A research team from the University of Texas and the Royal Geographic Survey examined data on earthquakes that have happened over the last 30 years. In all, they studied 205 big earth quakes with a magnitude of 7 or higher, and 25,222 moderate quakes with a magnitude between 5 and 7. They studied these quakes because earthquakes of this size can be picked up with instruments anywhere in the world.

Their evidence found that there is an increase in moderate quakes in the 24 hours after a larger quake, but they all take place within 600 miles of the large quake, and most of them happen within 375 miles. Therefore, there is an increased regional danger after a large earthquake, but the global hazard does not increase.

This evidence comes in good timing, since a lot of people have been suspecting that the Christchurch earthquake and the following one in Japan were connected. “A big quake rings the earth like a bell and can trigger little quakes” in the surrounding region, said Dr. Tom Parsons of the United States Geological Survey in Menlo Park, CA.

“But apparently it doesn’t trigger other big quakes” in different regions of the world, he said. Dr. Parsons said the first clue of this came in 1992 when a 7.3 earthquake hit Landers, California and the whole western part of the United States had earthquakes for the next few days.