California's San Andreas fault ripe for massive earthquake, study finds
Tectonic plate stress along San Andreas and San Jacinto fault lines at or above highest level in 1,000 years
Author of the article:Spiro Papuckoski
Published Jun 17, 2026 • Last updated 19 hours ago • 2 minute read
A landscape contorted by the San Andreas Fault is seen in the Mecca Hills on June 17, 2017 near Mecca, Calif.
A landscape contorted by the San Andreas Fault is seen in the Mecca Hills on June 17, 2017 near Mecca, Calif. Photo by David McNew / Files /Getty Images
Could Southern California be due for a massive earthquake in the not-too-distant future?
According to a study by earth scientists at the University of Hawai’i at Manoa, the tectonic plate stress along the San Andreas and San Jacinto fault lines in the state is at or above the highest level in 1,000 years.
California is bisected by the North American plate, which is generally moving in a southeasterly direction, and the Pacific plate, which shifts in a more northwesterly direction.
The fault stretches more than 1,300 kilometres from Eureka along the coast of the Pacific Ocean in the north to the Salton Sea in the south.
Highly-populated areas along fault
A large seismic event could trigger widespread damage in highly-populated areas of the state such as Los Angeles, San Bernardino, Riverside and the Coachella Valley.
“Our results show that stress levels on multiple fault segments are now at or above the highest values seen in the past millennium and that the region may be capable of a large through-going rupture involving both fault systems,” Liliane Burkhard, the study’s lead author, told the school’s website.
“We also found that Cajon Pass may act as an ‘earthquake gate’: sometimes blocking large ruptures from crossing between the faults, and sometimes allowing them to pass through and involve both systems in a single event.”
Notable past disasters
Notable disasters caused by seismic activity along the fault line include the quake that hit and severely damaged San Francisco in 1906, another less serious event in 1989, and a major upheaval in the Los Angeles suburb of Northridge in 1994.
The study, published in the Journal of Geophysical Research: Solid Earth, used computer models to simulate the pressure on the plates built up and released in the southern portion of the fault zones based on past earthquakes and geological evidence dating back 1,000 years.
Results from the study suggest geological conditions are ripe for the Big One, but researchers warn a massive earthquake is not imminent.
‘Not a prediction’
“This is not a prediction of when an earthquake will happen,” said Burkhard, research affiliate in the Hawai’i Institute of Geophysics and Planetology at the UH Manoa School of Ocean and Earth Science and Technology.
“However, studies like this are important contributions to national and global earthquake hazard research in that we are using rigorous, quantitative science to better understand the risk facing millions of people. What we can say is that the system is critically stressed, and that physics-based models like this one give us a clearer picture of the range of scenarios we should be prepared for. That information matters for hazard assessments, infrastructure planning, and emergency preparedness.”
The fault line has been active recently with more than 350 small earthquakes recorded in Southern California near the border with Mexico last month, reports Fox affiliate KSWB.
torontosun.com
Tectonic plate stress along San Andreas and San Jacinto fault lines at or above highest level in 1,000 years
Author of the article:Spiro Papuckoski
Published Jun 17, 2026 • Last updated 19 hours ago • 2 minute read
A landscape contorted by the San Andreas Fault is seen in the Mecca Hills on June 17, 2017 near Mecca, Calif.
A landscape contorted by the San Andreas Fault is seen in the Mecca Hills on June 17, 2017 near Mecca, Calif. Photo by David McNew / Files /Getty Images
Could Southern California be due for a massive earthquake in the not-too-distant future?
According to a study by earth scientists at the University of Hawai’i at Manoa, the tectonic plate stress along the San Andreas and San Jacinto fault lines in the state is at or above the highest level in 1,000 years.
California is bisected by the North American plate, which is generally moving in a southeasterly direction, and the Pacific plate, which shifts in a more northwesterly direction.
The fault stretches more than 1,300 kilometres from Eureka along the coast of the Pacific Ocean in the north to the Salton Sea in the south.
Highly-populated areas along fault
A large seismic event could trigger widespread damage in highly-populated areas of the state such as Los Angeles, San Bernardino, Riverside and the Coachella Valley.
“Our results show that stress levels on multiple fault segments are now at or above the highest values seen in the past millennium and that the region may be capable of a large through-going rupture involving both fault systems,” Liliane Burkhard, the study’s lead author, told the school’s website.
“We also found that Cajon Pass may act as an ‘earthquake gate’: sometimes blocking large ruptures from crossing between the faults, and sometimes allowing them to pass through and involve both systems in a single event.”
Notable past disasters
Notable disasters caused by seismic activity along the fault line include the quake that hit and severely damaged San Francisco in 1906, another less serious event in 1989, and a major upheaval in the Los Angeles suburb of Northridge in 1994.
The study, published in the Journal of Geophysical Research: Solid Earth, used computer models to simulate the pressure on the plates built up and released in the southern portion of the fault zones based on past earthquakes and geological evidence dating back 1,000 years.
Results from the study suggest geological conditions are ripe for the Big One, but researchers warn a massive earthquake is not imminent.
‘Not a prediction’
“This is not a prediction of when an earthquake will happen,” said Burkhard, research affiliate in the Hawai’i Institute of Geophysics and Planetology at the UH Manoa School of Ocean and Earth Science and Technology.
“However, studies like this are important contributions to national and global earthquake hazard research in that we are using rigorous, quantitative science to better understand the risk facing millions of people. What we can say is that the system is critically stressed, and that physics-based models like this one give us a clearer picture of the range of scenarios we should be prepared for. That information matters for hazard assessments, infrastructure planning, and emergency preparedness.”
The fault line has been active recently with more than 350 small earthquakes recorded in Southern California near the border with Mexico last month, reports Fox affiliate KSWB.
California's San Andreas fault ripe for massive earthquake, study finds
Could Southern California be due for a massive earthquake in the not-too-distant future? Read more.
