In spite of the temblor 's substantial size, the slippage along the fault stopped propagating well before it reached the earth's surface.
Even the global sea level is now half a millimeter higher than it was before the temblor .
The first temblor on Saturday, measuring 5.5 on the Richter scale, hit shortly after midnight, followed by a second measuring 6.2 about seven hours later.
The temblor , which injured almost 600 people, hit the northernmost island of Hokkaido hardest, but swayed buildings as far away as Tokyo, about 830 km to the southeast.
Even a distant temblor could cause a levee break, inundating heavily populated low-lying residential areas- and more homes are being built in flood-prone areas each year.
In the 70 years prior to the 1906 earthquake, a temblor of at least magnitude 6 struck the region an average of every four years, she said.
The temblor proved that an earthquake smaller in magnitude can cause greater damage than a more powerful earthquake.
Earthquakes of 9.0 are exceedingly rare and occur only along subduction zones where an intense force builds, perhaps over hundreds of years, until the plate gives way and a violent temblor results.
The temblor also damaged hundreds of houses and buildings, including the local legislative council building and several churches and mosques, and five bridges.
There have been over 500 aftershocks since the temblor , causing interruptions in the rescue effort.