A recent study found that Japan shifted eastward by about 5 to 6 millimeters after a massive 9.0 magnitude earthquake in 2011. The movement was caused by a seismic wave that traveled down to Earth’s core and then rebounded to the crust, displacing four major tectonic plates.

Seismic Event

The wave was triggered by the earthquake and caused a uniform movement across the entire country. This phenomenon is considered extraordinary and previously undocumented. The movement did not match the timing of the initial earthquake and occurred before any significant aftershocks.

According to University of Chicago geophysicist Sunyoung Park, who led the research, the movement is noteworthy because it occurred over such a large area, making it the broadest ever recorded. The displacement released about the same amount of energy as a 7.5 magnitude earthquake.

The 2011 earthquake, which struck 231 miles northeast of Tokyo, was the worst to ever hit Japan, triggering a huge tsunami and a nuclear crisis and killing an estimated 20,000 people. Park said policymakers should be aware of this previously unknown source of seismic hazard.

The round-trip journey to Earth’s core and back takes about 15 minutes, making it a seismic event that could be anticipated and potentially prepared for. However, because the energy of the seismic event was distributed over an extremely broad area, it would have been felt less strongly and caused less damage than a typical magnitude 7.5 earthquake.

Original reporting: KTVZ (Central Oregon) — read the source article.