This Seismologist is a Fearmonger.
He fails to clarify that a movement of 20 Meters will
take 217.3913 years to develop.
The Pacific Plate subducts under the Okhotsk Plate where
Japan rests at a rate of 92MM per year.
20,000MM/92 = 217.3913 Years.
If the plates had any small earthquakes during this period,
the Developing Period would be longer.
Another Japanese Seismologist stated that the 2011
earthquake was a Millenial Event.
Japan can expect more M8 - M9 Earthquakes in the Future.
I doubt that a M10 will ever occur anywhere since most
subduction zones have Frequent Smaller Quakes.
Herman dislikes Fear Mongers.