Discussion of “Experimental investigation of impact generated tsunami; related to a potential rock slide,Western Norway” by G. Sælevik,A. Jensen,G. Pedersen [Coastal Eng. 56 (2009) 897–906]

This paper is a discussion of Sælevik et al. (2009). Their comparison between block and granular model results is described in more detail, along with a discussion of five parameters which may be in general responsible for deviations between block and granular models. New small scale physical model tests have been performed to support some of the statements made. Finally, it is argued that the use of physical model testing based on simplified geometries are justified in practice and normally produce results that are considerably better than an order of magnitude.