India has witnessed 127 miniature earthquakes in the first half of 2020. From the far east of Arunachal Pradesh to the far north of Kashmir Valley, the south to national capital Delhi itself, minute tremors have become a daily affair. A similar trend has been seen across the world. But do they mean that a big one is one it's way? Here is what experts at the United States Geological Survey have to say.
The question put to the USGS was -- Why are we having so many earthquakes? Has naturally occurring earthquake activity been increasing? Does this mean a big one is going to hit? OR We haven't had any earthquakes in a long time; does this mean that the pressure is building up for a big one?
To this, the USGS replied, "A temporary increase or decrease in seismicity is part of the normal fluctuation of earthquake rates. Neither an increase or decrease worldwide is a positive indication that a large earthquake is imminent."
It further added, "The ComCat earthquake catalog contains an increasing number of earthquakes in recent years not because there are more earthquakes, but because there are more seismic instruments and they are able to record more earthquakes. The National Earthquake Information Center now locates about 20,000 earthquakes each year, or approximately 55 per day. As a result of the improvements in communications and the increased interest in natural disasters, the public now learns about earthquakes more quickly than ever before."
"According to long-term records (since about 1900), we expect about 16 major earthquakes in any given year, which includes 15 earthquakes in the magnitude 7 range and one earthquake magnitude 8.0 or greater. In the past 44 years, from 1973 through 2017, our records show that we have exceeded the long-term average number of major earthquakes only 11 times, in 1976, 1990, 1995, 1999, 2007, 2009, 2010, 2011, 2013, 2015, and 2016."
The year with the largest total was 2010, with 24 earthquakes greater than or equal to magnitude 7.0. In other years the total was well below the 16 per year expected based on the long-term average: 1989 only saw 6, while 1988 saw only 7 major earthquakes.