Monday, March 10, 2014

On This Date: The 1933 Long Beach Earthquake

LONG BEACH - On Sunday night a magnitude 6.8 earthquake struck about 50 miles west of Eureka in the Pacific Ocean, according to the United States Geological Survey, and it was felt throughout much of the Northern California and southern Oregon. With this earthquake being some distance from land there was not much damage.

Sunday night's earthquake struck at 10:18 p.m., and was under a couple hours shy of occurring on March 10, which is the anniversary of a much less powerful earthquake that also had an epicenter in the Pacific Ocean, but caused much severe damage.

On March 10, 1933, at 5:54 p.m. with a magnitude 6.4 the deadliest earthquake in Southern California history on record hit resulting in 120 reported deaths and caused, in 2014 dollars, $899,676,923 worth of damage.

Commonly referred to as the Long Beach Earthquake, as damage was great in Long Beach and Compton with many collapsed buildings, the epicenter of this earthquake was actually about a mile west of Newport Beach in the Pacific Ocean.

 photo Compton.jpg
Aftermath of the 1933 earthquake along Main Street in Compton.  No copyright infringement intended; shown for historic and educational purposes only.   

As Carey McWilliams would point out, many boosters and chamber of commerce types often sold Southern California, aside from being the land of sunshine and oranges, as a place where big earthquakes do not ever happen, despite the fact that within the last 34 years leading up to 1933 there were at least three notable earthquakes in Southern California. Of course much of the same was said and done in San Francisco before and after the 1906 earthquake with their boosters claiming it was just a great fire that destroyed most of San Francisco in 1906 and ignoring large quakes in the Bay Area prior to 1906.

Nonetheless this earthquake was really the first event that brought to light many hazards and potential hazards earthquakes pose to modern Southern California.

With so many collapsed buildings the most important thing to come from the 1933 earthquake was a piece of legislation called, The Field Act. The Field Act was the first major piece of legislation that mandated earthquake resistant construction, which was specifically aimed for schools. When this earthquake struck many schools collapsed due mainly to unreinforced masonry construction, and, as has been pointed out many times over and still worth repeating, had this earthquake struck just a few hours earlier many, perhaps hundreds, of school children likely would have perished. Records show at least 250 schools were destroyed in this earthquake.

 photo old_thomas_jefferson_jh.gif
Severe damage at Thomas Jefferson Junior High School in Long Beach as a result of the 1933 earthquake. No copyright infringement intended; shown for historic and educational purposes only.

The 1933 earthquake then and now vividly shows the dangers the Newport-Inglewood Fault poses to the Los Angeles basin. Many geologists and seismologists believe this fault can produce a magnitude 7.4 earthquake, and that such a major event on this fault could be much worse in terms of damage and casualties in L.A. and Orange County than perhaps an event on the San Andreas Fault.

With its epicenter just off the coast in Newport Beach this quake still holds the record as being the most deadly and damaging earthquake in Orange County history with major damage in Santa Ana, Garden Grove and Anaheim.

 photo 1933longbeachP061.jpg
Damage to a Santa Ana building as a result of the 1933 earthquake. No copyright infringement intended; shown for historic and educational purposes only.   

Historic film footage of the aftermath of the Long Beach Earthquake. No copyright infringement intended; shown for historic and educational purposes only.

A very important lesson we should all take from this earthquake is that it should dispel the myth that big earthquakes in Southern California only occur in the middle of the night or early morning. For anybody who grew up or lived in the Southern California for the past 25-plus years probably know that our major earthquakes have occurred during the early morning hours, and this has lead some people to believe big quakes only hit around that time. As USGS and other scientists have stressed many times over, it is simply luck that Southern California's recent large earthquakes have hit in the early morning. Seismologists and emergency planners stress that a major earthquake could hit at anytime, as this one did in 1933 at 5:54 p.m.

As old photographs show the Southern California coast, particularly in the Huntington Beach area, used to be dotted with oil wells. It was reported about two hours before the earthquake the pressure in Huntington Beach oil wells dropped. Geologists and seismologists have studied pressure drops in oil wells before and after earthquakes, but however at this time the whole correlation and causation of pressure drops and earthquakes has not added up, so to speak.

It would not be until the 1971 Sylmar Earthquake that the L.A. basin would experience its next damaging and deadly earthquake, and not until the 1952 Kern County Earthquakes that California would have its next damaging and deadly earthquake.

The Newport-Inglewood Fault is still highly active, and was likely responsible for the May 17, 2009 M4.7 earthquake near Inglewood. This fault may possibly be responsible for the series of minor earthquakes in and around the Marina Del Rey area within the last year and a half.

In very modern times the Newport-Inglewood Fault made it presence known in Orange County when on April 7, 1989 a M4.7 occurred right under Newport Beach. That quake caused items to fall off shelves at the Newport Beach Fashion Center and other such property damage around Orange County. It was the last notable sized earthquake in Orange County.

There is that whole thing about history and learning from the past, and not repeating it. Sometimes earthquakes have a tendency to strike the same area twice or more and that cannot be helped, but to avoid mistakes of the past we can all be prepared.

The 1933 earthquake shows big quakes can hit in the middle of rush hour, and an earthquake of this size with its Newport Beach epicenter can and likely will cause damage in the L.A. and O.C. metro area. Any time an earthquake at or above magnitude 6 hits in an urban area that is when you can expect damage, even in an area that is suppose to be "built" to resist quake damage.

As we always do when we talk about earthquakes on this site we stress the importance of being prepared, and remember, that at this time there is no way to predict earthquakes.

1 comment:

  1. I have for a price several hands full of original black and white photos of the 1933 earthquake taken the Long Beach area... If interested: