This is an image of the surface of Europa.
Click on image for full size
NASA
Europa Ice Flows
This is an example of terrain of Europa which has been flooded by fresh water which subsequently re-froze on the surface. The edges of the flow are "lobate" meaning rounded like a puddle of water.
This is evidence of icy-volcanism. The water of Europa may have flowed out of the ground the way lava flows out of a volcano on Earth.
Clearly, as shown in the image, the flowing water covered over some ridges on the surface which were already in place.
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