hiya i cant beleive such stuff happened i never heard of a gas pipe rupturing and blowing up a neighborhood .people must not have had a chance under such drastic circumstances this is a unusual incident i hope that all will b well and can recover from such a drastic fire and blow up from a ruptured gas main and that everyone can help out

This is, sadly, not an extremely unusual incidence of a gas line exploding. I recall similar tragedies over the past several decades in Washington State and Texas, and other states as well. I live in SE Oregon, where a new natural gas pipeline is now being constructed for some 600 miles, into the state of Wyoming. When I learned of this project these previous disasters popped right up in my mind.

My question is, why are these pipelines running right through a neighborhood of homes and families? --They must have been built when that land was vacant, and then homes were built over them. Who developed that idea, and why in the world was it PERMITTED? --Let me guess: The almighty $$$$$$.

The pipeline "may be 50 years old". What does that mean? That this was, then, to be expected? That maintenance and/or refurbishing is the normal procedure? Is that possible after the area is built up and sold to unsuspecting families?

By the way, residents where I live were merely informed of the new project here, NOT ASKED. As for this immediate area, the project is NOT NEAR human beings. EPA and anthropological safeguard officials are on-site at all times. The some 600 workers temporarily housed here in our little town of Lakeview OR 97630 have been a good source of info regarding the ways required procedures are being enforced. We don't have to rely on the construction co.'s "progress report" in our weekly newspaper, thank goodness --of course, there are no guarantees, anyway.

There's a lump in my throat and tears in my eyes as I write this. Oh, my God; I do so wish your tragedy, and others like it, could have been avoided. Please know that people everywhere are hoping for you recovery and peace.
Sincerely,
Linda-Anne Manley

Just about 60 seconds before the pipeline burst, there was a very small earthquake that hit. It was only 1.1 mag. but it was located only 2000 feet deep and a mile and a half west of the fire (very shallow and close by, but too deep and far away to be the blast itself).

Web Link

Kinda scary that such a tiny earthquake can set off a cracked pipe.

> A 30-inch diameter gas pipe is the likely culprit
> behind the massive explosion that rocked the community at
> 6:15 p.m. Thursday,

As proposed in the previous posting, there seems to have been Magnitude 1.1 earthquake just a couple of minutes before the blast--

Web Link
Magnitude: 1.1
Date-Time: Friday, September 10, 2010 at 01:11:12 UTC
Thursday, September 09, 2010 at 06:11:12 PM at epicenter
Location: 37.623°N, 122.442°W
Depth: 0 km (~0 mile) (poorly constrained)

Region: SAN FRANCISCO BAY AREA, CALIFORNIA

Distances: 1 km (1 miles) WSW (258°) from San Bruno, CA
---

If this is true, and PG&E claims that it is "not responsible", then this will be a $20-$30M disaster that might leave some/all of the homeowners without adequate compensation to rebuild.

This situation also begs the question, is there anyway to pipe gas into a community so that if a trunk line (like this 30-inch pipe) is sheared/crumpled by an earthquake, the likelihood of an explosion is reduced?

Even if pipes are new, as the magnitude of the quake increases, the ability of the pipe to withstand the forces being imposed on in decrease.

What does this mean about preparing for the Big One? Maybe the point won't be to have supplies on hand, but to have a quick escape route out of the area before the inevitable fire storm that will follow the earthquake. It may make the 1906 Great Earthquake and Fire look like a block party.

If the claims that there was a persistent gas smell days before this awful event, it may not matter about the earthquake. PG&E loves to abdicate responsibility for problems, claiming they're not responsible for "acts of God" but if it was leaking prior to the small earthquake, they would likely bear some of the responsibility. The pipe was allegedly 62 years old & could've been replaced sooner.

Channel 7 news reported last night that residents had complained about a gas smell in the air for more than 1 week. PG&E had sent crews out to look for it, but apparently not very effectively.

How long will the investigation take?

There was no earthquake on the nearby San Andreas Fault (Skyline Blvd.) Just look at the USGS google maps of the 1.1 quake, it was the very location of the pipeline which ruptured an hour later.
With low frequency fault slip tremors commonplace (the SAF trace is just a few hundred feet uphill of this residential area) , this tragic event will not be the first in earthquake country.
Quick shut off mechanisms when abnormal pressure drops on these aged main lines are the most cost effective mechanisms for PG&E and So Cal Edison to mitigate collateral damage.
While replacing susceptible steel transmission lines may be a long term goal, we need to be able to more quickly shut down these aged lines when they inevitably rupture.
All readers should have a gas meter shutoff wrench at their own residence to prepare when the next big quake hits the Bay Area. It's not an if, but when. So be prepared.

There may have been automatic sectionalizing valves, but the "Line pack" the gas still in he pipe between valves, will still vent, and this is what fed the flames initially.

Sharon, the investigation may take up to a year.

Regarding the 1.1 earthquake.

Thursday, September 09, 2010 at 06:11:12 PM at epicenter

I've not seen an exact time for the fire, but one article said "a little after 6 PM", so isn't this 1.1 earthquake like the gas main rupturing?

Sometimes the explosions in the quarry near Cupertino register at 2.0 earthquakes.

Alan, are you asking if the earthquake was actually the pipeline rupturing, rather than there being an earthquake, then a rupture?

I heard someone on the news tonight say there are no recorded complaints of a gas smell --

All of you who have smelled gas around Bowdoin Park, need to call PA Utilities AND PG&E and report the smell. And send emails so you leave a trail -- if you do, they won't ignore it now.