Mouse over this USGS earthquake map to see the names of the fault lines (in red) nearest you. Zoom in and click on the South Napa quake for more specific location data and to view a map showing the quake’s geographical intensity range. Zoom out to see the locations and sizes of other recent earthquakes around the world. View a full-screen version of the map here.
For more on the science of earthquakes, check out KQED’s free e-book.