Yes Virgina, that was an earthquake.
According to Janet Nguyen it was her remarks on Moorlach’s Pension ballot initiative. Maybe it was the indictment of Alaskan Senator Ted Stevens on corruption charges by a federal grand Jury. Or maybe it was a fault line somewhere around Chino that slipped up a little.
At any rate preliminay estimates from the USGS say it was a 5.4 magnitude quake.