Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Research finds human impact may cause Sierra Nevada to rise, increase seismicity of San Andreas Fault

16.05.2014

University of Nevada, Reno researchers go to science conference in Vienna to present findings

Like a detective story with twists and turns in the plot, scientists at the University of Nevada, Reno are unfolding a story about the rapid uplift of the famous 400-mile long Sierra Nevada mountain range of California and Nevada.


This photo shows the approximate location of maximum subsidence in the United States, identified by research efforts of Dr. Joseph F. Poland (pictured). The site is in the San Joaquin Valley southwest of Mendota, Calif. Signs on the pole show approximate altitude of land surface in 1925, 1955, and 1977. Scientists have now found that the groundwater depletion has contributed to rapid uplift of the Sierra Nevada mountains and the California Coast Range as well as affected seismic activity on the San Andreas Fault.

Credit: Photo Courtesy USGS.

The newest chapter of the research is being published today in the scientific journal Nature, showing that draining of the aquifer for agricultural irrigation in California's Central Valley results in upward flexing of the earth's surface and the surrounding mountains due to the loss of mass within the valley. The groundwater subsidence was found to also correlate with seismic activity on the San Andreas Fault.

University of Nevada, Reno Research Professor Geoff Blewitt also told the story in a presentation at the European Geophysical Sciences Union conference in Vienna, Austria on April 28. The annual EGU General Assembly is the largest and most prominent European geosciences event. It attracts over 11,000 scientists from all over the world.

"We first wrote two years ago about the rapid rise of the Sierra, with its 14,000-foot peaks in the south and 10,000-foot peaks at Lake Tahoe, moving as much as 1 to 3 millimeters per year," said Blewitt, of the Nevada Bureau of Mines and Geology, a division of the College of Science. "The puzzling results of our earlier research cannot be explained easily by geology alone. We've now found that a reason for the rapid uplift may be linked to human activity."

Over the past 150 years, around 40 trillion gallons of groundwater in California's Central Valley has been lost through pumping, irrigation and evapotranspiration. That's roughly equal to all the water in Lake Tahoe, the volume of which can cover the entire state of California in 14 inches of water.

"This massive withdrawal of water has relieved pressure on the Earth's crust, which is now rebounding upwards in response," Blewitt said. "This is counter-intuitive to most people, even geologists, who tend to only think that water withdrawal causes subsidence, which is only true in the sediments of the valley from which the water is withdrawn. With the weight of the groundwater missing, the hard-rock crust under the valley is actually rising too."

The rise is quite fast in geologic time, with these mountain ranges rising by a similar amount each year – about the thickness of a dime – with a cumulative rise over the past 150 years of up to 6 inches, according to the calculations by the team of geophysicists.

Blewitt and colleague Bill Hammond, who run the Nevada Geodetic Laboratory at the University of Nevada, Reno, partnered with the University of Western Washington, the University of California, Berkeley and the University of Ottawa in the research.

"The real importance of this research is that we are demonstrating a potential link between human activity and deformation of the solid Earth, which explains current mountain uplift and the yearly variation in seismicity," said Colin Amos, assistant professor of geology from Western Washington University and lead author of the Nature article. "These are questions that lots of geologists have been puzzling over, and it's a real eye opener to think that humans are the ultimate cause."

The study is based on detailed GPS measurements from California and Nevada between 2007 and 2010. Also working on the study were Pascal Audet of the University of Ottawa and Roland Bürgmann, professor of earth and planetary science at the University of California, Berkeley. The detailed GPS analysis was performed by Hammond and Blewitt with support from the National Science Foundation.

Hammond and Blewitt use data from their Nevada Geodetic Lab and its MAGNET GPS Network, the largest GPS data-processing center in the world, able to process information from about 12,000 stations around the globe continuously, 24/7. The facility measures the shape of the Earth every day using data drawn in from the global network with stations on every continent around the planet, including more than 1,200 stations from the NSF EarthScope Plate Boundary Observatory, as well as stations in space. The space-based radar data comes from the European Space Agency with support from NASA.

"We can sense the long-term flexing of the crust that accompanies trends in climate and related seasonal changes in the Earth's surface that track yearly precipitation," Hammond said. "The processing facility at the Nevada Geodetic Laboratory makes it possible to interpret trends in over 500 locations in southern California, needed to measure the centimeter-scale changes these loads produce. It makes it possible for scientists to connect climatic changes to subsidence patterns and the rate of earthquake occurrence."

"The data is like a gold mine, we keep digging for new discoveries," he said. "Scientists around the world use it extensively for research such as modeling earthquakes and volcanoes."

###

The article in Nature, "Uplift and seismicity driven by groundwater depletion in central California," can be found online at http://www.nature.com.

For the Nevada Geodetic Laboratory and geodetic information go to http://geodesy.unr.edu/index.php.

Mike Wolterbeek | Eurek Alert!

Further reports about: Earth GPS Geodetic Nevada Sierra Nevada activity earthquake evapotranspiration rise withdrawal

More articles from Earth Sciences:

nachricht Researchers find higher than expected carbon emissions from inland waterways
25.05.2016 | Washington State University

nachricht Rutgers scientists help create world's largest coral gene database
24.05.2016 | Rutgers University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Worldwide Success of Tyrolean Wastewater Treatment Technology

A biological and energy-efficient process, developed and patented by the University of Innsbruck, converts nitrogen compounds in wastewater treatment facilities into harmless atmospheric nitrogen gas. This innovative technology is now being refined and marketed jointly with the United States’ DC Water and Sewer Authority (DC Water). The largest DEMON®-system in a wastewater treatment plant is currently being built in Washington, DC.

The DEMON®-system was developed and patented by the University of Innsbruck 11 years ago. Today this successful technology has been implemented in about 70...

Im Focus: Computational high-throughput screening finds hard magnets containing less rare earth elements

Permanent magnets are very important for technologies of the future like electromobility and renewable energy, and rare earth elements (REE) are necessary for their manufacture. The Fraunhofer Institute for Mechanics of Materials IWM in Freiburg, Germany, has now succeeded in identifying promising approaches and materials for new permanent magnets through use of an in-house simulation process based on high-throughput screening (HTS). The team was able to improve magnetic properties this way and at the same time replaced REE with elements that are less expensive and readily available. The results were published in the online technical journal “Scientific Reports”.

The starting point for IWM researchers Wolfgang Körner, Georg Krugel, and Christian Elsässer was a neodymium-iron-nitrogen compound based on a type of...

Im Focus: Atomic precision: technologies for the next-but-one generation of microchips

In the Beyond EUV project, the Fraunhofer Institutes for Laser Technology ILT in Aachen and for Applied Optics and Precision Engineering IOF in Jena are developing key technologies for the manufacture of a new generation of microchips using EUV radiation at a wavelength of 6.7 nm. The resulting structures are barely thicker than single atoms, and they make it possible to produce extremely integrated circuits for such items as wearables or mind-controlled prosthetic limbs.

In 1965 Gordon Moore formulated the law that came to be named after him, which states that the complexity of integrated circuits doubles every one to two...

Im Focus: Researchers demonstrate size quantization of Dirac fermions in graphene

Characterization of high-quality material reveals important details relevant to next generation nanoelectronic devices

Quantum mechanics is the field of physics governing the behavior of things on atomic scales, where things work very differently from our everyday world.

Im Focus: Graphene: A quantum of current

When current comes in discrete packages: Viennese scientists unravel the quantum properties of the carbon material graphene

In 2010 the Nobel Prize in physics was awarded for the discovery of the exceptional material graphene, which consists of a single layer of carbon atoms...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Networking 4.0: International Laser Technology Congress AKL’16 Shows New Ways of Cooperations

24.05.2016 | Event News

Challenges of rural labor markets

20.05.2016 | Event News

International expert meeting “Health Business Connect” in France

19.05.2016 | Event News

 
Latest News

11 million Euros for research into magnetic field sensors for medical diagnostics

27.05.2016 | Awards Funding

Fungi – a promising source of chemical diversity

27.05.2016 | Life Sciences

New Model of T Cell Activation

27.05.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>