The Long Beach Earthquake 1933
Widespread Damage to Buildings and Schools in Southern California
May 20, 2009
Long Beach, California is located on the Newport-Inglewood Fault line that extends on land from Newport Beach to Culver City. Parts of the fault line are easily recognizable as a chain of small hills stretching between Signal Hill and Culver City. The fault line follows the coastline south of Signal Hill and then heads offshore south of Newport Bay.
The Newport-Inglewood is a strike-slip fault and continues to slip laterally, but only less than one inch every year. The rupture of this fault line caused the recent Inglewood Earthquake in California on May 17, 2009.
Events of the 1933 Long Beach Earthquake
An intense foreshock occurred near Huntington Beach on March 9th, the day before the Long Beach Earthquake and that was the only warning sign.
According to the Southern California Earthquake Center:
“At 5:54 p.m., March 10, 1933, southern California experienced its deadliest seismic disaster in recorded history when a magnitude 6.4 earthquake struck the Long Beach area. The Long Beach earthquake occurred along the Newport-Inglewood fault zone centered off the coast of Newport Beach, with a hypo-central depth of 10 kilometers. “
Long Beach and Compton suffered the worst damage. This was due to a large amount of landfill in the area plus sandy soil, which caused liquefaction. Along the coast between Long Beach and Newport Beach, the landfill in marshy areas became unstable. Highways and bridges were impassable.
Buildings were poorly designed in that era. Many structures were made out of brick but without any reinforcement. In Compton, almost every building in a three-block radius suffered extensive damage. Buildings in Long Beach were shaken off their foundations, some collapsed and others had fallen chimneys.
School buildings seemed to be the worst hit, especially in Long Beach. The architecture was not designed to withstand earthquakes. Many schools were built with ornate towers at the entrance that instantly tumbled from the movement of the ground. If the earthquake had occurred two hours earlier, the children would have still been at school.
Several fires broke out in Long Beach due to broken gas lines and water lines were severed. Oil derricks near Huntington Beach were rattled out of the ground. A water tank ruptured in Los Angeles and just over five million gallons of water poured out.
The State of California, Dept of Conservation reported the final figures of death toll and damages:
“The earthquake caused extensive damage (approximately $50 million, 1933 dollars) throughout Long Beach and surrounding communities. Damage was most significant to poorly designed and unreinforced brick structures. The earthquake caused 120 fatalities. Within a few seconds, 120 schools in the Long Beach area were damaged, of which 70 were destroyed.”
What was Learned From the 1933 Long Beach Earthquake
The earthquake proved a need to make schools more earthquake resistant by requiring reinforcement of masonry structures. One month later, on April 10th 1933, the Field Act was passed. It was named after Charles Field, a member of the California Assembly, who was instrumental in getting the laws changed.
As a result, all school plans, specifications and construction had to be authorized and supervised by the Division of Architecture of the California State Department of Works. The Field Act did not cover schools built prior to 1933 but six years later, the Garrison Act was passed to enforce construction regulations on these schools.
The Long Beach Earthquake was the first earthquake to provide the opportunity for the Seismological Laboratory at the California Institute of Technology in Pasadena to analyze data in great detail.
The 1933 earthquake also provided information to structural engineers as to what building designs and materials could or could not withstand earthquakes. Many of their findings have formed the basis of California building codes.
Related Articles on California Earthquakes:
1989 San Francisco Earthquake; Also Known as the Loma Prieta or World Series Quake. A television broadcast of the World Series at Candlestick Park in San Francisco quickly became a live news report of an earthquake.
1906 San Francisco Earthquake: Quake in Bay Area Among Worst Natural Disasters Recorded in the US. A severe rupture occurred along the San Andreas Fault near San Francisco and tremors were felt in Oregon, southern California and central Nevada.
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