Mon Aug 20, 2018 | 02:09
Shake, Rattle and Roll: Cali Braces for the 'Big One'
Sun, 09 May 2010 08:28:34 GMT
Font size :
By Tahereh Ghanaati

Though 2010 is barely five months old, it is already being called the 'Year of the Earthquakes.' Indeed, we have already witnessed over 840 temblors, measuring at least 5 on the Richter scale, with 773 ranging between 5 and 5.9, 61 registering between 6 and 6.9, 5 measuring from 7 to 7.9 and one, in the Maule region of Chile, tipping the scale at a staggering 8.8. The most recent, which occurred in Sumbawa, Indonesia, on May 8, at 3:22 a.m. local time, measured a nerve-jarring 6.1.

This year's events have not only smashed buildings. They have also destroyed human lives. The death toll from these disasters, so far, stands at nearly 250,000 with the January 12 Haiti quake claiming 230,000 lives, Chile's February 27 event slaying 486, the March 8 quake in Turkey killing 51 and the April 14 temblor in China causing 2,183 fatalities.

The frequency and severity of the quakes, following on the heels of the Hollywood disaster blockbuster, '2012', have caused many to wonder if the recent geological upheavals are not a possible a foretaste of worse things to come. Internet buzz is rife with concerns about the future safety of earthquake-prone areas, particularly, California.

Most seismologists, despite the recent alarming chain of events, insist that the recent quakes have been within the normal range and do not indicate an increase in the Earth's seismic activity. At the same time, it might be mentioned that despite their sang-froid, these experts, if pressed, will admit that the seismic energy released by a major quake (such as the ones that occurred in Haiti and Chile this year) can trigger temblors elsewhere - especially within the same network of fault lines. As geophysicist Dr. Michael Blanpied with the US Geological Survey (USGS) pointed out, big earthquakes definitely cause more earthquakes - or aftershocks -- in the same area.

Other experts, however, are beginning to wonder whether large quakes can affect tectonic plates in other parts of the world since major temblors sometimes occur in clusters. The three most devastating quakes of the 20th Century, which took place in Russia (1952), Chile (1960) and Alaska (1964), respectively, all occurred within a 12-year period of time. Moreover, despite their colleagues' allegations to the contrary, some experts maintain that the recent events do not fit into the parameters of the 'norm' and there has actually been an uptick in earthquake activity worldwide since the massive 2004 Indian Ocean temblor (and resulting tsunami) caused the Earth to shift on its axis.

The bottom line is that the scientific community is divided on whether or not the Earth is entering a new phase of increased seismic activity and whether one quake can trigger another in a different part of the world. There is still much to learn about earthquakes and predicting them is by no means an exact science. Some fault lines, however, are known to pose a greater danger than others and seismic hazard assessment maps of well-known fault lines can be used to estimate the probability of a temblor of a certain magnitude occurring at a given place within a certain period of time.

One of the best-known of these fault lines is the 1,300-kilometer-long San Andreas fault. Running lengthwise down the US state of California, the San Andreas forms the boundary between the North American and Pacific tectonic plates. The Pacific plate is slowly slipping northwest, while the adjacent North American continental plate is moving in a southwesterly direction. The slippage of these two plates in opposite directions is causing tremendous stress along the San Andreas, which experts agree will one day be unleashed in a massive earthquake - an event Californians call the 'Big One.'

The recent seeming upsurge in California's quake activity has caused many to speculate as to whether the Big One might be close at hand.

This mega-quake is not just a possibility; nor is it the fabrication of some Hollywood producer's vivid imagination. Despite its having been the subject of countless disaster flicks, it is, according to seismologists, a certainty. In fact, the latest projections reveal that the 'Golden State' has more than a 99 percent chance of experiencing a 6.7 magnitude earthquake within the next 30 years and a 46 percent chance of being subjected to a 7.5 or greater magnitude quake in that same period of time. If the latter were to occur, experts believe it would most likely take place in Southern California.

Dr. Nancy King, a geophysicist with the USGS in Pasadena has been even more specific. She projects that a quake of an estimated 8.0 magnitude will occur along the southern stretch of the San Andreas fault. Moreover, she maintains that this giant temblor is overdue.

Dr. King is not alone in her opinion. A number of other experts have arrived at the same conclusion. The last major earthquake to hit Southern California was the 1857 Fort Tejon temblor, which occurred in the Carrizo Plain section of the San Andreas. With an estimated 7.9 magnitude, the Fort Tejon event is believed to have been the most powerful quake to rock the area in modern times. According to a recent study by the University of California, Irvine, major temblors have occurred in that sector of the San Andreas approximately every 137 years for the past 700 years. Thus the area is overdue another major quake.

Since it is generally conceded that the Big One eventually will hit, we need to know what to expect when it does occur and is California prepared for it? According to a joint study by the USGS and the California Institute of Technology (Caltech), the results will be devastating. Topping the list will be the loss of life. Despite the fact that Los Angeles lies some 60 miles from the San Andreas Fault, the city is built on a basin of deep sediment, which will be shaken strongly, similar to the way Mexico City was rattled during the 1985 Pacific quakes. One of the main reasons why the 1985 events devastated the 'Distrito Federal' can be found in the soil on which the city is built. The Mexican capital, like Los Angeles, was constructed on a deep bed of sediment. (In Mexico City's case, it was a drained lake bed.) Thus, when the Big One hits California, scientists believe that the soil under the 'City of Angels' will shake, rattle and roll in much the same way as the ground shook under Mexico City in 1985. The scientific community has warned that this mega-temblor could cause the ground under Los Angeles to heave, rising and falling as much as 10 to 20 feet. We can only imagine what might occur if such a quake were to hit during 'rush hour.'

Then there is the infrastructure to consider -- all the lines and networks that make civilization possible, such as electric lines, water and sewer lines, fiber optics cables, petroleum and gas pipelines, bridges, dams, roads and railways. A number of these will be broken, and partially - or totally - destroyed. Such an event, in turn, could lead to another potential problem, which could pose a greater danger than the quake, itself. That is the threat of fire.

Ruptured gas lines almost always mean fires. However, if the quake were to occur during the autumn or winter months when the Santa Ana winds whip through the state, the outcome would be an inferno. Wildfires, which always pose a threat during the windy season, reportedly cost California $1 billion a year. Numerous fires caused by ruptured gas lines and fanned by the Santa Ana winds would greatly increase the problem. These wildfires would race towards urban areas, devouring everything in their path - homes, office buildings and people caught in the flaming death traps. The numbers of people caught, would most likely be greater than one might think, because destroyed highways and roads would hinder escape. Therefore, countless numbers of people would be helplessly trapped in harm's way. It might also be mentioned that these wildfires would rage virtually unimpeded, as destroyed roads and water lines would make fighting them difficult.

The above-mentioned scenario is only a minute portion of what California - and the United States -- can expect when the Big One hits. We have not even addressed what the disaster will do to the US military. The army maintains 3 bases in California, the US Navy and Marine Corps have 12 and the US Air Force, 5. Many of these bases are located in Southern California and San Diego is home to one-third of the US Navy's Pacific Fleet. Needless to say, a major quake will cause the US military major damages. Then there is the Los Angeles film industry to consider and the Port of Los Angeles, which is a major port of trade.

We cannot imagine how extensive the damage will be. We only know it will be bad. And when dealing with Mother Nature, to be forewarned does not necessarily mean to be forearmed.

Your Name
Your Comment
Enter the code shown
terms of use

  • last 24 hours
  • last week
  • last month
© 2009 Press TV. All rights reserved.