Earthquakes: The Scare The Pants Off You Edition


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I noticed this post by Rich over at GPS Tracklog this morning and couldn’t help by point it out to everyone. As commented on by Rich there is onviously a lot of trauma and distress in Japan (and Christchurch) at the moment but this is one of those reports that gives an indication of just how powerful the Japanese earthquake was:

GPS stations point to Japan being moved 8 feet

“At this point, we know that one GPS station moved (8 feet), and we have seen a map from GSI (Geospatial Information Authority) in Japan showing the pattern of shift over a large area is consistent with about that much shift of the land mass,” said Kenneth Hudnut, a geophysicist with the U.S. Geological Survey (USGS).

Other sources are saying the average displacement is 8 feet along along a stretch of 300 miles, with a maximum displacement of 13 feet. The NASA image above shows the northeast coast of Honshu before and after the earthquake and tsunami. Scientists also say that the quake shifted the earth’s axis by nearly four inches.

Such shifts may not be so bad for auto navigation, thanks to lock to road features. But it’s certainly going to cause headaches for map-makers and may be disastrous for high-precision users such as surveyors. Marine charts will need revision as well, due to water depth changes.

None of this is meant to minimize the loss and destruction for the people of Japan. Our hearts go out to them.


When you think about it 8 feet is a tremendous distance for a landmass to move in such a short space of time. It certainly reminds us of how little we can do against the power of nature.



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