1. There are several million earthquakes annually
According to the United States Geological Survey, there are around 17 major earthquakes measuring above 7.0 on the Richter scale – and one great earthquake measuring above 8.0 – each year. However, experts estimate that there are actually several million earthquakes annually; many go undetected due to their geographical remoteness or small magnitude.
2. An earthquake can affect the length of a day
On 11 March 2009, an 8.9 magnitude earthquake which struck northeast Japan altered the distribution of the earth’s mass, causing it to rotate slightly faster, and shortening an earth day by around 1.8 microseconds.












