Surface rupturing earthquakes repeated in the 300 years along the ISTL active fault system, central Japan. Issue 12 (27th June 2017)

• Record Type: Journal Article
• Authors: Katsube, Aya; Kondo, Hisao; Kurosawa, Hideki
• Is Part Of: Geophysical research letters. Volume 44:Issue 12(2017)
• Page Start: 6057
• Page End: 6064
• Publication Date: 2017-06-27
• Subjects: crustal earthquake -- active fault -- paleoseismology; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2017GL073746
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Surface rupturing earthquakes produced by intraplate active faults generally have long recurrence intervals of a few thousands to tens of thousands of years. We here report the first evidence for an extremely short recurrence interval of 300 years for surface rupturing earthquakes on an intraplate system in Japan. The Kamishiro fault of the Itoigawa‐Shizuoka Tectonic Line (ISTL) active fault system generated a M w 6.2 earthquake in 2014. A paleoseismic trench excavation across the 2014 surface rupture showed the evidence for the 2014 event and two prior paleoearthquakes. The slip of the penultimate earthquake was similar to that of 2014 earthquake, and its timing was constrained to be after A.D. 1645. Judging from the timing, the damaged area, and the amount of slip, the penultimate earthquake most probably corresponds to a historical earthquake in A.D. 1714. The recurrence interval of the two most recent earthquakes is thus extremely short compared with intervals on other active faults known globally. Furthermore, the slip repetition during the last three earthquakes is in accordance with the time‐predictable recurrence model rather than the characteristic earthquake model. In addition, the spatial extent of the 2014 surface rupture accords with the distribution of a serpentinite block, suggesting that the relatively low coefficient of friction may account for the unusually frequent earthquakes. These findings would affect long‐term forecast of earthquake probability and seismic hazard assessment on active faults. Key Points: Paleoseismic trench excavation revealed the Kamishiro fault ruptured in 2014 and 1714 A.D. with the 300 years recurrence interval The reconstructed time‐slip diagram for the last three earthquakes is consistent with the time‐predictable earthquake model The irregular recurrence behavior may be affected by low coefficient friction of serpentinite block along the fault