SAN FRANCISCO - A magnitude-3.7 earthquake was reported by the United States Geological Survey to have occurred beneath San Francisco International Airport Friday evening, leading the ground to rattle across most of the Bay Area.
According to seismologists, the shaking was felt around 6:30 p.m. local time and was centered more than 8 miles below the surface of San Mateo County.
Earthquakes that register less than a magnitude-4.0 are considered to be minor and usually result in little to no damage.
Due to the minor nature of the quake, alerts to cell phones notifying Californians did not populate, as typically happens before quakes with a magnitude of 4.5 or greater.
Local authorities did not immediately report any damage associated with the quake, but travelers did experience delays while safety inspections were conducted on infrastructure.
The San Francisco Bay Area Rapid Transit District said trains were operating at reduced speeds while system inspections took place.
The San Francisco International Airport is located just about three miles away from the infamous San Andreas Fault, and engineers said cutting-edge seismic designs were used in the construction of structures, including the 220-foot-tall control tower.
According to the Maffei Structural Engineering group, the airport's control tower meets all FAA criteria for extreme earthquakes and, at the time of construction, was the tallest structure built with a unique design to withstand violent shaking.
The National Earthquake Information Center reports California experiences thousands of earthquakes every year, but less than a handful register a magnitude 5.5 or greater and cause substantial damage.