The 2007 Martinique Earthquake and Regional Seismicity

Martinique lies within the Lesser Antilles volcanic arc, where the North American plate subducts westward beneath the Caribbean plate at roughly 2 cm per year. This convergent margin produces both arc volcanism, exemplified by Mount Pelée, and a Wadati-Benioff zone that extends to depths exceeding 150 km. Intermediate-depth earthquakes commonly occur within the subducting slab as it descends and dehydrates. On 29 November 2007 at 19:00 UTC, a magnitude 7.4 earthquake struck 18 km west-northwest of Basse-Pointe at a focal depth of 156 km. The event originated inside the subducting Atlantic slab, consistent with the regional pattern of intraslab seismicity. Because of its depth, peak ground accelerations remained modest across the island, and damage was limited primarily to minor structural cracking and landslides in steep volcanic terrain. Since 1 January 2000, this earthquake stands as the only magnitude 7.0 or greater event recorded within 100 km of Martinique. Earlier historic shocks, such as the 1839 event estimated near magnitude 7.5, demonstrate that large earthquakes have repeatedly affected the island, yet none have matched the 2007 depth and size in the modern instrumental era. The subduction interface and its associated slab geometry continue to control seismic hazard. Ongoing GPS measurements indicate ongoing plate convergence, while volcanic monitoring networks track both magmatic and tectonic signals. Future events at intermediate depths remain possible and underscore the value of preparedness even when surface shaking is attenuated by depth.

References

USGS Earthquake Catalog (event page for 2007-11-29 M7.4 Martinique) Global CMT catalog Caribbean Tsunami Information Center historical reports