The NASA Magellan spacecraft provided synthetic aperture radar (SAR) image coverage of 98% of the surface of the planet Venus, in addition to topography and several types of physical property data on the venusian surface (e.g., radar reflectivity, radar backscatter, emissivity, and rms slopes).(See Special Magellan Issue of J. Geophys. Res., v. 97, nos. E8 and E10, August 25 and Sept. 25, 1992.) This Open-File Report contains a listing (table 1) of impact craters based on interpretation of the Magellan data, and was compiled with the official sanction of the Magellan Science Team (Steve Saunders, Magellan Project Scientist, personal communication, 1990). This crater data base has been revised, updated, and expanded from those used by the authors in earlier publications (Schaber and others, 1992; Strom and others, 1994).
The database tables include the name (where applied), coordinates, diameter, modification state, crater morphologic type, and mean elevation of 967 craters interpreted to be of impact origin within the area of the planet imaged by the Magellan spacecraft between 1990 and 1994. For more details on interpretations of the Venus impact cratering record, the reader is referred to Campbell and others, 1992, Phillips and others (1991, 1992), Schaber and others (1992), Chadwick and Schaber (1993), Alexopoulos and McKinnon (1994), Herrick (1994), Herrick and Phillips (1994), Nakimi and Solomon (1994), Price and Suppe (1994), Strom and others (1994), Price and others (1996), Herrick and others (1995), and Strom and others (1995).
An alternate Venus impact crater data base that includes additional information on crater morphology has been described by Herrick and Phillips (1994). An excellent source for the current thinking about impact craters on Venus and their implications can be found in the University of Arizona Press book, Venus II (Bougher and others - Editors, 1997). Relevant Chapters on impact cratering in the Venus II book were contributed by Basilevsky and others (1997), Herrick and others (1997), and McKinnon and others (1997).
Numerous impact craters >15 km in diameter on Venus have been named for famous women (last names). Some smaller impact craters <15 km in diameter have been given common female first names from various ethnic groups. During Summer 1997 the IAU Committee on Planetary Nomenclature approved the suggestion that first names of females from various ethnic groups be assigned to impact craters with diameters down to 5 km. As a result, the IAU Committee during 1997 approved a total of 323 new Venus crater names. These newly approved names can now be referenced in the literature and have been included in the revised U.S. Geological Survey/University of Arizona Venus impact crater data base shown in the tables. The reader is referred to the Gazetteer of Venusian Nomenclature (Russell, 1994) and to the Gazetteer of Planetary Nomenclature for name origins and the use of the proper diacritics (not indicated in table 1).
Larger versions of most sample images are available by selecting either the modification state image or crater name. The size of the larger image is given in kilobytes (kb). Large images are all at a scale of 225 m/pixel. The images retain the rull radiometric calibration (Pettengill and others. 1991).
Note: The modification state of the impact craters on the database is subject to individual interpretation and bias of the authors. Note also that many craters on the database have been assigned modification state designations that are a combination of two or maore of the individual sumbols shown below. For example. the crater heloise designated vhp1 in the database represents a slightly fractured crater (f1) which has been heavily embayed by volcanic lava plains (vh) durning the last global resurfacing event (p).
Note: The symbol p used alone in the modification state column of the table always represents a pristine (essentially unaltered) crater. Howerver, when p is used in combination with other symbols in the Modification State column, it never means pristine. Here, it symbolizes (in abbreviated form) a lava-embayed crater that is interpreted to have been embayed by lava plains deposits during the last global resurfacing episode - not subsequent to it.
Examples of the basic states of impact crater modification used are:
Larger versions of most sample images are available by selecting either the modification class, the thumbnail image or crater name. The size of the larger image is given in kilobytes (kb). Large images are all at a scale of 225 m/pixel. They have not been stretched to enhance contrast, but retain the full radiometric calibration Pettengill and others, 1991.
The types of crater morphologies listed on the data base are as follows:
The mean elevation values given are derived from the Magellan radar altimetry( Pettengill and others, 1991; Ford and Pettengill, 1992) and represent the pre-impact surface, assuming no tectonic deformation. The mean elevation included in the data base was determined from root 3 and 2 crater radii--outside the range of the average hummocky and radial crater rim deposits (but not the bright crater outflow deposits) (see Kirk and others, 1995). Mean elevation values based on Magellan altimetry data have a vertical accuracy from 80 m to 200 m (Ford and Pettengill, 1992).
