フィリピン海プレート
The Pacific Plate and Philippine Sea Plate are subduction plates. They are deeper than the Eurasian plate. The Philippine Sea Plate moves beneath the continental Amurian Plate and Okinawa Plate to the south. The Pacific Plate moves under the Okhotsk Plate to the north. These subduction plates have pulled Japan eastward and opened the Sea of Japan by back-arc spreading around 15 million years ago. The Strait of Tartary and the Korea Strait opened much later. La Pérouse Strait formed about 60,000 to 11,000 years ago closing the path used by mammoths which had earlier moved to northern Hokkaido.