The United States Geological Survey (USGS) linked 114 remote earthquakes to the magnitude 8.6 East Indian Ocean quake that occurred April 11, 2012.
USGS seismologist Fred Pollitz and colleagues published their findings Sept. 26, 2012 in "Nature."
The study focused on global seismic activity triggered by the East Indian Ocean quake, according to a USGS press release.
The scientists found that the magnitude 8.6 earthquake triggered 114 earthquakes that were a magnitude 4.5 or greater in the six days following the quake.
As a result of the findings, the team is redefining the definition of an aftershock. Currently, the term aftershock refers to earthquakes that happen after and nearby the main fault rupture. The new definition will consider aftershocks to be earthquakes of any size and location that would not have taken place had the main shock not struck.
The difference in the two definitions is that an earthquake thousands of miles away can now be called an aftershock of the first earthquake if the seismic activity of the first quake can be determined to have caused the later quake.
After studying the seismic activity after the East Indian Ocean quake, the scientists determined that large earthquakes as far away as Mexico and Japan, in the following days, were actually aftershocks.
The East Indian Ocean was the largest, by a factor of 10, strike-slip earthquake ever recorded. A strike-slip earthquake is caused by two sections of tectonic plates sliding along each other horizontally with very little vertical movement.
"No other recorded earthquake triggered as many large earthquakes elsewhere around the world as this one," said Pollitz.
Remote earthquakes in the six days preceding (top) and the six days following (bottom) the M=8.6 main shock in the East Indian Ocean on April 11, 2012. The color scale indicates seismic stress, with purple = zero and red = high. This graphic is courtesy of USGS.gov.
Tropical Depression 8 should strengthen into a tropical storm before impacting the coastal Carolinas with rough surf and heavy downpours early this week.
Tropical Depression 9 developed just south of Florida on Sunday and will turn toward the northeastern Gulf Coast of the United States this week.
Brief relief from heat and humidity will arrive in the northeastern United States at the start of September.
Typhoon Lionrock is poised to make landfall in Japan near Sendai early this week with heavy rainfall, damaging winds and an inundating storm surge.
Two tropical systems, Madeline and Lester, could pose hazards to Hawaii from the middle of the week into Labor Day weekend.
Hot and dry weather will greet fans and competitors at the 2016 U.S. Open Tennis Championships in Flushing, New York, as play begins Monday, Aug. 29.
New England (1816)
"Year in which there was no summer", otherwise known to weather historians as "1800 and frozen to death" killing frost once again damages sparse corn corp in northern New England...loss of this and other crops led to severe famine in much of New England that winter...and helped spur western migration in spring of 1817.
New England (1965)
A total of 2.5 inches of snow on top of Mt. Washington set an August record. Vermont had a reading of only 25 degrees, while Nantucket had a chilly 39 degrees. Earliest freeze on record at many stations.
Houston, TX (1980)
2.23 inches of rain fell in less than 1 hour. Streets were flooded in the downtown district and a tornado touched down briefly west of Houston at Sealy, TX.