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<\/a><\/p>\nThis hemispheric view of Venus was created using radar observations, including images from NASA\u2019s Magellan spacecraft. Magellan imaged more than 98% of Venus. Gaps in the Magellan coverage were filled with images from the Earth-based Arecibo radar. The composite image was processed to improve contrast and to emphasize small features, and was color-coded to represent elevation. Magellan launched on May 4, 1989, and was deployed from the cargo bay of Space Shuttle Atlantis on May 5, 1989. The spacecraft orbited Venus from August 10, 1990, until October 13, 1994 when the spacecraft was commanded to plunge into the atmosphere of Venus. Image credit: NASA \/ JPL-Caltech \/ USGS.<\/p>\n
\u201cRift valleys, which indicate tectonic activity, can be vast and resemble those on Earth, such as the African Rift Valley. On Venus, they can span up to 10,000 km,\u201d said ETH Zurich\u2019s Professor Taras Gerya and colleagues.<\/p>\n
\u201cThe timing of these rifts\u2019 formation is uncertain. Geoscientists believe they originated more than 100 million years ago and are therefore remnants of the past.\u201d<\/p>\n
In the study, the authors used a new computer model to simulate high-resolution, 3D rifts on Venus for the first time.<\/p>\n
This allowed them to accurately replicate rift structures and provide better explanations of their formation.<\/p>\n
\u201cThe models indicate that broad ridges, known as rift flanks, form along the edges of rift valleys when the rifts are geologically young and either still actively moving or have only recently stopped moving,\u201d they said.<\/p>\n
\u201cThe simulations also suggest that these rifts widen more rapidly than had been previously believed, at a rate of 3 to 10 cm per year.\u201d<\/p>\n
\u201cWe also show that the rift flanks tend to flatten rapidly after movement ceases; the older the rift system, the less steep and narrow its flanks.\u201d<\/p>\n
\u201cUnlike Earth, where erosion gradually wears down features, Venus\u2019 flanks subside due to crustal relaxation.\u201d<\/p>\n
\u201cWide and high rift flanks are not only produced by the computer model but can also be seen in images of the Venusian surface from NASA\u2019s Magellan probe during its 1990\u2019s mission.\u201d<\/p>\n
Based on their simulations and observational data, the researchers conclude that Venus remains an active planet with a more dynamic interior than had been previously believed.<\/p>\n
\u201cThe results help us to better assess the tectonic activity on Venus,\u201d Professor Gerya said.<\/p>\n
\u201cThey also could help pinpoint active regions worthy of detailed investigation for the future missions to Venus.\u201d<\/p>\n