The same technology that pesters you with targeted advertisements on the internet was adapted to help seismologists locate the planet’s earthquake hotspots. Data mining software was used to analyze data from 1,500 earthquakes.
"The method was originally developed for analyzing online user data," said Thomas Landgrebe, of the University of Sydney in Australia, in a press release. "The technique we apply is commonly used to find a few specific items which are expected to be most appealing to an Internet user. Instead, we use it to find which tectonic environment is most suitable for generating great earthquakes."
"We find that 87 percent of the 15 largest (8.6 magnitude or higher) and half of the 50 largest (8.4 magnitude or higher) earthquakes of the past century are associated with intersection regions between oceanic fracture zones and subduction zones," said Dietmar Müller of University of Sydney in Australia and lead author of the Solid Earth paper, in a press release.
The technique was particularly effective for intense quakes like the 2011 Japanese Tohoku-Oki quake and 2004 Sumatra event that lead to the Indian Ocean tsunami. Both of those temblors occurred at the intersections of oceanic fracture zones and subduction zones.
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Most quake records go back only a few centuries, but some zones experience massive quakes on a millennial scale. By using data mining software to analyze historical records and geological clues seismologists can overcome the difficulty of identifying quakes that have long intervals between events. For example the Tohoku-Oki region hadn’t had a major quake in the last century, but was on one of the intersection zones the study identified as a risky area.
"The power of our new method is that it does pick up many of these
regions and, hence, could contribute to much-needed improvements of
long-term seismic hazard maps,” Müller said. “Even though we don’t fully understand the physics of long
earthquake cycles, any improvements that can be made using statistical
data analysis should be considered as they can help reduce earthquake
damage and loss of life.”
Map showing subduction zones and oceanic fracture zones. The blue bands are subduction interfaces – the parts of the subduction zone where the subducting plates are physically 'grinding’ against the overriding plates. Colored in red are the areas where oceanic fracture zones intersect these interfaces, which have higher probability of generating great earthquakes. (Credit: Müller and Landgrebe)