Chile quake shift Earth's axis

A NASA scientist said that Chile earthquake may have changed Earth's rotation and shortened the length of days.

Chile quake is recorded as seventh strongest earthquake in recorded history. It killed more than 700 people and caused widespread devastation. On rikhtar scale it goes to 8.8 magnitude.

NASA scientist Richard Gross (NASA's Jet Propulsion Laboratory in Pasadena, Calif) said that Chile quake should have sortened the length of an Earth day by 1.26 milliseconds.

Richard Gross and his colleagues has made a computer graphics to determine the effects of that quake. Found that it should have moved Earth's figure axis by about 3 inches (8 cm or 27 milliarcsonds).

We know that Earth's figure axis is not the same as its north-south axis, which it spins around once everyday at a speed of about 1,000 mph (1,604 kph). The figure axis is the axis which the Earth's mass is balanced perfectly. It is offset from the Earth's north-south axis by about 33 feet (10 meters).

In the news I found more information on this situation.

Strong earthquakes have altered Earth's days and its axis in the past. The 9.1 Sumatran earthquake in 2004, which set off a deadly tsunami, should have shortened Earth's days by 6.8 microseconds and shifted its axis by about 2.76 inches (7 cm, or 2.32 milliarcseconds).

One Earth day is about 24 hours long. Over the course of a year, the length of a day normally changes gradually by one millisecond. It increases in the winter, when the Earth rotates more slowly, and decreases in the summer, Gross has said in the past.

The Chile earthquake was much smaller than the Sumatran temblor, but its effects on the Earth are larger because of its location. Its epicenter was located in the Earth's mid-latitudes rather than near the equator like the Sumatran event.

The fault responsible for the 2010 Chile quake also slices through Earth at a steeper angle than the Sumatran quake's fault, NASA scientists said.

"This makes the Chile fault more effective in moving Earth's mass vertically and hence more effective in shifting Earth's figure axis," NASA officials said.

Gross said his findings are based on early data available on the Chile earthquake. As more information about its characteristics are revealed, his prediction of its effects will likely change.

This measure of shift might not sound anything major, but in reality it is!

Let's see some Chile earthquake's bigger images at Boston Bigpicture.