California Faces Seismic Shakes and Coastal Flooding as Hurricane Marie Brings Heavy Rain to Los Angeles County

On Sunday, September 6 2026, residents of Los Angeles County experienced a series of weather‑related disruptions and a minor earthquake. A 3.2‑magnitude tremor struck just south of Compton at 7:13 a.m. local time, while the National Weather Service issued a flood advisory for west‑central portions of the county and a high‑surf advisory that had been in effect since Saturday.

The earthquake’s epicenter lay 4 km southeast of Compton, directly over the Newport‑Inglewood Fault Zone, a prominent urban fault line in Southern California. The event occurred at a depth of 12.8 km and was felt by 1,113 people, with a maximum intensity of MMI 3.5. The U.S. Geological Survey recorded the magnitude as 3.2 and noted the shallow depth and the number of people who reported feeling the shake.

Earlier in the week, a 3.4‑magnitude quake rattled the Inland Empire near Ontario, San Bernardino County, on Wednesday, September 2. The USGS reported the tremor struck at 5:37 a.m. local time, with an epicenter roughly 4 miles southeast of Ontario and a depth of about 4 miles. The quake was felt across the county, which is part of the larger Riverside‑San Bernardino‑Fontana metropolitan area.

The weather‑related alerts were tied to Hurricane Marie, a distant Pacific storm that was still well offshore but sending a swell toward Southern California. The National Weather Service issued a Coastal Flood Advisory for Los Angeles County beaches that began at 6 a.m. on Saturday, September 5, and remained in effect through Tuesday, September 8. The advisory warned of rising tide levels and the potential for flooding along the coast.

Simultaneously, a high‑surf advisory was in effect for all Los Angeles County beaches from Saturday through Tuesday. The advisory cited waves of 5 to 8 feet, with a high rip‑current risk. The National Weather Service also issued a flood advisory that lasted until 1 p.m. Sunday afternoon for west‑central Los Angeles County, including the Franklin and Palisades burn scars.

The flood advisory was prompted by prolonged downpours that had saturated the region. The Los Angeles County Department of Public Health issued an ocean‑water‑quality advisory for all county beaches until at least 2 p.m. Wednesday, warning beach users to avoid water contact for at least 72 hours after rainfall.

These events underscore California’s vulnerability to both seismic and weather‑related hazards. Los Angeles County, the most populous county in the United States with nearly 9.7 million residents, sits on several fault lines, including the Newport‑Inglewood Fault. San Bernardino County, the largest county by area in the contiguous United States, also experiences frequent seismic activity.

The combination of a hurricane‑driven swell, heavy rainfall, and coastal flooding has prompted local authorities to urge residents to remain vigilant. The National Weather Service and the California Department of Transportation have advised that beachgoers check current advisories before heading to the shore and that motorists be prepared for potential road closures or flooding.

While the 3.2‑magnitude earthquake in Compton was minor and caused no reported damage, the 3.4‑magnitude quake near Ontario was felt more widely across the Inland Empire. Both events were recorded by the USGS, which maintains real‑time monitoring of seismic activity throughout California.

The high‑surf and flood advisories remain in effect through Tuesday, September 8, as Hurricane Marie continues to influence weather patterns along the Southern California coast. Residents and visitors are encouraged to monitor updates from the National Weather Service and local emergency management agencies.

In summary, Los Angeles County experienced a minor earthquake and weather‑related flooding on September 6 2026, while the broader region faced seismic activity in early September and ongoing coastal hazards tied to Hurricane Marie. The state’s emergency services continue to monitor both seismic and weather conditions to protect residents and infrastructure.