When last Apriltwo major earthquakes shook the Indian Oceanand the Indonesian island of Sumatra, a tectonic gap was set in motion within the Indo-Australian plate. Two investigations published in the journalNaturereveal thatthe earthquakes were 40% more intense than previously thought and their consequences are analyzed.
As Matthias Delescluse, co-author of one of the studies, explained to the SINC agency,the earthquake that occurred in the same area in 2004 produced a deformationand “added a little more tension to the area, and this caused the earthquake of 2012 in the medium term, like a drop overflowing a glass full of water.” Delescluse further points out that, in the movement of the Indo-Australian plate, “Australia moves north, while India resists this movement due to the collision with the Himalayas, causing a fracture in the interior of the plate.”
In the second work, a team led by the seismologist Thorne Lay analyzes the Sumatra earthquake in detail and reveals that the earthquake caused the rupture of at least four faults in 160 seconds, and that the phenomenon is part of the separation process of the Indo-Australian plate on two separate plates. The main earthquake originated inside the plate, unlike those that occurred in the area in 2004, 2005 and 2007, which occurred by subduction – one plate is introduced below the other – at the tectonic limits. According to Lay,?2012 is the largest earthquake to occur inside a tectonic platerecorded by our instruments ?. The researcher concludes that the earthquake activated the fault system and this would be the early phase of the fracture. “It will take tens of millions of years until the limit is defined,” he warns.
The magazine also publishes a third study, directed by Fred Pollitz, which analyzes the global impact of that earthquake. The work shows that, in the six days after April 11, the number of earthquakes of more than 5.5 degrees that occurred more than 1,500 kilometers away from that of Sumatra multiplied by five. According to Pollitz to SINC, “no other earthquake has triggered so many large aftershocks around the worldlike this”.
