Ground deformation near Gada 'Ale Volcano, Afar, observed by Radar Interferometry

Radar interferometric measurements of ground-surface displacement using ERS data show a change in radar range, corresponding to up to 12 cm of subside nce near Gada 'Ale volcano in northern Afar, Ethiopia, that occurred betwee n June 1993 and May 1996. This is the area of lowest topography within the Danakil Depression (-126 m). Geodetic inverse modeling and geological evide nce suggest a volcanic origin of the observed deformation; it was probably caused by a combined process of magma withdrawal from a larger reservoir an d normal faulting. There is no evidence of subaerial eruption. This is the only identifiable deformation event during June 1993-October 1997 in the 80 km long Erta 'Ale volcanic range, indicating surprising inactivity elsewhe re in the range.