| With a predominant westward direction, the migration of earthquakes makes the North Anatolian fault in Turkey an ideal natural laboratory for studying how earthquakes interact along major fault systems. This study explores the mechanical interaction and stress triggering relationships between past earthquake ruptures and evaluates the future rupture potential in the Marmara Sea region.; The stress perturbation associated with the 1967 Mudurnu Valley earthquake helped trigger the 1999 Izmit earthquake. However, test of different potential rupture geometries of the 1967 event show that only if this rupture extended in the subsurface towards the 1999 Izmit segments, do the Izmit faults receive greater stress loading than all other neighboring faults.; The likelihood for an earthquake rupture to propagate along obliquely-oriented intersecting fault segments, as observed in the 1999 Izmit earthquake, depends on the relative orientations of the faults. Static Coulomb stress changes indicate that when a secondary fault strikes counterclockwise relative to a master strike-slip fault, a dipping secondary fault will fail more readily than a vertical fault. For a clockwise change in strike, a vertical fault will fail more readily than a dipping fault. The pre-existing fault segment geometries at the eastern end of the Izmit earthquake helped terminate rupture there and fault intersections of several major faults in the Marmara Sea favor composite rupture geometry.; Incorporating geophysical data with geomechanical modeling shows that, of several proposed configurations, a Marmara Sea fault geometry composed of several large east-west trending strike-slip strands with multiple fault strands bounding individual basins best fits the observed seafloor morphology and pattern of stratigraphic horizon deformation.; Coulomb stresses changes due to earthquakes since 1900 are increased on the Princes' Island, Cinarcik, and Armutlu fault segments within the eastern Marmara Sea. In four of the six plausible configurations for the western termination of the 1999 Izmit rupture and the location of the 1963 Yalova earthquake, the Cinarcik fault receives the greatest average stress change. In another cases, the stress increase on the Princes' Islands fault is greatest. Although it is difficult to conclude which rupture scenario is most plausible, the results identify the consequences of each configuration. |
