Megascopic geological structures in Niigata Prefecture and its surrounding area, northeastern Japan

—Two tectonic models for NNE-, NW- to WNW-, and NNW- to N-striking megascopic geological structures in northeast Japan arc—

Abstract

In this paper I construct a macroscopic geological structural map of northern Honshu, Japan, including Niigata Prefecture, in order to comprehend its structural features. I also propose two tectonic models for late Cenozoic tectonics of northern Honshu and Japan Sea opening in particular: strike-slip fault system and rift system. The latter system consists of first- and second-order (smaller scale) rift systems. Both rift systems have three arms of a triple junction. During Japan Sea opening, two of the three arms failed or stopped spreading in a shorter time than the third arm.