Geomorphological evolution of the Notsukesaki barrier spit controlled by forced regression

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K05323
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Geology
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: Nanayama Futoshi 国立研究開発法人産業技術総合研究所, 地質調査総合センター, 上級主任研究員 (20357685)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: バリアースピット / 分岐砂嘴 / 野付崎 / 地形発達史 / 現行過程 / 地震テクトニクス / 千島海溝 / 北海道

Outline of Final Research Achievements

The Notsukesaki barrier spit system (NBS) is part of an active barrier system facing Nemuro Strait. There are four clearly defined spit branches within the barrier system. We used topographic profiles, hand core and trenching, grain size analysis, AMS 14C dating, and tephrochronology to determine the chronology of the development of the four spits of the system. Taking into account the times of their emergence and the present elevations of the landward limits of their backshores, we constructed a relative sea level curve that is reasonably consistent with episodic regional coseismic events that have uplifted coastal areas along the southern Kuril subduction zone by 2-3 m at intervals of ~500 years. These events have interrupted a period of otherwise continuous subsidence in the study area since the 17th century and have led to the development of individual spits within the barrier system. Thus, we have demonstrated the seismotectonic control of the geomorphological evolution of NBS.

Free Research Field

堆積学，地質学，地形学