Surface ruptures of the 1891 Nobi earthquake

At the XIX INQUA congress in Japan I had the chance to see the surface ruptures of the 1891 Nobi earthquake during the mid-congress excursion M-2. This quake caused huge damage, but more interestingly for me, it produced amazing surface ruptures which are preserved even more than a hundred years after the event. The M7.5-M8 quake occurred in a mountainous area and was mainly strike-slip (more than 8 m!), but significant vertical uplift was found at step-overs. In 1991, the wonderful Neodani Fault Museum opened to the public, its main attraction being a paleoseismological trench exhibiting more than 5 m of vertical offset! Simply astonishing. Thanks to Atsumasa Okada, Heitaro Kaneda and Keitaro for this great excursion!

An interesting article on this quake was published in 1893 by Bundjiro Koto, in which he states the following:

The sudden elevations, depressions, or lateral shiftings of large tracts of country which take place at the time of destructive earthquakes are usually considered as the effects rather than the cause of subterranean commotions; but in my opinion, in can be confidently asserted that the sudden formation of the ‘great fault of Neo’ was the actual cause of the great earthquake of the 28th of October, 1891 […].

This can certainly be considered a milestone in modern earthquake research.

The site where the famous historical picture was taken few days after the earthquake
The site where the famous historical picture was taken few days after the earthquake
Me in front of the surface rupture
Me in front of the surface rupture
5 m vertical offset, Franck Audemard for scale
5 m vertical offset, Franck Audemard for scale
Neodani Fault Museum
Neodani Fault Museum
Neodani Fault Museum
Neodani Fault Museum
The earthquake kit - every family here has one. Neodani Fault Museum
The earthquake kit – every family here has one. Neodani Fault Museum
Major quakes in Japan, Neodani Fault Museum
Major quakes in Japan, Neodani Fault Museum
Where's my fault? Neodani Fault Museum
Where’s my fault? Neodani Fault Museum

Geologists staring at things
Geologists staring at things
Magnitude 8 restaurant
The M8 bar
Left-lateral offset rice paddies
Left-lateral offset rice paddies
Left-lateral offset tree line
Left-lateral offset tree line
Left-lateral offset tea hedge
Left-lateral offset tea hedge
Left-lateral offset tea plant hedge
Left-lateral offset tea plant hedge
Explaining trenching results in the field
Explaining trenching results in the field
M-2 group photo
M-2 group photo

Further reading

KML of the field trip stops

 

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