When we get a look at Ceres in 2015 we can get a better ide of of common these grooved surfaces are.
Wow! I had not seen that photo until now. I remember that this body had a goodly impact crater, but the striations were not apparent IIRC.
Although the striations in the case of Phobos could be attributed to the big impact, I don’t think so, as some of the apparent ejecta (or is it CO2 ice?) shades the elevations. This would indicate that the striations pre-date the impact.
We need to go and look.
It’s probably not a coinky-dinky that the lines appear to run off that large impact crater. Whatever struck was apparently shattered by the impact, and some of its larger fragments rolled and ripped the full length of Vesta.