摘要:The ground deformation and fault slip model for the 1891 M 8.0 Nobi earthquake, central Japan, have been reexamined.The Nobi earthquake appears to have occurred mainly due to the rupture of three faults: Nukumi, Neodani, and Umehara.Since triangulation and leveling had been performed around the Umehara fault, the two geodetic datasets from 1885–1890 and 1894–1908 have been reevaluated.Maximum coseismic horizontal displacements of 1.7 m were detected to the south of the Neodani fault.A fault model of the Nobi earthquake was estimated from the geodetic datasets, taking into account the geometry of the fault planes based on the known surface ruptures.The best fit to the data was obtained from three and four divided fault segments running along the Nukumi, Neodani, and Umehara faults; although, in past studies, the Gifu-Ichinomiya line has been suggested as a buried fault to explain the ground deformation.The detected ground deformation can be well reproduced using a slip model for the Umehara fault, dipping at 61° toward the southwest, with a maximum slip of 3.8 m in the deeper northwestern segment.As this model suitably explains the coseismic deformation, the earthquake source fault does not appear to extend to the Gifu-Ichinomiya line. Key words 1891 Nobi earthquake fault model triangulation leveling Gifu-Ichinomiya line.
关键词:1891 Nobi earthquake ;fault model ;triangulation ;leveling ;Gifu-Ichinomiya line