Date: December 26, 2004. A massive earthquake in Indonesia accelerated the Earth’s rotation and changed the shape of our planet . NASA (National Aeronautics and Space Administration) scientists have calculated that the earthquake slightly changed the shape of our planet. In addition, it took almost 3 milliseconds from the length of the day and shifted the North Pole by a few centimeters .
Dr. Benjamin Fong Chao of NASA Goddard Space Flight Center and Dr. Richard Gross of NASA’s Jet Propulsion Laboratory is routinely studying earthquakes. Earth’s rotation is constantly changing not only as a result of earthquakes, but also due to greater changes in atmospheric winds and ocean currents. Earthquakes generally affect the Earth’s rotation, but for the most part their effects are barely visible.
Unfortunately, this earthquake was not ordinary. Most people know him because of the catastrophic consequences – more than 200,000 deaths , millions affected. The devastating impact of this earthquake reached 9 degrees on a new “torque” scale (modified Richter scale), making it the sixth most devastating earthquake in recorded history. earthquake December 26, 2004, magnitude 9.0 Indonesia
Chao and Gross routinely calculate the effect of earthquakes on the shape of the Earth and its rotation. They also study changes in polar motions – ie the shift of the North Pole.
According to their latest calculations, the earthquake of 26 December 2004 shifted the “average North Pole” of the Earth by 2.5 cm in the direction of the 145 meridians (towards New Guinea in the Pacific Ocean). This shift is a continuing long-term seismic trend observed in previous studies.
The earthquake also affected the shape of the Earth. Chao and Gross calculated that the flattening of the Earth (flattened at the top and erupted at the equator) had decreased slightly – by about one part in 10 billion. This follows a long-term trend that shows that earthquakes make the Earth less flattened. Less flattened means more oval.tidal wave earthquake
They also found that the earthquake shortened the length of the day by 2.68 microseconds (microsecond is a millionth of a second). In other words, the Earth is spinning a little faster than before. This change in speed is related to the change in flattening. It’s like a figure skater in a pirouette pulling his hands to his body, which results in an increase in spin speed.
None of these changes were measured – only calculated. But Chao and Gross hope that these changes will be reflected in the revision of Earth’s rotation data from ground-based and satellite sensors.