Stress Promotion of the 1958 M_w∼7.8 Fairweather Fault Earthquake and Others in Southeast Alaska by Glacial Isostatic Adjustment and Inter‐earthquake Stress Transfer

Abstract We assess how recent glacial isostatic adjustment (GIA) and inter‐earthquake stress transfer modulated the state of on major faults in Southeast Alaska, these effects may have influenced large moderate earthquakes. The Glacier Bay Icefield has lost >3,000 km 3 ice since ca. 1770, with thinning up to 1.5 km, rest southeast Alaska been deglaciating 1900. resulting GIA response solid earth produces present‐day surface uplift rates ∼4 cm/yr, among fastest Earth. This rapid deformation occurs directly alongside atop Fairweather Fault, which accommodates 4–5 cm/yr right‐lateral motion through slip frequent earthquakes, recently including a M w ∼7.8 earthquake 1958. find that 1958 nucleated very close location maximum GIA‐induced Coulomb increase Fault between 1770 (estimated at ∼0.2–0.6 MPa), only section fault where changes had involved both shearing unclamping. September 10, 1899 ∼8.1 Yakutat also promoted failure least northwest part eventual rupture. In turn, earthquakes along St. Elias compressional margin, site ∼7.4 event 1979. While tectonic loading is likely main driver we estimate 23 30 instrumentally constrained ≥ 5.0 this region were by post‐1770 GIA.