My thesis is the one sempaiscuba♦ suggested. Your question is far more complex than one might think on first glance. In the short, it varies from place to place and it depends on where the crime was committed.
First, one must understand that the raping and pillaging actions of the Vikings were commonplace in most areas and of most people in Europe, especially during wartime, but the Vikings became particularly noticeable because they were not Christians and Christians provide most of the non-Viking sources of Viking behavior. It is like the enemy writing the history of a defeated foe, while conveniently disregarding their own actions.
Second, one must understand that raiding was part of Viking culture which developed out of scarce resources. Lack of primary sector industrial goods, such as ores, wood, and food stuff made pillaging a good way to get necessary goods and create wealth.
Within the context of this understanding, sexual misconduct in any fashion within Iceland had direct repercussions to the instigator, and occasionally the victim, by means of outlawry. Outside Iceland, the laws of those lands dictated the repercussions, though it is widely believed that Icelandic law was a modified version of Norwegian law so anywhere that spoke Norse had some basis in those laws. For example, in the English Danelaw, it is likely the people living there were subject to laws similar to Icelandic lawsbecause they were developed out of Norwegian ones, with a bit of Anglo-Saxon law to keep the peace with the Anglo-Saxon rulers of the what is today southern England. The same is likely true of the Shetlands and much of Scotland.
Normandy was subject to French authority so it would have followed French law, but only if the perpetrator was caught. Oftentimes, they were not due to their ability to raid quickly and move on before reinforcements could arrive. Beyond that, the Vikings traveled all over Europe and it is difficult to say with any certainty what the laws in those places where because there are few, if any, written sources. This is especially true of eastern Europe.
I hope this helps!