USGS says Oaxaca .... that’s where they are.
http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc0008m6h.html
Story on them being there. Let’s hope everything is ok for them and all else there.
Oaxaca is the region where the quake was at. The articles put them in the city Oaxaca, which as posted above is 110 miles from the epicenter (101 according to USGS on the link you posted). Hopefully they didn’t take a day trip to the southwest.