Contemporary Fault Mechanics in Southern Alaska

摘要: Thin-shell finite-element models, constrained by a limited set of geologic slip rates, provide tool for evaluating the organization contemporary faulting in southeastern Alaska. The primary structural features considered our analysis are Denali, Duke River, Totschunda, Fairweather, Queen Charlotte, and Transition faults. combination fault configurations rheological properties that best explains observed rates predicts Fairweather Totschunda faults joined an inferred southeast-trending strike-slip crosses St. Elias Mountains. From regional perspective, this structure, which models suggest slips at rate ∼8 mm/a, transfers shear from Charlotte Alaska British Columbia northward to Denali central This result supports previous hypotheses Fairweather-Totschunda connecting constitutes newly established extension Charlotte-Fairweather transform system helps accommodate right-lateral motion (∼49 mm/a) Pacific plate Yakutat microplate relative stable North America. Model results also imply separating is favorably oriented significant thrusting (23 mm/a). Rapid dip-slip displacement on does not, however, draw off system. Our new modeling fault, proposed may represent youngest stage southwestward migration active deformation front long-term evolution convergent margin.