PROBABILITY: THE UNCERTAINTY FACTOR IN SCIENCE -- SCIENTISTS CLAIM 1,000-YEAR EARTHQUAKE LULL IN LOS ANGELES -- INDICATOR OF INCREASED RISK?
GREAT! Days after posting my blog entry questioning the safety of some of the welded steel moment frame (WSMF) high-rise buildings which experienced various degrees of failure in the Northridge Quake of 1994 and in which I noted that the famed seismologist Lucy Jones, of the United States Geological Survey, said that the Andreas Fault/San Jacinto fault area was 300 years overdue for a massive quake, we get another earthquake study affecting the Southern California region.
This time from the scientists at USC (University of Southern California) who now claim that there may be a link connecting the desert areas (which are experiencing more quakes) and the Los Angeles basin which is experiencing less quakes than would be predicted by the statistical analysis of historical records.
According to USC College Professor, James Dolan, "Earthquakes under the basin at historic low." "The Los Angeles basin appears to be in a seismic 'lull' characterized by relatively smaller and infrequent earthquakes, according to a study in the September issue of Geology.
By contrast, the Mojave Desert is in a seismically active period. Seismic activity alternates between the two regions, the study suggests. According to their findings, "the lull in the Los Angeles basin began 1,000 years ago.
“'The past 1,000 years has been relatively quiet,' Dolan said, referring to what he calls the 'urban fault network' under the Los Angeles metropolitan area."
Dolan said that even the Northridge earthquake of 1994, the costliest natural disaster in U.S. history at the time, was 'a drop in the bucket' compared to the massive jolts that would strike the basin during a period of high seismic activity."
Of course, the authors are quick to supply the caveats:
• The urban fault network does not include the more distant San Andreas fault. Though the San Andreas is storing energy at a slower than average rate, a major quake along the fault is always possible. About 10 San Andreas “big ones” have occurred during the current lull on the urban fault network.
The authors developed their theory from the discovery of several “clusters” of intense seismic activity in the geological record. It is not yet known if the clusters are statistically significant.
The authors studied the geological record going back 12,000 years. During that period, they found several clusters of seismic “bursts,” with the most recent lasting 4,000 years and ending about 1,000 years ago. The seismic clusters were separated by periods of relative calm lasting about 1,500 to 2,000 years.
Remarkably, the lulls in the Los Angeles region corresponded with seismic clusters in the Mojave Desert, as described in 2000 by Thomas Rockwell of San Diego State University and his colleagues.
Which leads to Dolan's unproven phenomenological semi-empirical conclusion that:
“When we're having earthquakes in L.A., generally we don't have as many earthquakes in the Mojave,” and vice versa, Dolan said.
The study in Geology proposes a mechanism by which periods of high seismic activity alternate between the urban fault network and the Mojave Desert.
“Nullius in verba”-- take nobody's word for it!
"Acta non verba" -- actions not words
“Beware of false knowledge; it is more dangerous than ignorance.”-- George Bernard Shaw
“Progressive, liberal, Socialist, Marxist, Democratic Socialist -- they are all COMMUNISTS.”
“The key to fighting the craziness of the progressives is to hold them responsible for their actions, not their intentions.” – OCS "The object in life is not to be on the side of the majority, but to escape finding oneself in the ranks of the insane." -- Marcus Aurelius “A people that elect corrupt politicians, imposters, thieves, and traitors are not victims... but accomplices” -- George Orwell “Fere libenter homines id quod volunt credunt." (The people gladly believe what they wish to.) ~Julius Caesar “Describing the problem is quite different from knowing the solution. Except in politics." ~ OCS
