GEOLOGY

Detailed explanation-1: -The main part of the Japanese arc system contains four big islands: Hokkaido, Honshu, Shikoku, and Kyushu (Figure 1b). The term southwest (SW) Japan indicates that part of the arc that encompasses southwestern Honshu and Shikoku.

Detailed explanation-2: -The Japanese Island Arcs are located on the boundaries between the Pacific Plate, Philippine Sea Plate, North American Plate (or Okhotsk Plate; Seno & Sakurai 1996) and Eurasia Plate (or Amurian Plate and South China Plate; Heki et al. 1999).

Detailed explanation-3: -The Northeastern Japan Arc, also Northeastern Honshū Arc, is an island arc on the Pacific Ring of Fire. The arc runs north to south along the Tōhoku region of Honshū, Japan. It is the result of the subduction of the Pacific Plate underneath the Okhotsk Plate at the Japan Trench.

Detailed explanation-4: -Some well-known examples of island arcs are Japan, Aleutian Islands of Alaska, Mariana Islands, all of which are in the Pacific, and the Lesser Antilles in the Caribbean. The abundance of volcanic rocks around the Pacific Ocean has led to the designation of the Pacific margin as a “Ring of Fire”.

Detailed explanation-5: -An archipelago made up of oceanic islands is called an island arc.