Surat, India: GPS users often complain about some inaccuracy in the device. A researcher at the Sardar Vallabhbhai National Institute of Technology (SVNIT), Surat, India, turned that inaccuracy into a tool to predict earthquakes.
The researcher, Sheetal Karia, supported her findings by studying the data from three earthquakes in different parts of the world in the last three years. As part of her study, Karia developed a model to predict an earthquake. Papers written by her on the quake prediction model have been published by internationally acclaimed journals. The model has not predicted any quake but post quake studies in three earthquakes supported the findings.
The study established that underground tectonic plate activities that lead to a quake create an electromagnetic field. The field also affects the atmosphere overground which is scaled through variation in GPS data. It studies TEC variations obtained using GPS measurements and electron density observations by the detection of electro-magnetic emissions transmitted from earthquake regions.
In an interview to an Indian daily, Karia explained, “Many a time, GPS data waves from satellite have variation due to which it gives inaccurate positioning. The variation is because of electro magnetic activity in ionosphere that creates disturbance in path of the GPS data. And in specific cases the electro magnetic activity is because of tectonic plate movement”.
Describing further, Karia said, “Ionosphere is a layer in atmosphere between 80 km from ground to 350 km. Study of this layer gives important information related to GPS signals. Studying data prior to Bhuj quake of October 29, 2009 we could find out variation around three days prior to the quake. Similarly, the Sumatra quake of September 30 in same year could have been predicted five days prior.”
It is a very complex but important study in which the inaccuracy has been turned into knowledge. While studying Bhuj quake data Karia could access the GPS data through a receiver at SVNIT while she examined Sumatra quake in association with Shivalika Sarkar, a researcher from Barkatullah University, Bhopal. For the Sumatra quake study, GPS data from DEMETER satellite of Russia was used.
Source: Times of India