At least two significant aftershocks have followed a 6.5 magnitude earthquake that struck just off the Northern California coast Thursday morning.

According to the US Geological Survey, the initial quake occurred at 6:49 a.m. Thursday in the waters 104 miles west of Eureka. It had a depth of 12.1 kilometers.

The aftershocks, according to the USGS, struck at 8:32 and 8:33 a.m.. The first was a 5.0 magnitude quake with an epicenter in the same area and a depth of 4.3 km, the second was a 4.1.

All occurred on the Mendocino fault, according to the USGS. It runs about six miles beneath the ocean floor.

A smallish number of users of the USGS's "Did You Feel It?" map appeared to actually feel it, which isn't surprising given how far from the coast the quake's epicenter was. However, some users of social media clearly did:

There's no tsunami danger as a result of the earthquake, according to the USGS, and no damage has been reported. Out of an abundance of caution, however, BART briefly halted following the incident, then reduced speeds on its trains this morning to ensure all of its trackway remained intact following the quake.