VAN, CANDIDACY AND VALIDATION WITH THE LATEST LAWS OF THE GAME AND PRECURSOR CANDIDACY AND VALIDATION, THE VAN CASE SO FAR - REPLY-II

A simple inspection of the Tables of Mulargia and Gasperini [1992, 199 6a] that refer to the period 1987-1989 reveals the following two facts : (i) by recalling that predictions are issued only when the expected magnitude is M(pred)greater than or equal to 5.0, the true VAN success rate is 79% (for Delta r less than or equal to 120km) while the (inco rrect) success rate of 45% emerges when restricting only correlations that include earthquakes with M(EQ)greater than or equal to 5.0 are co nsidered as successes, and(ii) the VAN alarm rate increases significan tly for larger earthquake magnitudes, i.e., for M(EQ)greater than or e qual to 5.0, 5.3, 5.5 and 5.8, the alarm rates are 22%, 36%, 50% and 6 0% respectively. These facts are inconsistent with their claim that '' VAN results can be ascribed to chance.'' This claim also contradicts t he conclusions obtained from the calculations by Aceves et al. [1996], and by Honkura and Tanaka [1996]. In a separate Section we give answe rs, point by point, to various statements made in the two papers by Mu largia and Gasperini [1996a,b]. Most of these statements are obviously untrue. For example, they claim that ''VAN predictions have been docu mented primarily by circulating telegrams among the members of the VAN -group'' although: (i) the Greek Authorities (as well as 29 Internatio nal Institutes) receive the VAN predictions well before the earthquake occurrence and (ii) it is extensively known that the two most destruc tive activities in Greece during the period 1987-1994 were publicly an nounced by VAN well in advance. Furthermore, Mulargia and Gasperini [1 996a] claim that, for the period 1990-1992, VAN correctly predicted on ly 2 out of 16 EQs with M(s)(=m(b)+0.3)greater than or equal to 5.0; h owever, a check of the VAN data of this period (see Varotsos et al., 1 993c) shows that the alarm rate is 8/20, for EQs with m(b)>4.7, acid i ncreases to 3/4 for EQs with m(b)>5.0.