Stress on the southern San Andreas fault has reached its highest level in 1,000 years, researchers said [1].
The findings highlight an increased risk of a major rupture in Southern California, where tectonic pressure has accumulated at the boundary of the Pacific and North American plates [1].
The research focused on the 1,300 km long San Andreas fault [1]. Scientists simulated a worst-case scenario known as the "Big One," depicting a magnitude-7.8 earthquake occurring along the southern segment [2].
According to the simulation, such an event would produce about two minutes of strong shaking [1]. The resulting catastrophe is estimated to cause hundreds of deaths and economic damages reaching up to $1 trillion [2].
Large earthquakes on the San Andreas fault occur approximately every 150 years on average [2]. The last comparable large earthquake on this fault occurred in 1857 [2].
Researchers said that recent strong earthquakes across the Ring of Fire—the circum-Pacific belt of volcanoes and seismic activity—have increased concerns regarding global seismic stability [1].
“Stress on the southern San Andreas fault has reached its highest level in 1,000 years”
The gap between the last major rupture in 1857 and the current date exceeds the average 150-year recurrence interval for the San Andreas fault. Combined with the reported millennium-high stress levels, this suggests the region is significantly overdue for a major seismic event, placing immense pressure on California's urban infrastructure and emergency preparedness systems.
