A PIONEERING technique using data from GPS receivers has been used to make the first movie of an earthquake. The animation shows the Earth’s surface deforming during a magnitude 8.3 quake in September 2003 off the coast of Hokkaido in Japan.
Seismometers monitor quakes by measuring accelerations in the Earth’s crust. But the calculations required to turn accelerations into measurements of how the surface moved are tricky. Seismometers are sensitive to small accelerations but they cannot make accurate measurements of huge jolts.
GPS receivers are not as sensitive, but they are robust enough to work throughout a major quake. “They…
