A 4.6 magnitude earthquake shook Santa Cruz County early Thursday morning, according to the United States Geological Survey. The earthquake was initially registered with a magnitude of 4.9 but was downgraded to magnitude 4.6 shortly after 2:45 a.m. It initially hit at around 1:40 a.m. and was cen tered in the Boulder Creek area of the Santa Cruz Mountains, according to the USGS. The earthquake was also felt in the South Bay, including parts of San Jose, Los Gatos, and Santa Clara, as well as in other regions of the Bay Area. There were no immediate reports of serious damage. Some residents said they were first awakened by earthquake alerts on their phone, then felt their beds and windows shake. A surveillance camera inside a home in Felton, which is located about five miles from Boulder Creek, captured the early-morning jolt. Homeowner Keith Swick said the quake not only knocked items off his shelves but caused some separation in one of the wood beams in his ceiling and a crack in the paint on one of his walls. “We automatically assumed it was a giant tree that fell, and then it felt like it actually hit the house because it made so much noise and it shook the whole house,” he said. “We finally looked at our phones eventually and we saw that there was an earthquake, so that added up. It was pretty violent.” At a drug store in Boulder Creek, Karen Simonson had to clean up a small mess on the ground after deodorant sticks and other toiletries fell off shelves. “It was enough to wake you up,” she said. “You could hear the shaking. It was definitely a wake-up, I’m sure for everybody.” The quake is believed to have originated just west of the San Andreas Fault. No significant aftershocks have been reported in the area. You can track the latest earthquake activity via our real-time quake tracker here. In February, a series of small earthquakes rattled the East Bay. The most powerful quake was a magnitude 4.2 that struck south of San Ramon, according to the USGS. At least a dozen other smaller quakes struck in the same area. The area has experienced earthquake swarms — when multiple small magnitude earthquakes strike over a short period of time — for decades, according to seismology experts. The Associated Press contributed to this report. BAY AREA QUAKE CENTRAL You can take steps to plan and prepare for the next big one. Access our Bay Area Quake Tracker, the latest earthquake stories, extensive quake prep checklists, videos and many other disaster preparedness resources all in one place: NBCBAYAREA.COM/QUAKES This story uses functionality that may not work in our app. Click here to open the story in your web browser. ...read more read less