Imaging the earthquake

Seismologists are using a new method to detail the processes that unfolded during the disastrous Sumatra-Andaman earthquake in the Indian Ocean on December 26, 2004.

Scientists at Scripps Institution of Oceanography at the University of California, San Diego, in collaboration with scientists at the University of California, Los Angeles, have developed a new method for imaging how the earth ruptured during the quake, which is providing a fresh perspective of the massive event.

The new method traces seismic waves back to their original rupture source. It makes use of the Japanese Hi-Net array, consisting of about 700 high-quality seismometers, as antennae to track the seismic sources.

"If you were at a pond and dropped a pebble, you would see a ripple appear in the water. If another person only saw the ripple, they could still probably guess where you dropped the pebble by tracing the rings back to the centre. That's exactly what we are doing. We are looking at how the ring of seismic waves is approaching the array to find out where the rupture is occurring," said Scripps’ Miaki Ishii.