Using Stellarium I set the longitude and latitude to the same longitude and latitude as the Vanuatu 6.1 EQ just off the coast from Port Vila yesterday as reported on Google Earth.
I then wound the time back to the same time as the EQ (Thursday February 28 2013, 03:09:44 UTC.)
Guess what Comet was rising dead on the horizon line to the North.
Yep C/2012 S1 (ISON)!
I also completed the same exercise for the 6.9 in the Kuril Islands later the same day this time C/2012 S1 (ISON) was about 30 degrees above the horizon and about 30 degrees away from Jupiter on the elliptic (Path Planets & Sun Appear to move in) as Jupiter came over the horizon.
So there is an argument its gravitational vector when combined with other planets do create create plate forces. If a potential EQ site under tension rotates into that vector it will unzip and release the potential energy stored up in the locked plates as a shallow EQ.
Jupiter will cross C/20012 S1 (ISON's) orbital plane on the 22 April 2013. That looks a particularly deadly day for EQ's as Venus is lined up in opposition at right angles to a line joining Mercury, Sun, Earth and Mars.
[
link to ssd.jpl.nasa.gov]
I just saw the Kuril Islands get ripped again I'll check it out!