Háskóli ÍslandsUniversity of IcelandBjarnason, Ingi ÞorleifurCowie, PatienceAnders, Mark H.Seeber, LeonardoScholz, Christopher H.2018-01-052018-01-051993Ingi Th. Bjarnason, Patience Cowie, Mark H. Anders, Leonardo Seeber, Christopher H. Scholz; The 1912 Iceland earthquake rupture: Growth and development of a nascent transform system. Bulletin of the Seismological Society of America ; 83 (2): 416–435.0037-11061943-3573 (eISSN)https://hdl.handle.net/20.500.11815/502We have mapped in detail surface ruptures of the 1912 magnitude 7.0 strike-slip earthquake in south Iceland. This earthquake ruptured fresh basalt flows that had covered the pre-existing fault. The observed style of surface fracturing closely matches both theoretical predictions of the first stages of shear fracture development and microscopic-scale observations from laboratory experiments. The shear offset distributed across the zone of surface fractures produced by this earthquake is right-lateral and is in the range of 1 to 3 m. Total mapped rupture length is 9 km, but total rupture length is probably at least ∼ 20 km. This interplate earthquake had an exceptionally high ratio of slip to fault length and, by inference, stress drop. The north-south trending rupture of the 1912 earthquake is part of the “bookshelf” faulting in the east-west trending South Iceland Seismic Zone. We ascribe the “bookshelf” faulting in the South Iceland Seismic Zone to a combination of the early development stage of the transform and regional strength anisotropy of the crust.416-435eninfo:eu-repo/semantics/openAccessJarðskjálftarJarðskjálftarannsóknirinfo:eu-repo/semantics/articleBulletin of the Seismological Society of America