Small graben, narrow linear troughs, have been found associated with small scarps (lower white arrows) on Mercury, and on the Moon. The small graben, only tens of meters wide (inset box and upper white arrows), likely resulted from the bending of the crust as it was uplift in response to scarp formation. On the basis of the rate of degradation and infilling of small troughs on the Moon by continuous meteoroid bombardment, small lunar graben and their associated scarps are less than 50 Myr old. It is likely that Mercury’s small graben and their associated scarps are younger still, because the cratering rate on Mercury is a factor of 3 greater than on the Moon.
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington/Smithsonian Institution
