A joint Chinese-European team is using satellite radar data to monitor ground deformation across major continental faults in China.
The scientists - who are part the European Space Agency's Dragon 2 program - are combining synthetic aperture radar satellite data and SAR interferometry (inSAR) with GPS data to measure the ground deformation that occurred during the Wenchuan earthquake that struck China's Sichuan province in May 2008.
‘If an area is moving slowly after a quake, we know it is not accumulating energy and we believe it is safe,' said Shen Zhengkang of the Institute of Geology, China Earthquake Administration. ‘However, if an area on the fault is not slipping, but there is movement around it, then this is a bad sign. We will have to watch this area more carefully.'
The Wenchuan earthquake occurred on the Longmen Shan fault, along the eastern margin of the Tibetan Plateau. Major earthquakes cause changes in stress along the faults in the region. These changes can lead to more earthquakes. Using InSAR and GPS data, scientists can measure stress changes and how associated deformation is distributed.
According to Shen, the team has found that some regions on the fault did not rupture much during the earthquake. The question the scientists are now asking is whether this means the energy is still partially locked and therefore, accumulating for the next earthquake. Another possibility is that these regions had accumulated less energy prior to the quake than scientists originally thought.
The team working on this project includes Sun Jianbao of the Institute of Geology, China Earthquake Administration, Shen Zhengkang of IGCEA and Peking University and Cecile Lasserre from France's Laboratoire de Geophysique Interne et Tectonophysique.
Source: www.asmmag.com
