Some Early 20th Century Earthquakes in Los Angeles Area Might Have Been Man-Made

Release Date: NOVEMBER 1, 2016

A new study from the USGS suggests that some early 20th century earthquakes in southern California might have been induced (man-made) by past practices that were used by the oil and gas industry.

A new study from the USGS suggests that some early 20th century earthquakes in southern California might have been induced (man-made) by past practices that were used by the oil and gas industry.

In the new study, scientists evaluated the likely cause of several significant earthquakes within the Los Angeles Basin between 1900 and 1933, together with consideration of available oil industry records over this period.

They found that several damaging earthquakes, including a 1929 event near Whittier, California (estimated magnitude 5) and the 1933 Long Beach earthquake (magnitude 6.4) might have been induced by oil and/or gas production during the early decades of the Los Angeles-area oil boom. During the early decades of the oil boom, withdrawal of oil was not balanced by injection of fluids, in some cases leading to dramatic ground subsidence, and potentially perturbing the sub-surface stress field on nearby faults.

In the middle of the 20th century, so-called water-flooding techniques were increasingly employed to compensate for oil withdrawal and to increase production of fields that were becoming depleted. Because industry practices have changed, the results of this study do not necessarily imply a high likelihood of induced earthquakes at the present time.

“It has been widely assumed that induced earthquakes do not contribute significantly to hazard in regions west of the Rocky Mountains, but our research suggests that damaging induced earthquakes might have occurred in the past, ” said Susan Hough, USGS seismologist. “Our study further suggests that the rate of natural tectonic earthquakes in the Los Angeles basin for this time period might have been lower than previously estimated.”

Earthquake rates have increased sharply in recent years in some parts of the United States, including in Oklahoma, where earthquakes were formerly infrequent. Extensive past research has supported the conclusion that much of this increase is due to disposal of wastewater into deep geologic formations.

The study, “Potentially induced earthquakes during the early 20th century in the Los Angeles Basin,” was published Nov. 1 in the Bulletin of the Seismological Society of America.


Department of the Interior,
U.S. Geological Survey

Office of Communications and Publishing
12201 Sunrise Valley Drive
Reston, VA 20192
United States
Phone: 703-648-4460

Public Affairs Specialist
Western States
Phone: 626-583-7811


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Comment by Martin Harris on December 10, 2016 at 8:55

Got to wonder what's under there now? Another Love Canal in the making?

Comment by rose on December 10, 2016 at 7:59

Thanks Lee - blows my mind that folk live all over this area now.  I can only imagine the contamination to the infrastructure of Long Beach.

Comment by Lee Jun-fan on December 9, 2016 at 17:16

I found this online, great article on the past and present oil production in LA.

Comment by Baza aka Alien Strawman Matrix on December 8, 2016 at 21:39

Glad the info has been useful Martin. I was amazed by Lee's photo of Signal hill. Just looked on google & it is totally urbanised. It would be interesting to know cancer rates here relative to other areas with a lesser history of pollution. Even then making a mess was takin care of b'ness. Now messing with Chch & Kaikoura is no different. My look at USGS was driven by what I read as a major lack of transparency by Geonet only showing a limited number of quakes with previous days disappearing, making it hard to see a trend. Trying to collate with the seismic vessel position is impossible. Most of the quakes seem to be signature ones of Mag 3 & shallow up to 10km so why am I suprised? 

Comment by Martin Harris on December 8, 2016 at 20:47

One thing I disagree with in this item: the liquid injection method that supposedly reduces the possibility of seismic activity, actually lubricates cracks and faults and can facilitate the onset of seismic activity, which is why so many quakes are associated with injection wells.

Comment by Martin Harris on December 8, 2016 at 20:22

Thank you Baza.

I will copy this one to Uncensored. Just the kind of ammunition I like to keep handy when dealing with Big Oil shills.

Thanks also to Lee Jun for the historic photo which I nicked to illustrate the article.

Published now:

Comment by Lee Jun-fan on December 7, 2016 at 17:06

Image result for california oil fields

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