the earthquake in Japan on March, 11, moved the Earth on its axis by about 4 to 6 inches, which resulted in shortening of a day by around 1.8 microseconds.
Massive earthquakes typically affect the Earth’s rotation with the impact of every individual earthquake depending on its magnitude, location, and the details of how the fault slipped. The 8.9/9.0 magnitude earthquake which hit the Pacific Ocean near Northeastern Japan at around 2:46 pm on March, 11 caused extreme damage and unleashed a devastating tsunami a day after, when waves crashed 10 kilometers inland.
This was the largest earthquake ever recorded in Japan and the subsequent tsunami traveled across the Pacific Ocean, reaching as far as the western coasts of Canada, the U.S. and Chile. In addition to this, during the first 24 hours, the initial earthquake triggered more than 160 aftershocks.