Not per "trigger". It would be easy enough, though, to have a script look at
the appropriate logfile (/var/log/auth.log in Slackware) and grep for the user
name and login-method in a timed loop, and send an e-Mail on success (of course,
you'll want to check the time-stamp, too, and keep it as a flag so you don't
get re-alerted for the same event every XX seconds :}).