The southwestern portion of the Arabian Plate lies adjacent to the Afar Triple Junction (an area of spreading ridges) near the Red Sea. The triple junction marks the intersecting point of the Arabian, African, and Somali plates. Spreading initiated around 5 mya and persists at 6-7.5 mm per year in the southern Red Sea and ~10 mm per year in the eastern Gulf of Aden. Earthquake activity is normally focused at the undersea ridges, but infrequent small to moderate events occur on land in the interior of the Arabian plate within of the centerline of the Red Sea in Yemen, as well as farther to the northwest in the 'Asir Region of Saudi Arabia.