Susan Hough is doing some work on it - she says:
The 10/16/99 M7.1 Hector Mine earthquake triggered earthquakes in and around the Salton Sea, including a M~5 event triggered by the mainshock S/surface waves. An investigation of the source properties of the triggered events has been submitted to the Bulletin of the Seismological Society of America. A preprint is available by request

A link to her page is below.

• Susan Hough Web Page