Okinawa

History

The past. At the ice age peak the sea stood about 120 metres lower, and some 20,000 square kilometres of this plate’s shallow sea was dry land, more than doubling its land. Okinawa was about three times its size, and Tanegashima and Yakushima were joined to Kyushu. From the Tokara islands south, deep straits still kept the islands apart from Kyushu and Taiwan, and people reached them by sea about 35,000 years ago. The land was already largely dry when the timeline begins; the rising sea drowned most of it between 16,416 and 8,296 years ago. About 7,300 years ago the Kikai caldera, south of Kyushu, erupted in one of the largest eruptions of the last 10,000 years, and grass replaced the forest at the southern tip of Kyushu for several centuries. The line that stands for the shallow sea turns about halfway to the colour of land, all at once, and only across those spans.

2 million years ago

The Okinawa Trough behind this plate's arc began its latest phase of pulling apart; it is still a young back-arc basin.

Sources: Lambeck et al. 2014, PNAS 111:15296; Fujita et al. 2016, PNAS 113:11184; Kaifu et al. 2020, Scientific Reports 10:19785; Saito 1998, The Quaternary Research 37:235; Tatsumi et al. 2018, Scientific Reports 8:2753; Sugiyama 2002, The Quaternary Research 41:311; Uchiyama et al. 2023, Antiquity 97:557 · Sibuet et al. 1998, Journal of Geophysical Research 103:30245