Unfortunately there still is no scientifically proven predictor of an impending earthquake. The foul odors today here in the Los Angeles area cannot be scientifically or reasonably assumed to indicate an impending major earthquake. However that does not rule out a major earthquake occurring soon.
If a major earthquake were to occur in the area in the next 48 hours, it's still unlikely that the bad odor could in retrospect be proven to have been a predictive indicator. Prior to the 1994 Northridge earthquake, the 1989 Loma Prieta earthquake in San Francisco and the 1971 Sylmar (Los Angeles) earthquake, there were no unusual odors noticed or reported prior to any of the earthquakes.
Seismologists and now local authorities remind us that colorless, odorless and carcinogenic radon gas is released prior to and at the time of a fault-line rupture. Some believe that radon emission may account for unusual behavior noticed in small animals prior to some earthquakes.
Sulfuric odors have been noticed as recently as March 2012 near the Madrid Fault Line, which some bloggers believed meant an impending major earthquake. A major earthquake on the Madrid Fault Line still has not happened, however.
In 2011 some San Diego residents noticed strong chemical odors near a beach and feared a major earthquake which also has not happened.
Venezuelan residents in August this year noticed a strong odor of sulfur hours prior to the tragic explosion at a local refinery. That explosion has been reported to have been caused by a gas leak.
Survivors: Strong gas odor before Venezuela blast
On Line: 26 August 2012 15:54
In Print: Monday 27 August 2012
PUNTO FIJO, Venezuela (AP) — Venezuelans who live next to the country's biggest oil refinery said they smelled a strong odor of sulfur hours before a gas leak ignited in an explosion that killed at least 39 people and injured more than 80.
The Amuay refinery was still burning on Sunday more than a day after the blast, sending up a thick column of black smoke.
Residents in a neighborhood next to the refinery said that starting about 7 p.m. on Friday they noticed the unusually strong odor. Government officials say the blast occurred about 1:15 a.m. on Saturday when the gas leak created a cloud that ignited.
The cause of the disaster is under investigation.
Gabriela Nunez, a housewife who lives near the refinery, said she noticed the gas odor on Friday night, and then hours later came the shock wave...
End of excerpt. Story continues here: Survivors: Strong gas odor before Venezuela blast
Below describes a little of what Caltech, U.C. Berkeley and the USGS have been working on in order to predict earthquakes and create an early warning system.
An earthquake early warning system can provide a few seconds to tens of seconds warning prior to ground shaking during an earthquake. The warning messages can be used to reduce damage, costs and casualties in an earthquake. Earthquake early warning systems are currently operating in Mexico, Taiwan and Japan, but not in the United States. In California, the California Integrated Seismic Network (CISN) is testing an early warning system, using its real-time operations.A CISN early warning test system caught the M 5.4 Alum Rock earthquake of 2007. This map shows the distribution of ground shaking intensity predicted using the first few seconds of data recorded by seismometers near the epicenter in San Jose. The data used to generate this map was available a few seconds before the shaking was felt in San Francisco.
How does Earthquake Early Warning work?
The objective of earthquake early warning is to rapidly detect the initiation of an earthquake, estimate the level of ground shaking to be expected, and issue a warning before significant ground shaking starts. This can be done by detecting the first energy to radiate from an earthquake, the P-wave energy, which rarely causes damage. Using P-wave information, we first estimate the location and the magnitude of the earthquake. We use this to estimate the anticipated ground shaking across the region to be affected. The method can provide warning before the S-wave, which brings the strong shaking that usually causes most of the damage, arrives.
Feasibility studies of earthquake early warning methods in California have shown that the warning time would range from a few seconds to a few tens of seconds, depending on the distance to the epicenter of the
Earthquake Early Warning
Late in 2007, MHDP participated in discussion with Caltech, U.C. Berkeley, and the USGS to create an Earthquake Early Warning System. As contributors and end-users have considered the results of the ShakeOut Scenario, the discussion about earthquake early warning has been re-engaged, in examining how it might mitigate injury, property damage, and the loss of life in the ShakeOut earthquake.
Currently, work is being done in partnership with the California Integrated Seismic Network (CISN) to develop the tools and algorithms to provide a warning that an earthquake is underway and strong shaking will reach you based on your distance from the fault rupture...
End of excerpt. Article continues here: Earthquake Early Warning
