Cape Verde

Cape Verde is an archipelago of volcanic islands rising from the mid-Atlantic ocean floor, located approximately 500 kilometres west of the coast of Senegal. The islands owe their existence not to plate boundary tectonics but to a mantle hotspot — a column of anomalously hot rock rising from deep within Earth's mantle that has punched through the Atlantic oceanic crust, generating a series of shield volcanoes over millions of years. This volcanic origin means seismicity in Cape Verde is primarily of volcanic and intrusive type rather than the tectonic earthquake variety seen on plate boundaries.

The most seismically and volcanically active island in the archipelago is Fogo, which hosts the Pico do Fogo stratovolcano — one of the most active volcanoes in the Atlantic. Eruptions in 1951, 1994–1995, and most recently in 2014–2015 were each accompanied by swarms of small-to-moderate earthquakes as magma forced its way through the volcanic edifice. The 2014–2015 eruption, which lasted from November 2014 to February 2015, required the evacuation of 1,000 residents from the Cha das Caldeiras caldera and was preceded by a notable increase in [[seismic-wave]] activity detected by local and regional networks.

Historically, the most damaging seismic-volcanic event in Cape Verde was associated with the 1951 Fogo eruption, which also triggered ground cracking and structural damage. The broader island chain experiences occasional tectonic micro-earthquakes along fracture zones in the oceanic crust beneath the archipelago. No large tectonic earthquake analogous to those on plate boundaries has been recorded in the modern era, but the [[magnitude]] of volcanic earthquakes during eruptions has reached 4.5 to 5.0 locally.

Cape Verde's position on oceanic crust formed at the Mid-Atlantic Ridge means the underlying rock is geologically young and relatively thin compared to the ancient cratons of continental Africa. Hotspot magmatism has built thick sequences of basaltic lavas on the seafloor, and the islands themselves represent the exposed caps of these volcanic structures.