Automated near-realtime CMT inversion,
H. Kawakatsu
Geophys. Res. Lett., 22,
2569-2572, 1995.
Abstract
The Earthquake Research Institute (ERI) of the University of Tokyo
has completely automated the process of determining source mechanisms
of earthquakes using waveform data.
The solutions are automatically distributed using the Internet
without being checked.
The process is initiated by receipt of e-mail giving
the origin time and location of an earthquake.
To determine the source mechanism, we apply
the Harvard centroid moment tensor (CMT) inversion method
to long-period body wave data
(the portion of the seismogram from the first arrival to the initial
surface wave).
The method has been successfully applied since October 1993
to all of the major earthquakes in the world for which we received
event e-mail.
108 of the 242 CMT solutions in 1994
were determined within 6 hours of the event,
with an average delay of 3.8 hours.
For local events (e.g., events around Japan),
it is also possible to determine CMT solutions within
30 minutes from the occurrence of the earthquakes, using an efficient
dialup data retrieval system operated by ERI.