Minutes after the devastating earthquake and tsunami that struck Japan in 2011 and led to his death Nearly 20,000 peopleA new study has revealed that a “previously unrecognized” phenomenon may have caused the entire country to shift eastward.
This is amazing Huge earthquakes They are often followed by events that cause additional ground motion, which is associated with aftershocks.
But exactly all the different ways that Aftershocks Scientists say that this phenomenon is not entirely clear.
In a new study, researchers evaluated satellite data to study the magnitude 9 Tohoku-oki earthquake and its seismic effects.
The researchers found that the devastating earthquake led to the sudden sliding of blocks of rock next to each other along the fault line.
This also led to seismic waves traveling through the Earth, bouncing off the planet’s core, and then returning to the surface to reactivate the boundaries of the tectonic plates in the region.
These were “shear waves” that traveled through the Earth’s interior and caused rock particles to vibrate in a “shearing” or side-to-side motion.
A pedestrian road collapsed in the devastating 8.9 magnitude earthquake (AFP via Getty Images)
The latest findings reveal a previously unknown hazard that could activate or reactivate the main area of the earthquake, according to the study published in the journal. sciences.
“We report an unusual observation of ground motion in Japan after the 2011 magnitude 9 Tohoku-oki earthquake, which was attributed to a multi-plate slip event caused by a shear wave that traveled to the Earth’s core and back,” the researchers wrote in the study.
In the study, scientists re-examined satellite data to look for hidden movements in the minutes surrounding the 2011 earthquake.
They found that seismic waves traveling through the Earth and bouncing off the Earth’s core moved all of Japan by as much as 5-6 mm.
While this may not be much and is a common amount of ground movement after large earthquakes, what surprised scientists was how much ground actually moved.
The resulting slide “contains the widest rupture zone of any single event documented to date,” the researchers wrote.
“Its total length is similar to the length of mainland Japan (about 3,000 km), exceeds the mainshock rupture length by 6 to 7 times and is more than twice the length of the 2004 Great Sumatra Earthquake,” they wrote in the study.
The researchers say that this ground movement spread over several minutes, and people may not have felt it happening under their feet.
However, researchers say this new type of seismic hazard needs further study.
“I think we have to be aware of the fact that there could be this potential event several minutes later [an earthquake’s] “The major shaking has passed,” said study author Sunyoung Park. American Scientific.
