Reactivation of map-scale faults in response to changes in crustal stress: Examples from Boso Peninsula, Japan. (15th October 2017)

• Record Type: Journal Article
• Authors: Otsubo, Makoto; Utsunomiya, Masayuki; Miyakawa, Ayumu
• Is Part Of: Quaternary international. Volume 456(2017)
• Page Start: 117
• Page End: 124
• Publication Date: 2017-10-15
• Subjects: Forearc basin -- Kanto region -- Mesoscale fault -- Slickenline -- Stress field -- Subduction; Geology, Stratigraphic -- Quaternary -- Periodicals; Stratigraphie -- Quaternaire -- Périodiques; 551.79
• DOI: 10.1016/j.quaint.2017.05.057
• Languages: English
• ISSNs: 1040-6182

Abstract

Abstract: We have investigated the reactivation of Quaternary faults near the trench-trench-trench type triple junction off Boso Peninsula, central Japan. On the Pacific side of the Boso Peninsula (PSBP region), map-scale NNE–SSW-trending faults developed during ∼1.2–0.7 Ma, although these faults are inactive at present. We observed multiple and overlapped slickenlines on parts of map-scale fault planes in the PSBP region. These slickenlines can be classified into two different directions, which we consider to be the reactivation of the map-scale faults in response to a change in crustal stress after ∼1 Ma. Based on angular misfits between the predicted and observed slip directions, we successfully compared the older and younger slip directions to dip-slip normal faulting and oblique sinistral normal faulting, respectively. The reactivation of the map-scale faults in response to a relatively short (10 5 yrs) stress change has been verified based on the direct evidences on the map-scale fault planes. Highlights: Cross-cutting slickenlines exist on Quaternary map-scale faults in the PSBP region, Japan. The map-scale faults in the PSBP region responded to a stress change on a timescale of 10 5 yrs after ∼1 Ma. The changes in crustal stresses are important in understanding the evolution of activity on faults.