  Analysis of pseudorapidity fluctuations in interactions of 10.7 AGeV
$_{79}Au^{197}$ and 158 A GeV $_{82}Pb^{208}$ nuclei with photoemulsion nuclei
by Hurst method, is carried out. As result, events of explosive and mixed
types, are discovered. These types have different fragmentation
characteristics. The most events of the explosive type are processes of full
destruction of projectile nucleus, in which multicharge fragments are absent.
Events with several multicharge fragments of projectile nucleus are processes
of mixed type. Moreover, these two types are separated in multiplicity
distribution. Relative number of events of mixed type for 10.7 Au+Em
interaction is significantly more than for 158 Pb+Em. Quantity of events of
explosive type is approximately equal for both case.
