Karmactive Staff
Govind Tekale
Several earthquakes were recorded in Oregon, California, South Carolina, Greece, and Japan between September 8-9, 2025. Officials report no tsunami threat from the Oregon quake and no major damage from any of the events so far.
Earth Moves From Pacific to Mediterranean
The largest recent quake occurred offshore Oregon along the Blanco Fracture Zone, measuring magnitude 5.8 at approximately 4:08 p.m. UTC (10:08 p.m. local time) on September 8, 2025, at a depth of 13 km (8 miles). A magnitude 4.9 aftershock followed within 15 minutes. The U.S. Tsunami Warning System confirmed no tsunami threat exists from these events.
“Earthquakes along the Blanco Fracture Zone are common and typically don’t generate tsunamis due to the horizontal movement along the fault,” according to seismologists. The transform fault nature of the Blanco Fracture Zone means it primarily produces side-to-side movement rather than the vertical displacement needed to generate tsunamis.
Southern California recorded two separate quakes: a magnitude 3.5 near La Verne in Pomona Valley on September 6 and a magnitude 3.3 near Pearblossom in the Palmdale area on September 9. Both were shallow events with felt reports across Los Angeles County but no damage reported. The La Verne quake occurred at a depth of 7.7 km, while the Pearblossom event was at 8.99 km depth.
In Greece, a magnitude 5.2 earthquake struck near Nea Styra on Evia island on September 9. The shallow tremor was felt in Athens, approximately 40-50 km away, according to the Athens Geodynamic Institute.
Japan’s Chiba region near Kisarazu experienced a magnitude 4.0-4.3 earthquake at approximately 70 km depth on September 9, resulting in limited felt reports despite the moderate magnitude.
South Carolina’s Greenwood County has recorded approximately a dozen small earthquakes in late August 2025, centered near Coronaca and Lake Greenwood, with the largest registering around magnitude 3.0. The earthquake swarm—rare for the region—prompted the South Carolina Emergency Management Division to urge residents to review earthquake preparedness steps.
Different Faults, Different Behaviors
These earthquakes occurred on separate fault systems across different tectonic plates. The Oregon event happened along the Blanco Fracture Zone, a transform fault between the Pacific and Juan de Fuca plates that experiences regular seismic activity.
The South Carolina swarm occurs in what geologists call the Eastern Piedmont region, where small earthquake clusters occasionally happen without a clear main shock.
“Earthquake swarms differ from aftershock sequences,” states USGS documentation. “Swarms consist of multiple events of similar size, while aftershock sequences follow a larger main event and gradually decrease in frequency and magnitude.”
Exact depth measurements from official sources show:
- Oregon offshore: 13 km
- La Verne, California: 7.7 km
- Pearblossom, California: 8.99 km
- Nea Styra, Greece: 2.3-13.6 km (varies by reporting agency)
- Kisarazu, Japan: 70 km
- Greenwood County, SC: 2-5 km range
Historical Context Matters
The Blanco Fracture Zone near Oregon has experienced several earthquakes of magnitude 5.5 or greater in the past two years. The most recent significant event prior to this was a magnitude 6.0 on October 30, 2024, according to the USGS.
South Carolina’s most powerful historical earthquake was the 1886 Charleston earthquake, estimated at magnitude 7.0, which caused 60 deaths and widespread damage. The current Greenwood County swarm occurs in a region that typically experiences low to moderate seismic activity.
Greece’s seismically active Evia region experiences frequent earthquakes, with the Athens Geodynamic Institute noting that the recent quake occurred in an area “not known for producing large earthquakes.”
Safety Measures During Earth Movement
USGS and Federal Emergency Management Agency safety guidance includes:
Drop to the ground before the earthquake drops you. Take cover under sturdy furniture. Hold on until shaking stops.
After shaking ends, check for injuries and structural damage. Inspect for broken glass, damaged electrical wiring, water leaks, and gas odors. If gas is detected, open windows, leave immediately, and notify authorities.
“Emergency supplies should include water, non-perishable food, medications, flashlights, batteries, and first aid materials,” according to FEMA preparedness guidelines.
Residents who felt these earthquakes can report their experiences through the USGS “Did You Feel It?” program to help scientists map shaking intensity patterns.
Current Seismic Status
Seismological agencies continue monitoring these regions. USGS data indicates aftershocks are expected near the Oregon coast following the magnitude 5.8 event.
The current global seismic activity remains near long-term statistical averages, according to seismic monitoring agencies.
The recorded earthquakes in Oregon, California, Greece, and Japan were verified by local geological agencies. All information remains preliminary and subject to revision as additional data becomes available.For the latest earthquake information, USGS maintains real-time monitoring at earthquake.usgs.gov/earthquakes/map/.
