A record total of more than 10 million people were expected to "drop, cover and hold on" Thursday morning as they took part in the annual "Great ShakeOut" earthquake drill in California.
The event, which aims to improve earthquake preparedness, was scheduled to take place at exactly 10:16 a.m. in schools, homes, businesses and workplaces throughout the state.
It comes just days after a study was released that indicated four fault lines beneath the heavily populated Bay Area were overdue for an earthquake and were capable of producing a temblor of magnitude-6.8 or greater in the near future.
The four fault segments were part of the San Andreas Fault, which runs from northern California to the Cajon Pass near San Bernardino.
One of the fault lines was located near key important dams and aqueducts that supply a major portion of the state's water, and a major temblor along it had the power to impact the water supplies of the Bay Area to Southern California, the Associated Press reported.
Roughly 10.3 million people have registered to participate in the ShakeOut, which has been held every year since 2008.
Of those participants, 4.5 million were in Los Angeles, Orange and Ventura counties, while about 1.3 million were in Riverside and San Bernardino counties, according to figures posted to the event's website.
According to a news release from the Earthquake Country Alliance, the recent Napa earthquake, the 20th anniversary of the Northridge quake and the 25th anniversary of the Loma Prieta temblor were also all "critical reminders" that California was "Earthquake country."
Roughly 9.3 million took part in the 2013 drill.