A new study revealed that earthquakes can significantly alter the elastic properties of the Earth's crust.
Researchers from the Massachusetts Institute of Technology Department of Earth explained that earthquakes which are triggered by other earthquakes indicate deeper changes that are happening beneath the surface of the planet.
In a study issued in the journal Science Advances, Andrew Delorey and his colleagues found that the the ability of the Earth's crust to withstand stress for a period of time is affected by seismic waves from distant earthquakes, enabling widespread perturbations in the crust and in faults. The change can even affect regions which are 6,000 kilometers or 3,700 miles away from the earthquake.
Kevin Chao, a member of the research team, explained that the Earth's terrestrial structures are an interconnected and dynamic system, and that one quake can lead to a cascading chain of events.
Researchers say that stress builds up on a tectonic fault and causes it to slide or move and release seismic waves. These waves can either be body waves which cause the extremely damaging shaking movement, or surface waves which travels underneath the ground.
"When surface waves pass through, all of these properties rearrange and change," said Chao. "If a fault with high stress is ready to fail, it will accumulate more stresses in the fault, meaning an earthquake could occur at any time."
The study focused on examining the 8.6-magnitude earthquake that occurred in North Sumatra in 2012. The earthquake was reported to have been followed by two more earthquakes in Japan.
Researchers found that the following earthquakes which had magnitudes greater than 5.5 were part of a cluster of activity in the Indian Ocean days after the earthquake occurred.
Chao explained that when the Indian Ocean earthquake happened, surface waves passed through the northeastern region of Japan and triggered seismicity in the area.
The event was an additional stressor to the already critically stressed area of the Earth's crust, especially after Japan was hit by an earthquake in 2011.
Meanwhile, scientists say that they still cannot predict if there will be another earthquake after the first one has struck. They said that despite being aware of the changes that are happening beneath the surface, they still have no knowledge of existing stress conditions in every region.
The most important thing, scientists believe, is that they have acquired a different understanding on how earthquakes interact with one another.
