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[1] The similar meander geometries of Venusian canali and terrestrial rivers imply that the in-channel flow regimes may be comparable. This work details meander geometry measurements from ten lowland canali and compares the extensive data set produced to a variety of solar system channels. The meander properties of Venusian canali do not closely match any channel so far observed on the terrestrial planets. However, analysis of the relationship between meander wavelength and radius of channel curvature confirms previous suggestions that the canali were carved by a low (water-like) viscosity fluid. Whether the canali are due to thermal and/or mechanical erosion of the plains by an exotic lava, or have some other genesis, the dominant meander wavelengths of 11 to 77 km require peak fluid discharge rates of up to 6.6 × 106 m3 s−1, an order of magnitude larger than terrestrial rivers. Slight decrease in width along the channel length was observed in most investigated canali, perhaps reflecting the effect of downstream loss processes. Cyclical variations in the average channel width were observed in some channels; where topographic data are available, these variations apparently correlate with peaks in plains topography. This indicates that the canali remained active, after their initially rapid formation, long enough to interact with the early stages of plains tectonism.

[1] High-resolution digital elevation models (DEMs) derived from Magellan Left-Left Stereo synthetic aperture radar data of Venus for a set of impact craters ranging in rim diameter from 5 to 300 km exhibit depths broadly as expected from theory but with significant departures for both large and small craters. In craters larger than 38 km diameter, rim-floor depth becomes independent of diameter with a mean of about 900 m. Most craters smaller than 18 km diameter are also found to be unexpectedly shallow. We discuss the accuracy and principal sources of error in our DEMs and conclude that this shallowness is real. This shallowness of small craters shows that midsize bolides (200–1000 m diameter) fragment in Venus' atmosphere and disperse over an area 10 to 20 times the original bolide diameter. We identify these craters as a new class of impact feature, the Compound Crater, which may correspond to the Knobby Base morphological class defined by others.