Accessibility/Mobile Features
Skip Navigation
Skip to Content
Editorial News
Lifestyles
Classified Sites

The Canadian Press - ONLINE EDITION

Study says irrigation efforts in California's Central Valley can stress San Andreas Fault

FILE - This 2007 aerial file photo provided by United States Geological Survey, shows a view looking southeast along the surface trace of the San Andreas fault in the Carrizo Plain area of California. A study released Wednesday, May 14, 2014 by the journal Nature suggests excessive groundwater pumping for irrigation in California's agricultural belt can stress the San Andreas Fault, potentially creating future earthquakes. (AP Photo/U.S. Geological Survey, Scott Haefner)

Enlarge Image

FILE - This 2007 aerial file photo provided by United States Geological Survey, shows a view looking southeast along the surface trace of the San Andreas fault in the Carrizo Plain area of California. A study released Wednesday, May 14, 2014 by the journal Nature suggests excessive groundwater pumping for irrigation in California's agricultural belt can stress the San Andreas Fault, potentially creating future earthquakes. (AP Photo/U.S. Geological Survey, Scott Haefner)

LOS ANGELES, Calif. - Excessive groundwater pumping for irrigation in California's agricultural belt can stress the San Andreas Fault, potentially increasing the risk of future small earthquakes, a new study suggests.

The fault is responsible for some of the most devastating seismic disasters in state history, including the 1906 San Francisco earthquake that reduced much of the city to rubble.

GPS readings found parts of the San Joaquin Valley floor have been sinking for decades through groundwater depletion while the surrounding mountains are being uplifted. This motion produces slight stress changes on the San Andreas and neighbouring faults.

"The magnitude of these stress changes is exceedingly small compared to the stresses relieved during a large earthquake," lead researcher Colin Amos, a geologist at Western Washington University, said in an email.

The findings were released Wednesday by the journal Nature.

The study suggests that human activities "can cause significant unclamping of the nearby San Andreas Fault system" through flexing of the Earth's crust and upper mantle, Paul Lundgren of the NASA Jet Propulsion Laboratory wrote in an accompanying editorial. Lundgren had no role in the research.

The ongoing drought is expected to exacerbate the problem as communities tap groundwater faster than it can be replenished. As the valley subsides, this change in load causes the Sierra Nevada and Coast ranges to slowly rise.

Since the San Andreas runs parallel to the valley, scientists said this upward flexing of the surrounding land can trigger small quakes. However, it's unclear whether long-term stresses from groundwater extraction have any bearing on future large earthquakes on the fault.

"These earthquakes are likely to occur no matter what humans do," Amos said.

The San Andreas is the most significant fault crisscrossing California. Nearly 800 miles (1,300 kilometres) long, it stretches from a peninsula north of San Francisco to the Salton Sea near the U.S.-Mexico border.

Scientists have said a magnitude-7.8 event on the southern San Andreas — a so-called Big One — could kill 1,800 people and cause $200 billion in damage.

For the past several years, the state has held preparedness drills designed to help residents cope with strong shaking.

  • Rate this Rate This Star Icon
  • This article has not yet been rated.
  • We want you to tell us what you think of our articles. If the story moves you, compels you to act or tells you something you didn’t know, mark it high. If you thought it was well written, do the same. If it doesn’t meet your standards, mark it accordingly.

    You can also register and/or login to the site and join the conversation by leaving a comment.

    Rate it yourself by rolling over the stars and clicking when you reach your desired rating. We want you to tell us what you think of our articles. If the story moves you, compels you to act or tells you something you didn’t know, mark it high.

Sort by: Newest to Oldest | Oldest to Newest | Most Popular 0 Commentscomment icon

You can comment on most stories on brandonsun.com. You can also agree or disagree with other comments. All you need to do is register and/or login and you can join the conversation and give your feedback.

There are no comments at the moment. Be the first to post a comment below.

Post Your Commentcomment icon

Comment
  • You have characters left

The Brandon Sun does not necessarily endorse any of the views posted. Comments are moderated before publication. By submitting your comment, you agree to our Terms and Conditions. New to commenting? Check out our Frequently Asked Questions.

letters

Make text: Larger | Smaller

Brandon Sun Business Directory
Sudden Surge: Flood of 2014
Opportunity Magazine — The Bakken
Why Not Minot?
Welcome to Winnipeg

Social Media