photography - How tall are the "fractured" linear structures on Europa's surface?

What are the altitude differences in the high resolution part of this image of Europa?

How high do those ridges rise over their neighboring valleys? And how large is the area shown in this image?

And are the craters believed to have been formed by impacts or some kind of "eruptions" from below? It looks to me as if the areas which have the most (tiny) craters is on top of and thus newer than the less cratered areas. Well, here and there anyway.