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 Climate satellite: Tracking methane with robust laser technology
22.06.2017 | Fraunhofer-Gesellschaft

nachricht How reliable are shells as climate archives?
21.06.2017 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Study shines light on brain cells that coordinate movement

26.06.2017 | Life Sciences

Smooth propagation of spin waves using gold

26.06.2017 | Physics and Astronomy

Switchable DNA mini-machines store information

26.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>