that an M5.1 has a 10 km long aftershock zone. This makes it a potential M6.5. And it is thrust, probably along one of those deep blind thrusts that nobody has mapped. California puts all its trust on mapped surface faults - Big Ha Ha! There is never going to be another earthquake along one of those.
Having said all this, the recent Greek earthquakes did exactly the same thing and nothing happened. It's a wonderful consequence of an uncertainty fuzz that exceeds all trends, much like global warming. The M5.1 has a thrust component which makes it even more suspicious.
But, getting down to brass tacks, the odds of this going runaway are the same as the average odds, which is something like 1-10% chance of an M6.5 in the next 48 hours. This is slightly above the standard odds of this happening without any foreshocks. Residents should be prepared as they always are and don't do anything stupid.
Update: It seems to have a very high PGV in the hammer zone (for a 5.1). I hope they get some strong ground motion readings.
Update2: The fault is continuing to grow, which places it firmly into the 'exactly the same' camp. Some foundations were destroyed but no PGV's yet. The USGS is asleep in their fav. snoozing zone!