16 September 1994
Vol 265, Issue 5179

About The Cover

Shaded topography of the 12-kilometer-long Asal rift (Djibouti, East Africa). Colors indicate elevations, from −150 meters below (dark blue) to 350 meters above (purple) sea level. The topography results from the tectonic dismemberment over the past 100,000 years of a large central volcano (Fieale) that formed astride the rift zone 300,000 to 100,000 years ago. Reconstruction of this volcano indicates a spreading rate across the rift of 17 to 29 millimeters per year. See page 1677. [Image: J.-B. De Chabalier and J.-P. Avouac]