Fig. 2. Wave type classification based on the criteria in Table 1: wave type product T¼S1/3M cos[(6/7)a] and (–) Eq. (1) (¼instead of o) and (–) Eq. (3) (¼instead of 4) for (a) present study and (b) data from previous studies (Fritz, 2002; Zweifel, 2004).