Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

ESA satellite imagery credited with breakthrough in earthquake research

19.09.2002


California scientists credit synthetic aperture radar imagery from the European Space Agency with making possible new ways to depict earthquake fault zones and uncovering unusual earthquake-related deformations. Their study of imagery from a 1999 earthquake in the western US could provide a new way to identify active faults and help track when the last earthquake occurred on a fault zone.



Writing in last week’s issue of Science magazine, researchers from the Scripps Institution of Oceanography at the University of California in San Diego, and the California Institute of Technology detailed their studies of the so-called “Hector Mine” earthquake, a magnitude 7.1 earthquake that tore through 28 miles of faults in the Mojave Desert. Named after a nearby abandoned mine in the remote area, the earthquake caused virtually no damage. It was, however, the “perfect” event to use satellite and radar technologies to document unique characteristics of faults, said Scripps’ Yuri Fialko, the study’s lead author.
The earthquake was comprehensively imaged with interferometric synthetic aperture radar (InSAR), which uses a series of satellite recordings to detect changes in the Earth’s surface. The most surprising finding that came out of the analysis of the imagery was the first evidence that faults can move backwards.
“Even small stress perturbations from distant earthquakes can cause faults to move a little bit, but it’s only been known to cause this motion in a forward sense,” Fialko said in a Scripps announcement of the study’s publication in Science. “Here we observed the faults coming backwards, due to relatively small stress changes, which is really quite unusual.”


The article argues that the backward motion on the faults is caused by the dissimilar nature of material within the faults, rather than frictional failure. The results, Failko said, will guide new seismic studies to areas with contrasting fault materials and can then be used to identify potentially active faults.

Co-author Peter Shearer of Scripps credited the study’s detailed results to the “breakthrough” offered by InSAR technology.

“Prior to InSAR, all we had were spot measurements of the deformation field,” the Scripps scientist said. “With InSAR we have millions of points and thus a continuous picture of the deformation across southern California.”

Using the satellite data, the study was able to document both vertical and horizontal terrain displacements of several millimetres to several centimetres across kilometre-wide zones centred on faults.

“The findings became possible due to highly successful satellite missions of the European Space Agency,” the scientists were cited as saying by the Scripps announcement.

In the Science article, the authors pointed out that the earthquake area had been imaged repeatedly by ESA’s ERS-1 and ERS-2 satellites over the past 10 years. The research team generated and analysed all possible interferometric pairs that included the earthquake date, ending up with 15 interferograms from a descending orbit, and five interferograms from an ascending orbit.

The first synthetic aperture radar was launched in 1991 as one of three main instruments on ESA’s ERS-1 satellite. It was followed by a second on ERS-2 in 1995. These highly successful ESA satellites have collected a wealth of valuable data on the Earth’s land surfaces, oceans, and polar caps. Today, several hundred research groups worldwide use ERS data to further their studies. With ERS data, the InSAR technique represents a major breakthrough in Earth sciences, allowing scientists to understand better earthquakes and other natural events.

Europe’s latest environmental satellite, Envisat, was launched earlier this year carrying an advanced SAR (ASAR). Envisat’s ASAR instrument is the first permanent spaceborne radar to incorporate dual-polarisation capabilities - the instrument can transmit and receive signals in either horizontal or vertical polarisation. This dramatically improves the capability of SAR to discriminate between different types of terrain compared with the sensors on the earlier ERS generation of satellites, while offering a continuity of service to users working with the InSAR technique.

Henri Laur | alfa
Further information:
http://www.esa.int

More articles from Earth Sciences:

nachricht NASA's AIM observes early noctilucent ice clouds over Antarctica
05.12.2016 | NASA/Goddard Space Flight Center

nachricht GPM sees deadly tornadic storms moving through US Southeast
01.12.2016 | NASA/Goddard Space Flight Center

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

IHP presents the fastest silicon-based transistor in the world

05.12.2016 | Power and Electrical Engineering

InLight study: insights into chemical processes using light

05.12.2016 | Materials Sciences

High-precision magnetic field sensing

05.12.2016 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>