In addition to causing widespread death and destruction, last week’s devastating earthquake in Chile may have shifted the Earth’s axis permanently and created shorter days, according to scientists at NASA. Based on calculations thus far, every day from now on should be 1.26 microseconds shorter. While the change probably won’t be affecting our daily schedules too much (a microsecond is a millionth of a second), it is unsettling to think about how much impact something as concentrated as an earthquake can have on the entire planet.
How does an earthquake move the planet’s axis? A sizable quake can shift huge amounts of rock, changing the distribution of mass on the planet. That change alters the rate at which the planet rotates, and rotation determines a day’s length. Scientists explained that the key to the shift was the location of the quake, and the fact that the fault sliced through Earth at a steeper angle, making “the Chile fault more effective in moving Earth’s mass vertically and hence more effective in shifting Earth’s figure axis.”
The Chile earthquake isn’t the first or the only natural disaster that changed the Earth’s shift. In fact, a day’s length was shortened by 6.8 microseconds after the tsunami of 2004. Benjamin Fong Chao of NASA’s Goddard Space Flight Center in Greenbelt, Maryland explained in 2005, “Any worldly event that involves the movement of mass affects the Earth’s rotation.”