A magnitude 6.1 earthquake struck 25 kilometers east-northeast of Port-Olry, Vanuatu, at 02:24 UTC on Oct. 25, 2026, which was 1:24 p.m. local time, and the USGS received four felt reports for it. It came 23 hours and 52 minutes after a bigger shock, a magnitude 6.9 on Oct. 24, and the day between them was filled with more than a dozen smaller shocks.
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Vanuatu sits where the Australian plate dives beneath the island arc, and its earthquake catalog is rarely empty. Even so, the stretch from Oct. 24 to Oct. 25 stands out. In the USGS list of earthquakes of magnitude 4.6 or larger worldwide since noon UTC on Oct. 24, 15 of the 34 entries are in the Vanuatu region, and nearly all of those lie to the northwest of Port-Olry, which is the village on Espiritu Santo used as the reference point for most of the entries.
The 6.9 and the 6.3 that followed within five minutes
The largest shock in the sequence was a magnitude 6.9 recorded 197 kilometers west-northwest of Port-Olry at 02:31 UTC on Oct. 24, or 1:31 p.m. in Vanuatu. USGS lists its depth as 10 kilometers, a value that appears on so many entries in this sequence that it should be read as nominal rather than measured. Four people sent felt reports, the agency’s loss-estimation alert is green, and the record carries a tsunami flag with a linked information statement from the National Tsunami Warning Center rather than a warning.
A magnitude 6.3 followed 170 kilometers northwest of Port-Olry at 02:35 UTC, about four and a half minutes later. Together they opened the sequence, and by 08:56 UTC the same day a magnitude 5.9, 196 kilometers northwest of Port-Olry, had joined them.
The moment-tensor solution for the 6.9 describes normal faulting, with a source that lasted about 15 seconds. An early automatic solution had put the magnitude higher, at 7.2, before the reviewed Mww of 6.9 replaced it, which is why this account sticks to the reviewed values posted on each event page. All times in Vanuatu run 11 hours ahead of UTC, so the 6.9 struck in the early afternoon and the 6.1 a day later struck at almost the same hour.
Eleven shocks of 5.3 or larger in three days
A USGS query covering noon UTC on Oct. 23 to noon UTC on Oct. 26, limited to a 400-kilometer radius around Port-Olry, returns 11 earthquakes of magnitude 5.3 or larger. In order of time they are the 6.9 and the 6.3 at about 02:31 and 02:36 UTC on Oct. 24, then a 5.7 at 04:05, a 5.8 at 04:12, a 5.3 at 04:19, a 5.8 at 05:23 and a 5.3 at 06:04, a 5.5 at 06:43 and the 5.9 at 08:56. The last two entries are the 6.1 and a 5.4 on Oct. 25, according to the USGS catalog query.
Nine of those eleven came within the first seven hours after the 6.9, and every one except the 5.5 and the 6.1 is listed at a depth of 10 kilometers, most of them 170 to 205 kilometers from Port-Olry. A second USGS query for the same part of the Pacific, running from Oct. 22 to noon on Oct. 24, found no earthquake of 5.5 or larger before the 6.9, so the sequence opened with its biggest shock rather than building toward it. The 5.5 is the exception, a magnitude 5.5 only 55 kilometers north-northeast of Port-Olry at 194.6 kilometers depth, a deep shock that belongs to a different part of the plate boundary than the shallow cluster in the northwest.
The 6.1: 116 kilometers down and felt close to Port-Olry
The magnitude 6.1 on Oct. 25 is a different kind of event from the cluster that preceded it. It sits only 25 kilometers from Port-Olry, not 170 to 216, and its depth is 116 kilometers, not the nominal 10. The 6.9 and the 6.1 each drew four felt reports, a small count for earthquakes of that size.
USGS rates the felt intensity from those reports at about 4.3 on the Modified Mercalli scale, which corresponds to shaking noticed indoors by many people, and its ShakeMap peaks near the same value. Four responses is a small sample, so that figure rests on a handful of people. The alert is green, the tsunami flag is zero, and the record lists no damage or casualty estimate beyond that green alert.
Later on Oct. 25 the sequence continued with a magnitude 5.4, 205 kilometers northwest of Port-Olry, at 08:41 UTC, or 7:41 p.m. local time. It returned the activity to the shallow cluster in the northwest, where it started.
Reading the list in order, the sequence has two layers. A shallow swarm northwest of Port-Olry produced the 6.9, the 6.3 and most of the aftershocks. Separately, deeper ruptures closer to Espiritu Santo, the 5.5 at 194.6 kilometers and the 6.1 at 116 kilometers, appear on both days. Whether the two are linked is not something the catalog answers, and nothing in the records read for this article says so either way. The practical point for readers following the sequence is to treat each new magnitude on an event page as provisional until it carries the reviewed label that the 6.9, the 6.3 and the 6.1 now hold.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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