Some large quakes within the Gulf of California a short time ago, with the largest preliminary magnitude at 6.9. They all happened within a few minutes of each other, so I expect the reported magnitudes will change as they sort out the data. The closest town is Santa Isabel in Baja California, 76 miles away. A 5.8 shock preceded the 6.9 event, which was followed by aftershocks at 6.0 and 5.0 magnitude.
The Gulf of California is the result of divergence, where Baja is sliding northwest and separating from the Mexican mainland. The movement of Baja is intimately related to motion on the San Andreas fault in California, as Baja and all the lands in Alta California west of the San Andreas are part of the Pacific Plate, which is shifting northwest at around 2 inches a year.
It's a good reminder that California is earthquake country, and that enough stress has built up on different sections of the San Andreas fault to produce major quakes. You can read lots more about earthquake hazards at http://earthquake.usgs.gov/.