Somalia

Somalia straddles a major tectonic boundary — the diffuse zone of deformation between the Nubian plate to the west and the Somalian plate to the east, which are slowly separating along the East African Rift System. The Gulf of Aden spreading centre forms Somalia's northern coast, and this active spreading ridge generates frequent moderate earthquakes that are felt along the Somali coast and in Djibouti. The East African Rift, which separates the Somalian plate from the Nubian plate, runs through Ethiopia to the west but its stress field influences the broad region.

The Gulf of Aden is an active oceanic spreading centre — a young ocean that has been opening since approximately 25 million years ago. The spreading axis is offset by numerous transform [[fault]]s that run perpendicular to the coast, and these transform faults are associated with the most intense seismicity in the northern Somali region. A major earthquake struck the Gulf of Aden in October 2008 with a [[magnitude]] of 5.9, causing felt shaking in Djibouti, northeastern Ethiopia, and the Somali coast. Several moderate events in the magnitude 5 to 6 range occur annually along the Gulf of Aden spreading system.

The central and southern parts of Somalia, which sit on the Somalian plate interior, experience lower seismicity. The Jubba and Shabelle river valleys cross relatively stable Precambrian and Mesozoic geological terrain. However, the Hargeisa area in Somaliland (northwestern Somalia) has experienced occasional low-magnitude earthquakes, and a magnitude 5.5 event in 2013 near the Berbera coast was widely felt. The Ogaden basin in the south-central region contains ancient rift structures from Mesozoic rifting that can occasionally be reactivated.

The [[seismic-wave]] characteristics of Somali region earthquakes include both normal-faulting events on the Gulf of Aden spreading ridge and strike-slip events on the transform faults. The depth of seismicity varies from very shallow events (< 10 km) on the spreading segments to slightly deeper events (15–25 km) on the transforms. Somalia's lack of continuous seismic monitoring infrastructure — a consequence of the prolonged civil conflict since 1991 — means that the seismic catalogue for the country is incomplete, particularly for the interior regions.