Technologists at the India's Council of Scientific and Industrial Research and the National Physical Laboratory in New Delhi claim to have found a way of providing an early warning on earthquakes and are currently engaged in filing patent applications for the system.

According to NewScientist journal, the team is using an acoustic meteorological technique called Sonic Detection and Ranging (Sodar), to measure wind speeds by firing sound pulses through the air and checking for Doppler frequency shifts.

The system uses a parabolic dish to fire sonic pulses at 50 millisecond intervals vertically into the sky, 24 hours a day, while recording the faint reflections that come back down from the atmosphere. If there are any infrasonic sound waves around these will imprint on the reflections.

The researchers claim their system can give a warning several hours before any quake larger than 5 on the Richter scale and within 250 km of the dish. However, testing of the system can only be done when another large quake strikes.