LAVA SU VENEREPUBLIC INFORMATION OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011 PHOTO CAPTION
A portion of the eastern edge of Alpha Regio is displayed inthis three-dimensional perspective view of the surface of Venus.The viewpoint is located at approximately 30 degrees southlatitude, 11.8 degrees east longitude at an elevation of 2.4kilometers (3.8 miles). The view is to the northeast at thecenter of an area containing seven circular dome-like hills. Theaverage diameter of the hills is 25 kilometers (15 miles) withmaximum heights of 750 meters (2,475 feet). Three of the hillsare visible in the center of the image. Fractures on thesurrounding plains are both older and younger than the domes. Thehills may be the result of viscous or thick eruptions of lavacoming from a vent on the relatively level ground, allowing thelava to flow in an even lateral pattern. The concentric andradial fracture patterns on their surfaces suggests that achilled outer layer formed, then further intrusion in theinterior stretched the surface. An alternative interpretation isthat domes are the result of shallow intrusions of molten lava causing the surface to rise. If they are intrusive, then magmawithdrawal near the end of the eruptions produced the fractures.The bright margins possibly indicate the presence of rock debrisor talus at the slopes of the domes. Resolution of the Magellandata is about 120 meters (400 feet). Magellan's syntheticaperture radar is combined with radar altimetry to develop athree-dimensional map of the surface. A perspective view is thengenerated from the map.Simulated color and a process calledradar-clinometry are used to enhance small-scale structures. Thesimulated hues are based on color images recorded by the SovietVenera 13 and 14 spacecraft. The image was produced by the JPLMultimission Image Processing Laboratory by Eric De Jong, Jeff Hall, Myche McAuley, and Randy Kirk of the United StatesGeological Survey, and is a single framefrom the movie releasedat the May 29, 1991 Magellan news conference.