Great Rift Valley Great Rift Valley The Great Rift Valley is a continuous geographic trench, approximately in length, that runs from Lebanon's Beqaa Valley in Asia to Mozambique in Southeastern Africa. The name continues in some usages, although it is today considered geologically imprecise as it combines features that are today regarded as separate, although related, rift and fault systems. Today, the term is most often used to refer to the valley of the East African Rift, the divergent plate boundary which extends from the Afar Triple Junction southward across eastern Africa, and is in the process of splitting the African Plate into
Volcanic history of the Northern Cordilleran Volcanic Province dated or have not been dated in significant detail to identify more individual temporal patterns. Lava fountains can occur in the Northern Cordilleran Volcanic Province roughly every 100 years. Large basaltic shield volcanoes throughout the central Northern Cordilleran Volcanic Province form large lava plateaus and are the largest volcanoes of the volcanic zone. These extensive volcanoes are generally larger and more long-lived than volcanoes of adjacent volcanic zones, including the stratovolcanoes of the Cascade and Aleutian arcs. Mount Shasta, the largest stratovolcano in the Cascade Arc and Mount Veniaminof, one of the largest and most active volcanoes in the Aleutian