A magnitude 5.4 earthquake shook central Colombia near Rioblanco at a shallow 10 km

A magnitude 5.4 earthquake struck central Colombia at 09:13 UTC on November 3, which was 4:13 a.m. local time, about 24 km north-northwest of Rioblanco in the Tolima department. The U.S. Geological Survey placed the focus at a shallow 10 km. It was the strongest quake in the global catalog for the window that opened the previous afternoon.

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Shaking arrived in the dark hours before dawn, and the agency’s community reporting system had collected 129 felt reports on the event. Colombia’s national geological service, which runs its own seismic network, published a different set of numbers for the same rupture, and the gap between the two catalogs is a useful part of the picture. The agency records carry no casualty or damage figures.

The USGS event page for the quake lists the solution as moment magnitude (Mww) 5.4 at 10 km depth, with a significance score of 511 and no tsunami flag. The agency’s worldwide feed of quakes at magnitude 4.5 and above shows the Colombian shock heading the list of everything recorded since 17:00 UTC on November 2. The next strongest entries were a 5.2 in the Volcano Islands region of Japan, a second 5.2 on the Mid-Indian Ridge and a third 5.2 roughly 91 km east-southeast of Kyzyl-Eshme in Kyrgyzstan.

Mww 5.4 at 10 km in the USGS solution

Moment magnitude is the scale seismologists prefer for quakes of this size because it tracks the total energy released across the fault rather than the peak wiggle at one station, and the “w” suffix marks a solution built from long-period waveforms. A 5.4 sits in the moderate class: strong enough to be felt across a wide area of mountainous terrain, small enough that well-built structures usually come through intact.

The depth deserves a caveat. Ten kilometers is a round number, and global catalogs often carry shallow depths with an uncertainty of several kilometers. The feed entry does not say whether the 10 km figure was computed from the waveforms or assigned as a default, so the safe reading is a crustal quake in the upper part of the Andean plate boundary zone rather than a deep intraslab event.

The significance score of 511 folds magnitude, reported intensity and estimated impact into one number, and values in the low 500s are typical for a quake of this size that struck a populated but not densely built area. For comparison, the three 5.2 events that followed it in the feed carried lower magnitudes and, being offshore or remote, generally lower impact estimates.

Colombia’s own network reads it at 5.6 near Chaparral

The Servicio Geologico Colombiano posts a rolling five-day summary feed, and its closest match is event SGC2026vqkoca: magnitude 5.6 on the local scale (MLr), origin 09:13 UTC, depth 19 km, labeled Chaparral, Tolima. The feed lists Roncesvalles and San Antonio about 17 km from the epicenter and Chaparral about 22 km away. It reports an intensity of 7 on the Mercalli scale and zero felt reports, a field that likely reflects a separate submission system rather than an absence of shaking.

Both agencies agree on the minute, the department and the pre-dawn hour. They differ by 0.2 magnitude units and 9 km of depth. That spread is ordinary. Regional networks with dense local stations often use a local magnitude scale tuned to their own crust, while the USGS publishes a global moment-magnitude estimate from teleseismic data. Neither number is wrong; each answers a slightly different question, and revisions in the first days after an event are common.

Green PAGER alert, 129 reports and a community intensity of 4.8

The USGS PAGER system provides fatality and economic loss estimates after significant earthquakes worldwide, and it scored this event green, the lowest of its color tiers. A green flag means analysts expect little or no damage-driven loss, which fits a moderate quake in a region of small towns and farmland.

Citizen reports tell a similar story. The USGS citizen-science felt-report project gathers accounts from people who felt a quake and turns them into intensity maps. For this event the community intensity came out at 4.8 from 129 responses, while the instrument-based model put the strongest shaking near 6.3 on the Mercalli scale. A modeled peak above the reported average is common in thinly populated mountain terrain, where the strongest shaking falls on slopes with few observers.

Gaps in the early records

Several things are still missing from the public record. Neither agency’s entry carries an aftershock count, a fault-plane mechanism summary or a municipal damage assessment, and local authorities in Tolima had not issued figures that appear in the feeds. Colombia sits where the Nazca plate dives beneath South America, and the Andean interior also hosts shallow crustal faults, so moderate shocks of this kind are routine and most pass without harm.

The time window matters for the “strongest of the day” claim. The USGS feed was queried from 17:00 UTC on November 2, so it covers roughly a day and a half of global seismicity at magnitude 4.5 and above. Within that span only twelve events appear in the list, and none of the others reached 5.3, which makes the Tolima quake the clear leader in the USGS catalog even though a 5.4 is modest by planetary standards. Until the Colombian service publishes a reviewed solution, the 5.4 at 10 km from the USGS and the 5.6 at 19 km from the national network stand as the two readings on record, with 129 felt reports and a green alert as the only impact measures available.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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