Two small Earthquakes were recorded near Lake Oroville in the last 24 hrs, which appear to be a result of the fast lake level changes, and the subsequent release of pressure from water weight. Note the two yellow dots on the USGS map below:
Source of map, here
JD Elam notes on Facebook:
The predicted earthquakes due to extreme lake level change have started. 2 in the last hour. 300,000,000 pounds of water has been removed in two days, that will cause the earth to jiggle a bit. These were predicted and should not cause any problems.
The magnitude of the quakes were very small, 0.8 and 1.0 on the Richter Scale, and there does not appear to be any threat to the dam infrastructure.