Abstract

We map the fault planes of M≥7.0 earthquakes along the Sumatran fault in Sumatra, western Indonesia, for the period since 1892. To obtain precise hypocenter locations of large earthquakes and identify fault planes of M≥7.0 earthquakes, we relocated 27 M≥6.0 earthquakes from 1921 to 2012 using the modified joint hypocenter determination method. We found that six M≥7.0 events appear to have occurred on segments of the Sumatran fault as follows: Kumering for the 1933 (Ms 7.5) event; the northwestern and southeastern parts of Tripa for the 1935 (Ms 7.0) and 1936 (Ms 7.2) events, respectively; the southeastern half of Sunda for the April 1943 (Ms 7.1) event; Ketaun for the first (Ms 7.3) event of the June 1943 doublet; and Suliti and Sumani for the second (Ms 7.6) event of the June 1943 doublet. We also identified the faults of four M≥7.0 earthquakes between 1892 and 1920 by using information on crustal deformation and damage distributions. From the results of earthquake locations between 1892 and 2012, and the corresponding fault lengths of M≥7.0 earthquakes, we have interpreted the large (M≥7.0) earthquake history of the Sumatran fault for the past 120 years. Possible seismic gaps for M≥7.0 earthquakes along the Sumatran fault are the northern half of the Sunda segment, and the Semangko, Dikit, Sianok, Barumun, Toru, Renun, Aceh, and Seulimeum segments.

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