6.9 7.9 or 8.1?

The debate continues. The Indian Meteorological Department (IMD) puts the magnitude at 6.9 on the Richter scale, and France, China and the US measure it at 7.9, later upgraded to 8.1. The National Geophysical Research Institute (NGRI) and the Bhabha Atomic Research Centre (BARC) endorse the US assessment. The US used the readings of around 200 observatory stations, while the IMD based its calculation from three of the country's 57 observation centres. According to the IMD, the difference is due to the different method of measurement: it uses the body waves while the US uses shock waves. According to seismologists, the shock wave calculation is appropriate as it gives the real picture. The two most popular scale of quake measurement are the Richter scale and the upgraded Mercali scale. The first one measures the energy released in an earthquake while the second gives the impact of the earthquake like damages. Russia and China have their own scale of measurement.