Channel avulsions on river deltas are the primary means to distribute sediment and build land at the coastline. Many studies have detailed how avulsions generate delta lobes, whereby multiple lobes amalgamate to form a fan-shaped deposit. Physical experiments demonstrated that a condition of sediment transport equilibrium can develop on the topset, characterized by neither deposition nor erosion of sediment, and material is dispersed to the foreset. This alluvial grade condition assumes steady subsidence and uniform basin depth. In nature, however, alluvial grade is disrupted by variable subsidence, and progradation of lobes into basins with variable depth: conditions that are prevalent for tectonically active margins. We explore sediment dispersal and deposition patterns across scales using measurements of delta and basin morphology compiled from field surveys and remote sensing, collected over 150 years, from the Selenga Delta (Baikal Rift Zone), Russia. Tectonic subsidence events, associated with earthquakes on normal faults crossing the delta, displace portions of the topset several meters below mean lake level. This allogenic process increases regional river gradient and triggers lobe-switching avulsions. The timescale for these episodes is shorter than the predicted autogenic lobe avulsion timescale. During quiescent periods between subsidence events, channel-scale avulsions occur relatively frequently because of in-channel sediment aggradation, dispersing sediment to regional lows of the delta. The hierarchical avulsion processes, arise for the Selenga Delta, preserves discrete stratal packages that contain predominately deep channels. Exploring the interplay between discrete subsidence and sediment accumulation patterns will improve interpretations of stratigraphy from active margins and basin models.