Hello, Ahlam - it wouldn't be a case study as such, unless you were planning on undertaking a comparative study of the same trope with other authors. Having said that, there's absolutely nothing wrong with undertaking a literary interrogation in either of two ways - either an exploration of this particular author's use of such techniques, or a more comparative investigation in the identification of the use of cultural memory/trauma in a range of authors. It depends on the goal of your research topic and the questions you are trying to answer.
I think you would find the following book of readings helpful: Charles S. Ragin and Howard S. Becker (eds.) (1992). What is a Case?: Exploring the Foundations of Social Inquiry. Cambridge University Press. ISBN 0-521-42188-8. The introduction to the volume was written by Charles Ragin. It is entitled "Introduction: Cases of "What is a case?" This seems particularly pertinent (pp. 1-17). Good luck, Bruce
You can do anything, and indeed call it anything you want. However, as you go about doing the kind of research you want to do, you must realize (and convey to your readers) those aspects of your research which correspong with existing methods, and the manners in whic h you diverge from these preconceived methods. Find your way to investigate what you are interested in, and explain why your method of choice is good for this kind of investigation, as well as why it is lacking or what are the disadvatages. In the end of the day you are better off drawing from existing methods than administering them to the letter. There is no method which is perfectly designed for all the cases it aspires to be suitable for. Thus, yes, you may use a case study framework for your study. However, you musthighlight the manner in which your study differs from what may be "case study research propper" (if there is such a thing).
I would recommend a content analysis. She the following publication for an intro to the method http://qhr.sagepub.com/content/15/9/1277.short?rss=1&ssource=mfr
Within Social inquiry models, there is certainly room for the use of modification to existing methods however, as a first exploration (for novice researchers or experienced researchers delving into a new field) it is always best to use an established protocol and follow it strictly. Subsequent discussion can then include rationals for modification to the existing method as you discover "what worked" and "what did not". I feel that the project you mention above is not in the strict sense a case study... perhaps it leans more toward a focused study of cultural perception?