When a colleague asked me (they always ask me - I'm "Mr. Science") whether Sunday's earthquake was big enough to shift Earth's axis, I uttered an explitive related to equine excrement. I had visions of Velikovsky. But a seismologist disabused me of that notion, explaining that the effect, while small, is measurable. Now a team from JPL has done the calculations:
The change was caused by a shift of mass towards the planet's centre, as the Indian Ocean's heavy tectonic plate lurched underneath Indonesia's one, say researchers at NASA's Jet Propulsion Laboratory in Pasadena, California. This caused the globe to rotate faster, in the same way that a spinning figure-skater accelerates by tucking in her arms.The blast literally rocked the world on its axis, add Richard Gross and his NASA colleagues. They estimate that Earth now tilts by an extra 2.5 centimetres in the wake of the jolt.