Source: Journal of Geophysical Research: Solid Earth
Between 1938 and 1965, five megathrust earthquakes ruptured the Aleutian-Alaska subduction plate boundary over a length of 3,548 kilometers. Tape and Lomax  revisit these earthquakes, first studied in detail by Sykes , through probabilistic relocation of Mw ≥ 7.7 megathrust earthquakes and their aftershocks. The relocated catalog of 324 events is then used to map the aftershock region of each megathrust earthquake, which reveals the extent of the coseismic rupture.
These aftershock zones differ from previous studies in subtle but significant ways. Several aftershock regions are larger than previously indicated, specifically 1938 and 1964. These results enable a better understanding of how slip occurs along the Aleutian-Alaska subduction zone, either coseismically during earthquake rupture or aseismically by slow slip. The conclusion that aftershock zones of megathrust earthquakes can overlap also has implications for seismic hazard analysis.
Citation: Tape, C., & Lomax, A. (2022). Aftershock regions of Aleutian-Alaska megathrust earthquakes, 1938–2021. Journal of Geophysical Research: Solid Earth, 127, e2022JB024336. https://doi.org/10.1029/2022JB024336
—Agnes Helmstetter, Associate Editor, Journal of Geophysical Research: Solid Earth