Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Getting ready for the ’big one,’ researchers make most detailed survey ever of San Adreas Fault

09.12.2005


Images show never-before-seen fault lines – plus cows, trees




Researchers have completed the most meticulous survey ever made of the San Andreas Fault, and they’ve found detailed features that nobody could have seen before.

Michael Bevis, Ohio Eminent Scholar in geodynamics and professor of civil and environmental engineering and geodetic science at Ohio State University, unveiled the first images from the ambitious new survey Wednesday at the American Geophysical Union meeting in San Francisco.


His team will spend the next year processing the rest of the survey data, which they gathered using ultra-high-resolution global positioning system (GPS) technology and a radar-like system called lidar.

Short for "light detection and ranging," lidar measures the time it takes for light to reflect off the surface of an object. The combined GPS and lidar technologies enabled the researchers to map the surface of the San Andreas Fault with 5-centimeter (1.97 inches) vertical resolution.

The researchers dubbed their survey the "B4" Project, because the data will form the "before" images that scientists will compare to "after" images of the next big San Andreas earthquake when it inevitably happens.

Scientists know more or less what happens away from a fault line during an earthquake, Bevis said. But what happens near or in the fault, or how an earthquake starts – these things are not well known, and are frequently debated among scientists.

"By having this high resolution image of before and after a quake, we should be able to resolve some of these debates," Bevis said.

They loaded their equipment on board a twin-engine Cessna airplane, and covered nearly 1,000 kilometers (621.37 miles) of the fault in two months of flights, during May and August of 2005.

Bevis recalled that the flights required near-heroic effort from the team pilots. "We had to fly low and closely manage the orientation of the aircraft at all times so we knew exactly where the laser on the lidar instrument was pointing," he said.

A less-controlled airborne photographic survey would have been easier, but also much more time consuming. "To do this kind of survey the traditional way would take years – just to process the photographs. We’ll have preliminary results in a month, and refined results in six months," Bevis said.

The San Andreas fault splits in the south, with one of the two offshoots becoming the San Jacinto Fault. The B4 Survey covered both, tracing the main fault lines and countless smaller lines branching from them.

Looking at one of the images, Bevis easily picked out the SUV belonging to team members who drove along the fault ahead of the plane. Even the tripod holding one of their portable GPS stations was visible. He identified other dots on the image as cows and small trees.

How could he tell which ones were cows? "When we looked back later, some of them had moved," he said.

The team will post its maps on the Web. "As we do each day’s processing, we’ll make it available to the whole scientific community," Bevis said. "People are going to find all kinds of faults and other features that they never knew about before.

"Often a fault line is fairly subtle," he continued. "There are some spots where, if you were actually standing on the ground, and you weren’t a geologist who knows the area really well, you probably couldn’t even see it. But in these images you can."

Scientists anticipate that a "Big One" – an earthquake of magnitude 8 or more on the Richter scale – will eventually strike California via the San Andreas. The 1906 San Francisco Earthquake was blamed on the fault, and scientists believe it would have registered near magnitude 8, had the scale existed then. But when another Big One will strike is an open question.

As detailed as the new survey is, Bevis said it can’t be used to predict the future.

"The point of the B4 Project is to learn more about earthquakes in general," he said. "People think we may one day find a way to predict earthquakes, but I think it may be impossible. Not all processes are predictable."

Michael Bevis | EurekAlert!
Further information:
http://www.osu.edu

More articles from Earth Sciences:

nachricht Global study of world's beaches shows threat to protected areas
19.07.2018 | NASA/Goddard Space Flight Center

nachricht NSF-supported researchers to present new results on hurricanes and other extreme events
19.07.2018 | National Science Foundation

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>