The recent 8.9 magnitude earthquake off the coast of Japan, which produced the tragically destructive tsunami, reportedly had some planet wide effects. It affected the length of the day; redistributed a small amout of the Earth’s mass; and moved the position of Japan vis-a-vis North America.
According to a report on Space.com, geophysicist Richard Gross at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., reports that the length of the day was shortened. The day length difference is not large enough for navigators to notice, however. A day will only be 1.8 microseconds shorter than before.
The earthquake also redistributed the earth’s mass, causing the earth’s figure axis to shift roughly 6 1/2 inches. The figure axis is the axis through the figure of the earth, not the rotational axis. While the rotational poles didn’t shift, the change in the figure axis means the earth will wobble a bit more, but the amount of added wobble will be far too small to affect celestial navigation using the Nautical Almanac.
The quake reportedly also affected the position of Japan relative to North America. According to preliminary numbers complied by the U.S. Geodetic Survey, the movement of the plate on which Japan rides brought the country approximately eight feet closer to the U.S.
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Earthquake shifts Earth
