On December 26, 2004 there was a magnitude 9.3 earthquake in the Indian Ocean, off the coast of Sumatra. It caused a powerful tsunami that devastated the coastal regions of several countries and killed 240,000 people. News of the tsunami's destructive powers quickly made the rounds in the news media. We watched in horror and dismay the extent of the devastation. The earthquake registered 9.3, stronger than the one in Maule, Chili in February 2010, which was registered at 8.8. The 8.8 Chili quake was so strong that it shifted the Earth's crust, redistributing mass on such a scale that, according to NASA, it caused a shift in the Earth’s axis! The shift has been estimated at 8 centimeters, which affected the rate of the Earth's rotation and shortened the length of our day by some 1.26 microseconds.
As tremendous as the Chili quake was, the 2004 quake was stronger. But far stranger and much less reported—forty-four hours after the quake, NASA's newly launched Swift satellite, the Very Large Array, and other observatories picked up the arrival of a powerful gamma ray burst. A hundred times stronger than any gamma burst previously recorded, this one was as bright as a full moon, but radiated most of its energy in gamma wavelengths. This gamma burst temporarily altered the shape of our ionosphere and distorted radio transmissions. We tracked this gamma burst to activity in the neutron star SGR 1806-20, a soft gamma ray repeater, in the constellation Sagittarius, approximately 10 degrees northeast of the Galactic Center or about 45,000 light years from us.
Less than forty-eight hours after the biggest earthquake in twenty five years, a very intense gamma ray burst hit our planet! This gamma burst was 100 times brighter than anything we had seen in the twenty-five year history of gamma ray observation. Were these two highly unusual events related? We don't know how or why they would be, though it has been postulated that gravitational waves might have been a factor that set the earthquake into motion. Perhaps the gamma rays, that we monitored, were slowed down by scattering off dust particles, cosmic rays and such, making them proportionately slower than unimpeded gravitational waves that they might have been traveling with. Or perhaps the gravitational waves were going at superluminal speed—also a possibility—hitting the earth and setting off the quake and tsunami before the gamma rays could catch up. At this point who knows?