In Martinique and Guadeloupe, a strong earthquake (M6.5 to 6.7) was felt on October 27, 2025, at 08:38 (UTC-4): no tsunami alert, aftershocks ongoing. Authorities have activated the COD in Martinique and remind people of safety measures.
What we know: the essentials
An earthquake of magnitude 6.5 according to the USGS and 6.6–6.7 according to the UWI-SRC/OVSM was widely felt on October 27, 2025, in Guadeloupe and Martinique. The main shock occurred at 08:38 (local time, UTC-4), which is 13:38 in Paris. Authorities reported no injuries or major damage at the time of the initial assessments. Several aftershocks followed, including one around 6.0 and another around 5.4.
The epicenter is located at sea, east of La Désirade (Guadeloupe), at a distance between ~160 km and ~220 km from the coasts according to seismological centers. The initial hypocentral depth is estimated at about 10 km.
Magnitudes and location: why the numbers differ
The magnitude of an earthquake is not a single value set in stone. Seismological networks use different methods and catalogs such as moment magnitude, body-wave magnitude, or local magnitude. Thus, these methods can provide slightly different estimates for the same event. Hence, here, a 6.5 from the USGS and a 6.6–6.7 from the UWI-SRC/OVSM.
The same logic applies to location: the exact position of the rupture is calculated via wave propagation models. Moreover, these models use stations distributed across the Lesser Antilles arc. Depending on the network coverage and the geophysical assumptions adopted, the epicenter can be placed ~162 km from La Désirade or ~222 km east of Pointe-à-Pitre. These discrepancies are common in the very first hours and then narrow with reanalyses.
Felt effects and initial measures on the islands
The tremor was clearly perceived in buildings in urban centers and on heights. Additionally, it manifested as oscillations lasting a few seconds. Initial reports mention intensities III–IV (weak to moderate): vibrating objects, preventive exits from buildings, temporary evacuations in several establishments, notably in Fort-de-France. Safety checks were conducted in sensitive facilities (schools, hospitals, infrastructure). No structural damage was confirmed by midday.
In the archipelago, the earthquake was also felt in Dominica, Antigua and Barbuda, or Saint Vincent and the Grenadines. Rescue services reminded people of the guidelines in case of aftershocks. Additionally, they urged not to overload emergency lines unless in a confirmed case.
Tsunami alert: no identified threat
American alert centers indicated no alert, advisory, or tsunami threat. This concerns the Caribbean area. However, information messages circulated in the region while the situation was being verified. This practice is customary after an earthquake felt at sea. In such a context, local authorities apply the precautionary principle. They may request sheltering away from the coast while verifications are conducted.
What science says: a tremor linked to subduction
The event is tectonic. It occurs on the subduction interface where the North American plate sinks beneath the Caribbean plate. This zone, which aligns the Lesser Antilles arc, records regular earthquakes in the Caribbean, sometimes strong.
Observatories remind us of an essential point: no causal link is established between this regional earthquake and the activity of Mount Pelée. Volcanic signals and tectonic signals involve different mechanisms and are analyzed separately.
Earthquakes in the Caribbean: the ordinary of an active zone
Moderate tremors punctuate the news in the Antilles every year. The region has experienced, in the past, much more energetic events. Preparation through municipal plans and the Antilles Earthquake Plan is essential. Moreover, seismic standards compliance plays a crucial role. Finally, risk education remains indispensable. These elements are the major levers to reduce vulnerability to the seismic risk in France (Antilles).
What to do in case of an aftershock? The right reflexes
Aftershocks are possible in the hours and days following a main shock. Here are the life-saving actions:
Indoors: drop, cover, hold on. Stay away from facades, windows, and unstable furniture. Do not use elevators.
Outdoors: move away from walls, poles, signs, and the shoreline. Head to a clear area.
In coastal areas: if the tremor is strong and it’s difficult to stand, react quickly. Similarly, if the sea shows unusual signs like a rapid withdrawal or a rumbling sound, be vigilant. Immediately head to higher ground following local signage, without waiting for instructions.
After the tremor: turn off gas and electricity in case of a leak or suspicious odor. Do not light a flame.
Communications: prioritize SMS and apps to keep emergency lines available. Dial emergency numbers only in case of immediate danger.
Information: follow official accounts of prefectures and observatories. Avoid rumors and unsourced screenshots.
Where to follow validated information (5 useful links)
Networks, prevention, and continuity of services
In this type of event, operational centers record calls and check the state of networks. They ensure the proper functioning of water, electricity, and transportation. Additionally, they coordinate the flow of information from municipalities. Schools and public establishments conduct safety inspections and, if necessary, precautionary evacuations. Local authorities emphasize the importance of simple family plans (rally point, emergency kit, document copies).
On the coastline, caution remains essential in case of a new tremor: staying away from unstable cliffs, respecting barriers in potential collapse zones, and increased vigilance on port structures.
Seismic risk: why this episode matters
This earthquake reminds us that a territory’s vulnerability is not limited to the intensity of a tremor. It depends on the quality of the buildings and the preparation of households. Furthermore, the training of public and private actors is crucial. Finally, the speed of network restoration is essential.
The post-earthquake period is conducive to reminders. Securing tall furniture and checking the anchors of water heaters are essential. Additionally, identifying safe zones at home and work is crucial. Finally, updating evacuation plans is necessary. Companies will benefit from reviewing their business continuity plans and testing their procedures (on-call duty, backups, telecommuting).
To follow
Instrumental data (magnitude, position, depth) may be revised in the coming hours and days, as analyses and cross-checks between networks progress. Authorities promise to communicate in case of a significant development.
Key message: a strong earthquake, but no reported damage, which underscores the need for preparation and the discipline of good reflexes. Staying informed through official channels is essential. Additionally, applying guidelines in case of an aftershock is crucial. Finally, checking the buildings daily remains one of the best shields against seismic risk in the Lesser Antilles.