Geodynamics and Regularities of Seismicity in the Eastern Segment of the Amurian Plate

Research reveals that seismic activity in the southeastern part of Far Eastern Russia is driven by strain waves nucleating at the buffer zone of the northeastward-moving Amurian Plate. The study identifies a high-seismicity zone (M ≥ 4.5) in Lower Priamurye, linked to reactivation of the Bureya Orogen, where regional compression peaks beneath a meridional dome with increased Moho depth (36–40 km). A negative gravity anomaly marks lower rock density in this orogen, while contemporary uplift has triggered centrifugal migration of strong earthquakes (M ≥ 5.0) from the dome's center to its periphery between 1983 and 2009. Additionally, seismicity south of the Bureya Orogen is concentrated along the Tan-Lu Fault zone, where northeastward-migrating foci result from tangential rotation of the Amurian Plate, pushing the Central Sikhote-Alin block southward. This tectonic interaction also influences deep-focus earthquakes (M ≥ 6.0) at depths of 400–600 km in the Pacific Plate's subduction zone.

Stepashko, A. A., Merkulova, T. V., & Didenko, A. N. (2018). Geodynamics and Regularities of Seismicity in the Eastern Segment of the Amurian Plate. Russian Journal of Pacific Geology, 12(4), 263–277. https://doi.org/10.1134/s1819714018040061