Now for something a little different-some people opposing a huge development at Playa del Rey (Los Angeles coast) had my card and asked if I would look at the geology part....Since I've been working just offshore and want to get better young stratigraphic control from onshore to offshore, I said I'd look at the Environmental Impact Report-because that was an easy way to get the EIR. There had been a previously-interpreted 2 shallow faults through the site (in that area, shallow would mean active because the strata are young there...). Consultants looked at this-did 3D seismic, lines of coreholes, and they concluded there was probably no fault. Other consultants showed that there were high levels of gas near the surface (mostly methane). The irresponsibly/incompetently stated that you had to have an active fault to get this deeply-sources gas to the surface. This is just not true-you only need permeable pathways. There is a gas-rich layer either 50 feet or 50 m below the surface-a gravel layer where gas would flow easily. This would have to be mitigated with shallow wells and monitoring if they build there. The site is within a few km of some active faults like the Santa Monica and Newport Inglewood. It is above the proposed Compton thrust, which I (with cause) believe exists and is active. So, like probably virtually anywhere in LA basin, the site is subject to strong ground motion. The people opposed to the project hoped to use the possibility of a catastrophic release of gas, suggested by the not-so-with-it consultants, during an earthquake. The opponents suggested that this could come from a gas storage project. But, in my quick read the gas storage is in an old oil field, in a sand layer 1 1/2 km down, and I just don't believe that this would come shooting out during a quake. But, I'd like some comment (and references if you have them) on whether there could be a big release of gas from shallow sources. This is very likely the case in Santa Barbara Channel during undersea landslides. My wife is working in Gulf Of Izmit in Turkey, and now things the lumpy seafloor is due to large gas release during the 1999 quake. Lowell Whiteside has posted here about heat/flames /gas (I forget exactly) during the 1999 quake and also, I think, a much older quake in, I think, Chile. But, what about onshore? There are some strata at the site subject to liquefaction. Los Angeles basin, according to a 1991 book, is the most oil-rich basin in the world for its volume (Saudi Arabia field is much larger, for example).
So, Canie, you have something else to worry about than tsunamis-like bursting into flame. Gee, its good I'm semi-anonymous so I can make irresponsible comments like that!
Chris