Relation between your 'Keywords' and 'AdSense' earning;

Is it possible to earn better from Google Adsense only depending on your social and referral traffic? 

I think NO. Because Adsense itself is a contextual advertising program which mean it preforms better for search engine traffics.

Now- Google Adsense also reads browser cookies and serves interested based ads to your users, withal it is contextual first. Advertisers also target keywords when they place their ads on AdWords. So, here is no doubt that Adsense will perform better for search traffic. 

Here is also an another reason- that search traffics have always had an intention to search something on your website or blog.

So, Your Adsense earning will not only depend on your ad placement but also it depend on your keywords. If you want to better performance from Adsense then you have to focus on your keyword selection and its usages on your websites or blogs.