Japan’s Previous Largest Earthquake

In the aftermath of the tremendously huge Earthquake that hit Japan, many are trying to put their lives back together in a world that seems increasingly unpredictable.  And yet Japan is, as many have stated, a country that has had to deal with Earthquakes in the past.  But what was the previously largest Earthquake to hit Japan?  And why was this one so much bigger?  Perhaps by studying the history of the country we can gain some perspective on this profound tragedy.

October 28, 1707 started as uneventfully as so many others.  And yet when the clock finally rolled around to 2:00 PM local time, the ground began to inexplicably shake.  Being no stranger to Earthquakes, the people of Hoei, where the event took place found themselves unprepared for the sheer level of devastation that gripped their city.  Tearing through Honshu, it made its way to Shikoku and Kyushu before finally ceasing.  The entire event, though powerful only lasted a period of eleven seconds.

And the event itself was fairly mysterious.  It somehow cut a line directly through all of the Nankai megathrust, splitting all of the segments simultaneously.  Of course this would not become known until over a hundred years later as scientists studied the profound effects the event had on the changing landscape.  As scientists uncovered the devastation years later they would be humbled by just how powerful the event was.  It was so devastating that Mount Fuji would erupt 49 days later.

Survivors throughout Hoei found themselves amidst devastation that had previously never been recorded by a seismic event.  As they scrambled to put the pieces back together they found themselves having to reconstruct much of their society which had been lost.  And yet they found themselves in quite different conditions than the most recent Earthquake.

One of the points of interest with the latest quake is that it took place as the moon approached what is being called a “Super” phase.  This phase will see the moon not only at an incredibly close proximity to Earth, but will also be full at the time.  During the event in 1707 the moon was a new moon and was undergoing a partial (Umbral) eclipse only two days prior.

Furthermore, the vast infrastructure and dangerous facilities did not exist in that time.  The latest disaster took place near a nuclear facility and as the Earthquake devastated the city the cooling system was damaged.  Of course these facilities did not exist in 1707.  And there is much speculation that the previously largest Earthquake saw quite a different amount of financial devastation as well.  Of course just how different will remain unknown until the final total cost is discovered on the latest event.

Perhaps by studying the past event we can gain some perspective on the new Earthquake and learn how the two are linked and how they differ.