The likelihood of a huge magnitude-8 or higher earthquake striking California within the next 30 years has jumped from 4.7 percent to 7 percent according to a new forecast released by the U.S. Geological Survey.

As the USGS examined multi-fault ruptures where earthquakes aren’t confined to individual faults, scientists there determined that they presented a “significant advancement in terms of representing a broader range of earthquakes throughout California’s complex fault system,” USGS scientist Ned Field said according to a CBS Los Angeles report.

The USGS estimated back in 2008 that earthquakes of about a magnitude-6.7 would likely hit the state every 4.8 years, but the new report expands that to 6.3 years. However, the likelihood of “the big one” has increased from 4.7 percent to 7 percent over the next 30 years.

Seismic activity has been fairly low in California for the past century, but the risk of a big earthquake is increasing in the San Andreas fault system, making ‘The Big One’ all but inevitable in the coming years, according to the report.

An 8.0-magnitude earthquake would be the largest earthquake to strike California since 1700, when an magnitude-9 earthquake — the same size as the quake that rocked Japan in 2011 — is the largest known earthquake to have occurred in the lower 48 United States. An 8.0 quake would be the second largest, and the largest since the United States was formed as a nation.

The worst of the 20th century was a 7.8-magnitude quake in San Francisco in 1906, which resulted in devastating fires that lasted for days and killed 3,000 people and destroyed 80 percent of the city.

Even the famous 1989 Loma Prieta earthquake, which interrupted the World Series and caused massive damage in San Francisco, was only a 6.9-magnitude quake. The most recent quake to top 7 was the 2010 Baja California earthquake.