In the midst of all the loss and continued danger for the people of Japan, other stories are beginning to come out related to earthquake science. One that caught my eye was this – a GPS monitoring station has shown a shift of eight 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.
About Rich Owings
One TV report gave the axis movement as 1cm. What is the official number? Thanks.
I think you’ll see different researchers reporting different results for awhile. Here’s one that says 6.5″, and it also says the quake shifted day-length…
http://www.geek.com/articles/geek-cetera/japan-quake-effects-length-of-day-and-gps-coordinates-20110314/