Road damage following an earthquake
[NEW DELHI] India and France are to carry out a joint project that they hope might eventually allow satellites to predict earthquakes from space.
The research is based on anecdotal reports that the earth's crust emits characteristic electromagnetic (EM) radiation a few hours before an earthquake. This radiation, it is said, perturbs the upper part of the Earth's atmosphere by causing, for example, a sudden drop in electron density.
The Indo-French project aims to use satellite and ground-based instruments to study fluctuations in the ionosphere — the Earth's upper atmosphere — before, during and after earthquakes in the seismically active ‘Himalayan arc’ region. Researchers will then use these data to try to develop a model for forecasting earthquakes.
Although a great deal is known about where earthquakes are likely to occur, there is currently no reliable way to predict when an event will occur in any specific location.
If the study confirms that EM radiation can be used to predict earthquakes (a theory that remains highly contested in the scientific community), the study could have significant implications for seismically active countries such as India, which saw severe devastation and 15,000 deaths in last year's earthquake in the state of Gujarat.
"The proposed project aims at unambiguously identifying the seismic signatures in the ionosphere by combined measurements from space and the ground and correlating the data with seismic events," says Ashok Kumar Gwal from the Barkathulla University in Bhopal, who will lead the Indian research.
The New Delhi based Indo-French Center for Promotion of Scientific Research — a body set up by the governments of both countries 15 years ago — has approved the three-year Rs.7 million (US$144,000) project, according to P.G.S. Mony, director of the Center.
The project would use a French micro-satellite known as DEMETER — which stands for Detection of Electromagnetic Emissions Transmitted from Earthquake Regions — to "search for the ionospheric precursors of earthquakes over high seismic regions across the
entire globe," says Michel Parrot of the French scientific agency CNRS in Orleans, who is leading the French side of the project.
DEMETER will measure electromagnetic waves of frequency up to 4 MHz, and plasma parameters such as the local electron density and temperature at the altitude of the satellite.
Parrot says that France decided to build and launch DEMETER as a prototype satellite for earthquake prediction following encouraging results that his team obtained from EM sensors on scientific satellites. Analysis of data from these sensors showed spikes of EM radiation when there was a strong earthquake on the ground.
"We have examined the records of more than 1,000 seismic events from 48 different ground stations occurring during the last 27 years and found a correlation between strong seismic events and ionosphere perturbations recorded by the satellite sensors," he says.
Gwal said the project will enable simultaneous recording of the ionosphere by the French satellite as it flies over areas of high seismic activity in India. In addition, a network of 12 ground stations, which are being set up by the Indian Space Research Organisation, will study the ionosphere over India under a project called Coherent Radio Beacon Experiment or CRABEX.
© SciDev.Net 2002
Photo credit: NASA