File talk:2010 Chile earthquake epicenter.png

This NASA nonsense about the quake shortening the length of day needs to be addressed. If every "thrust" quake shortened the day by reducing the earth's moment of inertia, well the earth would speed up all right, and tend to become more oblate, i.e., fatter, not skinnier. These NASA scientists have the earth pulling itself together by its own bootstraps. We have 1) unverifiable speculation on the length of day; 2) verifiable but unverified (non-NASA)speculation on the raising of Isla Santa Maria by two meters; 3) actual GPS measurement of Concepcion having moved 3 meters to the west. Accordingly Concepcion's sidereal time was delayed 8.1 milliseconds, and it would take thousands of years for the city to catch up with its former time if its day were shortened according to NASA predictions.

Some things do affect the earth's rotation against the usual deceleration, like the accumulation of snow in northern latitudes during winter. Sea level drops a few mm--more in the north than in the south, and the polar (i.e., the lithospheric, not total) diameter shrinks a tiny bit, but the earth's center of gravity shifts northward. There is both an elastic and an inelastic response in the lithosphere. These things happen on a much larger scale as the earth goes in and out of ice ages, and post glacial rebound counteracts the effect of receding ice sheets late in the melting stage.

But all in all the earth tries to stay round, and is affected primarily by gravity and rotation. As the rotation decreases over the aeons it gets rounder, but any phenomena claimed to alter the orb's moment of inertia must be assumed both to have no equal and opposite counterpart to act on it, but to alter the geoid generally. Furthermore the repeated actions of these tectonic thrusts into the earth must be supposed to be continually accelerating the globe, so that in a world unaffected by decelerating tides we would have to postulate a continual acceleration and increased bulging due to this type of earthquake.

It all seems pretty far fetched, but it becomes easier to understand how many at NASA and NOAA tend to position themselves on the side of Catastrophic Climate Change. --A G Foster