Regularities of Manifestation of Active Faults and Seismicity in the Southern Part of the Siberian Craton

摘要

Despite increased interest in the problems of modern activation of the marginal parts of ancient cratons in the last decade, seismicity and active faults in the Siberian Craton have not been studied well enough. Only a few publications are known that are dedicated mainly to the southern part of the craton: the Irkutsk Amphitheater bordering the Sayany-Baikal mobile belt. Golenetskii [1,2], who classified the study region as an area with specific moderate (K_p ≤ 11) seismicity, did not find any correlation between individual earthquakes or their clusters and the tectonic structure of the craton (fractures included). Later, active (in the last 100-130 ka) fractures were distinguished in some regions of the Irkutsk Amphitheater [3-9 and others]. Some of them [5] were classified as fractures produced by sufficiently strong earthquakes (M = 6.5). However, the general concepts about the interaction between large blocks over wide zones of increased dislocations and the existence of close spatiotemporal correlations between tectonic activity in cratons with similar processes in the boundary mobile belts [10-12, and others], spreading of modern anomalously high formation pressures and layer-by-layer disruptions in the central part of the Irkutsk Amphitheater [13], and the relation of the entire territory to the Baikal Rift transition zone [14] evidence that the process of intense fracturing should cover the craton to a greater degree than was revealed by the previous investigators.