Experts: Three powerful earthquakes in California, Japan, and Venezuela struck in the same eight-hour window but were not connected

A 5.6-magnitude earthquake struck a rural area of northern California on Wednesday, and hours later, a 7.2-magnitude earthquake hit the northern coast of Japan. Within the same eight-hour window, two powerful earthquakes rocked Venezuela, according to reports that raised concerns about whether separate disasters were linked. Scientists and seismologists cited by The Guardian said the events were not related.

The California quake, described as affecting a sparsely populated part of the region, occurred before the Japan event. The timing then shifted to the Pacific and Asia, where the 7.2-magnitude earthquake was reported hours after the U.S. tremor. The Japan quake was characterized as powerful enough to draw international attention because of its magnitude and proximity to the northern coastline.

After the Japan earthquake, additional large earthquakes were reported in Venezuela. The Guardian said two major quakes in the South American country occurred during the same overall span of time, making the cluster of events noticeable to the public even though seismologists do not view them as a single system.

Experts interviewed for the report said the closeness in time does not mean a shared source. Earthquakes are caused by stress changes along faults in different tectonic settings, and multiple major quakes can occur worldwide within hours due to the natural randomness of when faults reach critical stress.

Seismology researchers also noted that oceanic and continental fault systems are separate, and that even large tremors do not necessarily trigger other earthquakes at distant locations in a way that creates a direct chain reaction. While aftershocks can follow a major quake in the same area, linking different countries’ earthquakes requires specific evidence of a trigger mechanism, which experts said was not present in this instance.

Local authorities typically treat each quake as its own emergency, focusing on immediate public safety measures such as assessing damage, monitoring ongoing aftershocks, and checking infrastructure. The report said the simultaneous international attention stemmed from the combination of high magnitudes and the short time interval, rather than from evidence of a single geophysical event spanning regions.

In the coming days, the focus is expected to remain on confirmatory assessments, including official magnitude estimates, epicenter locations, and early damage and casualty accounting in each country. Officials and scientists will also refine aftershock monitoring, which is usually concentrated around each earthquake’s fault region rather than across unrelated tectonic systems.