In March 2011 , a magnitude 9.0 earthquake struck off the east coast of Japan , dislodge the Earth ’s axis , and shortened days on Earth .
The earthquake – the most powerful on record to strike the country – shifted the planet ’s axis by about17 centimeters ( 6.5 inches ) , and may have moved the main islandby about 2.4 cadence ( 8 feet ) . Like other likewise enceinte temblor , it also changed the rotation speed of the Earth .
" quake can change the Earth ’s rotation by rearranging the Earth ’s volume . This is what a spinning methamphetamine skater does to make herself spin faster . She moves her arms closer to her body , she ’s moving her mass nigher to the axis about which she ’s splay , " Dr. Richard Gross of NASA ’s Jet Propulsion Laboratoryexplained to Popular Mechanics in 2011 . " And earthquakes do the same thing . "
" This seism must ’ve locomote the mass on average a bit snug to the Earth ’s rotation axis of rotation to make the Earth rotate faster and the distance of the day a bit smaller . "
By reckon at models of the Earth ’s mass distribution before the earthquake and using estimates of how the fault slipped during the earthquake , Gross was able-bodied to figure out how the mass distribution changed .
" Then , by conservation of angulate momentum , if I know how the Earth ’s mass was rearranged , then I know how the Earth ’s rotation must ’ve changed , " he added .
All in all , the earthquake pelt along up the rotation of Earth , byabout 1.8 microseconds(1.8 millionth of a 2nd ) . The Indonesian temblor in 2004 , for equivalence , sped up the Earth ’s twenty-four hours byan estimated 2.68 microseconds .
Earthquakes are not the only events and factors affecting the Earth ’s gyration speed .
" Any worldly event that involves the movement of mass affects the Earth ’s rotation , from seasonal conditions down to force back a railway car , " Dr. Benjamin Fong Chao , of NASA ’s Goddard Space Flight Center , excuse afterthe 2004 Indonesian temblor .
There are all sorts of factor that affect the speed of rotation , such aschanging sea levelsand shift within the Earth , though the biggest factor is that theMoon is move out from the Earth(who can blame it ) and as the two bodies interact , the result is the Earth slow up down , albeit withbursts of speed every now and then .
By see at ancient corals , scientists count on out that Earth used to spin a mass faster444 - 419 million geezerhood ago . Every Clarence Shepard Day Jr. , coral puts down a all right layer of calcium as it grows . Since coral grow more in the dry season than wet seasons , you may then weigh the lines of Ca carbonate deposits in each time of year and count on how many days demand place in a class . Using this method acting , the team worked out that Earth had 420 days a year 444 - 419 million geezerhood ago , before slowing down to the influence of our Moon .
