Seismologists have recorded a magnitude 4.5 earthquake in the Pacific region, with the epicentre located 275 km E of Levuka, Fiji. The event occurred at 19:42 UTC on Thursday, July 23, 2026 and originated at a depth of 541.6 km.
Seismic Context for the Pacific region
The Pacific Ocean basin is ringed by the world's most active subduction zones, collectively known as the Ring of Fire. This region produces approximately 90% of the world's earthquakes and the great majority of its major tsunamis.
Pacific island nations face unique challenges: small land areas, limited evacuation options, and direct exposure to both strong shaking and tsunami inundation. The Pacific Tsunami Warning Center (PTWC) in Honolulu monitors the entire Pacific basin and issues alerts to member nations.
About This Event
At a focal depth of 541.6 km, this is a deep earthquake (below 300 km), occurring well within Earth's mantle. Deep earthquakes are a distinctive feature of subduction zones where cold oceanic crust descends into the mantle. Despite the large magnitude, the extreme depth means surface shaking is distributed over a vast area and is considerably less intense at any single point than a shallow event of equivalent magnitude.
In terms of felt effects, a magnitude 4.5 earthquake is typically felt strongly by everyone; minor to moderate damage possible in vulnerable buildings. Moderate earthquakes are felt by virtually everyone near the epicentre. Strong shaking lasting 10–30 seconds can topple unsecured items, crack plaster, and cause poorly anchored objects to fall. Aftershocks are common following moderate events.
Understanding the Magnitude Scale
Earthquake magnitude is measured on a logarithmic scale — meaning each whole-number increase corresponds to roughly 32 times more energy released and approximately 10 times greater ground motion amplitude. A magnitude 4.5 event therefore releases significantly more energy than its number alone might suggest to the casual observer.
A magnitude 4.5 earthquake releases approximately roughly 500 tonnes of TNT of energy. For comparison, this exceeds the energy released by most conventional explosive events and is sufficient to shift tectonic stress in measurable ways across a wide region.
Significant damage can occur to vulnerable structures — particularly unreinforced masonry, old adobe buildings, and poorly maintained older construction. Well-engineered modern buildings are designed to withstand this level of shaking with minimal structural impact, though contents may shift and non-structural elements (ceilings, partitions) can be damaged.
What to Do After an Earthquake
Agree on an out-of-area contact that family members can reach if local communications are disrupted. Identify two meeting points: one near your home and one further away. Practise earthquake drills, especially with children and elderly household members.
If you are on or near a coast and experience strong or prolonged earthquake shaking, treat it as a potential tsunami warning and move immediately to high ground. Do not wait for an official alert — natural warning signs (severe shaking, unusual sea withdrawal) are your first alert.
Staying Informed
Coastal communities throughout the Pacific should treat any strong earthquake as a potential tsunami warning and move inland or to elevated ground without waiting for an official alert.
QuakeWatch publishes real-time earthquake data sourced from the USGS global catalog — covering every detected seismic event worldwide, 24 hours a day. Visit our live map to see this and all other recent earthquakes, or explore our guide to earthquake magnitude for a deeper understanding of what these numbers mean in practice.
The Science of Seismic Monitoring
Modern earthquake detection relies on a global network of seismographs — sensitive instruments that record ground motion in all three dimensions. When an earthquake occurs, the P-waves (primary, compressional waves) arrive first, followed by the slower S-waves (secondary, shear waves), and finally the surface waves that cause the most felt shaking. By comparing arrival times at multiple stations, scientists can triangulate the earthquake's location and calculate its magnitude within minutes of the event.
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