Earthquake rumbles through South Bay, felt miles way

An earthquake struck north of San Martin in Santa Clara County on Tuesday morning, which could be felt throughout the Greater Bay Area. 

The quake, downgraded to a 3.7 from a 4.0, struck about 7 a.m. A 3.6 aftershock was reported a minute or two later, according to the US Geological Survey. 

The quake was felt many miles away in Oakland, San Leandro, San Francisco, Foster City, according to people posting on social media. 

San Martin is south of San Jose, where one person tweeted he felt a "sharp jolt." 

There were no immediate reports of injury or damage.