Updated 7:50 a.m. Thursday
For the second morning in a row, residents of the East Bay and beyond got a wake-up call from a small earthquake on the Hayward Fault.
The U.S. Geological Survey said the 3.5 quake that shook the area at 6:11 a.m. was centered just outside the Oakland portal of the Caldecott Tunnel.
That followed Wednesday's 3.4-magnitude, which occurred at virtually the same spot at 4:42 a.m.
Public reports to the USGS "Did You Feel It?" page show Thursday's temblor was felt -- mildly -- from Santa Rosa in the north to San Jose in the south and from the coast as far east as the Livermore Valley.
Just as it did on Wednesday, BART slowed trains Thursday to allow track inspections. Delays of up to 15 minutes were expected on the system.
In non-earthquake news, Thursday morning's quake was followed by a second round of naturally induced rumbling: a thunderstorm that rolled through the central Bay Area after 7:30 a.m.