It was not a good wake up call this morning.
Actually, that little 4.9 wake up call could have been an indication of this event starting to wind down.
Don't get me wrong, I understand that this series will go on for at least months, and more probably years. However, that little 4.9 might have signified the start of the wind down for this initial swarm. The following is my take on things, and keep in mind that as a seismologist I am a pretty good electronics engineer. In other words, I don't know squat about seismology, so this is my untrained laymens view, and could easily be a case of a I don't know what I don't know.
Since the first day of the swarm our aftershock rate (events per hour) appears to have been steadily increasing. The way I understand it, normally, after the main shock, the aftershock rate deteriorates at a pretty easy to see rate. But that really has not been happening.
24 hours after the first event, and before the 7.1, we had roughly (all numbers given are rough) 1150 seismic events, preshocks of all sizes. 10 hours later the 7.1 hit, so everything after that is an aftershock. In the second 24 hour period (2nd day) we had about 1300 aftershocks. The 3rd day we had about 1300 aftershocks. The 4th day we had about 1200 aftershocks. The 5th day we had 1625 aftershocks. The 6th day about 1750 aftershocks (at one point, for several hours, we were on path for 1900+ in 24 hours). The 7th day we had about 1550 aftershocks. These are pretty flat numbers for about 3 days.
Then the 4.9 hit, the largest aftershock since shortly after the main shock.
Since then we have been in a steady decline in activity. The morning of 8th day we pulled about 1100 aftershocks in the preceding 24 hours. The morning of the 9th day we were at about the 900 aftershock per 24 hours. Right now, the evening of the 9th day, we are at about 775 aftershocks in the last 24 hours.
The activity is definitely trending downwards now. Fewer events, and smaller events. And that trend really started about the time we had that 4.9.
We are going to have more, there will be more high 4's, and I would not be surprised if a 5 or two did not pop up. But, at least on paper and to this untrained observer, things do seem to be calming down.
T!