Is the magnitude of the December 26th, 2004 Sumatra-Andaman Islands earthquake greater than 9.0?
Many detailed studies on the magnitude of the December 26th, 2004 Sumatra-Andaman Islands earthquake are being conducted. One careful study reports a magnitude as high as magnitude 9.3. Determining the magnitude of earthquakes larger than 9 is difficult, so several techniques are used and new techniques being developed. The magnitudes used by the USGS are either those that come from validated, routinely used techniques or from a consensus of the seismological community based upon such in-depth investigations. Since determining the magnitude of the Sumatra-Andaman Islands earthquake is still an active area of research, there is currently no firm consensus on the “correct” magnitude of this earthquake. The USGS magnitude is likely to change when a consensus is reached. This will be done in consultation the groups that provide routine information to USGS earthquake catalogs. One problem with prematurely revising the magnitude to 9.3 is that of consistency problems with our heavily-accesse
