Redhart Fri 10 Sep 2010, 8:23 pm
Here is the USGS recording of the explosion.
http://earthquake.usgs.gov/earthquakes/recenteqsus/Quakes/nc71453305.html#summaryI do believe the most probable explanation is a gasline explosion at this point. And yes, they can do what was done last night. There have been other instances where a high-pressure, large gasline has exploded with deadly and catastrophic results like this.
Reports from all kinds of media have been saying that residents of the area have been calling PG&E about a gas smell for the last three weeks. PG&E did respond and came out and checked on it...but no one was given the results of their check and if they found anything.
You can bet there will be an investigation of what was found, how they searched for the cause and how this tragedy manifested.
According to Kate Hutton of the USGS, there is little evidence that an earth shift was involved (although she is the one that passed along the link for the explosion recording on seismometers). There is no data that would support it at this time (but she leaves it open for investigation of the area to see what they find in a physical investigation).
My guess is we are looking at an infrastructure failure of terrible magnitude, much like the bridge in the midwest, rather than a natural phenomenon.
And yes, the NTSA is in charge of investigating pipeline accidents as well as air safety, btw. They always have been. This is not unusual.
I know I will be keeping an eye and ear out for further findings when they finally are able to get in there and see what the heck happened.