Updated"
The USGS gives details of two earthquakes in the Baja region, Mexico.
At UTC 18:33 a 5.0 quake seems to have occurred at 28.931°N, 113.022°W, which is in the Gulf of California (a.k.a. Sea of Cortez) near and south of the island Angel de la Guarda. The second and larger quake, a 6.0 (preliminary) magnitude quake occurred at 29.568°N, 113.578°W is near the same island, but on the other side (north) of it.
It is fun to watch the news agencies get all confused. The only on the scene report we have is from about four hundred miles north-northeast, in San Diego, where the city hall got a bit rattled and was evacuated. It is also confusing the reporters that this place Baja is called "California" yet seems to be in Mexico. It would help if they knew how to spell the town reference in the USGS report, which you can read here.
That would be the Sea of Cortez not the Gulf of mexico, which is on the other side of the land mass.
Sorry, Greg, you did say Gulf (California).
S.R., right... that could be "gulf in Mexico" but not "Gulf of Mexico"... anyway, I've made it more specific.
I hope this isn't a predecessor.