Throughout Japan there are literally tens of thousands of points, many of them measured and charted as long as 100 years ago, that are used in surveying, charting, making and maintaining all maps. There has been a massive shift of these points and intersections throughout the country, to a degree seen only once before in Japan’s history.
Japan’s central measuring point from which all other measuring points radiate is located in a quaint, small Greco-Roman stone building in a public park in Tokyo. It sank an unprecedented 2.4 centimeters (1 inch). In Tokyo, the Azabu ward and much of the Chiyoda ward has shifted.
The massiveness of the affect can be judged by the announcement from the Geospatial Authority of Japan. It was made after the government enacted a new Land Survey Act to revise Japan’s leveling and geodetic datum: 109,000 trigonometric points and 18,000 level points for surveying throughout Japan will now change as a result of the extensive geodetic shift that has taken place.