  Using three-year moving averages of the complete Journal Citation Reports
1994-2016 of the Science Citation Index and the Social Sciences Citation Index
(combined), we analyze links between citing and cited journals in terms of (1)
whether discontinuities among the networks of consecutive years have occurred;
(2) are these discontinuities relatively isolated or networked? (3) Can these
discontinuities be used as indicators of novelty, change, and innovation in the
sciences? We examine each of the N2 links among the N journals across the
years. We find power-laws for the top 10,000 instances of change, which we
suggest interpreting in terms of "self-organized criticality": co-evolutions of
avalanches in aggregated citation relations and meta-stable states in the
knowledge base can be expected to drive the sciences towards the edges of
chaos. The flux of journal-journal citations in new manuscripts may generate an
avalanche in the meta-stable networks, but one can expect the effects to remain
local (for example, within a specialty). The avalanches can be of any size;
they reorient the relevant citation environments by inducing a rewrite of
history in the affected partitions.
