Brief explanation on the regional characteristics of Sanriku Coast
The 2011 East Japan Earthquake Bulletin of the Tohoku
1. IntroductionThis short note provides a brief description on the regional characteristics of Sanriku Coast, northeast Honshu Island（Fig.1）. Sanriku Coast is a local name covers the Pacific side of northeast Honshu island. Almost entire part of Sanriku Coast was severely devastated by the Huge earthquake and Tsunami at 11, March, 2011. Many of fishing ports and coastal towns or villages were entirely devastated by the huge Tsumani up to 10m or higher.
2. Physical backgroundsRemarkable characteristics of land form are saw-toothed coastline with narrow flat land, which is known as “Ria coast”. Such shape of coastline turns to be a factor which increase the height of tsumami（Fig.2). In fact, Sanriku coast suffered from severe tsumami disasters at three times in the past, Meiji Sanriku Tsumami in 1896, Showa Sanriku Tsunami in 1933, and Chile Earthquake Tsunami in 1960.
Through such experiences, people in Sanriku Coast had taken many preventive measures against periodically coming tsunami, such as upward move of the settlements, construction huge seawalls, making map for escaping from natural disasters including tsunami, and periodical practice for it. But it would be truly regrettable that such measures couldn’t work effectively this time, because of its scale beyond prediction.
As for the climate, Sanriku Coast, like as the most of north-eastern part of Japan, suffer sometimes from the cold summer caused mainly by the cold current and the cold northeast wind blowing from the cold air mass staying over Okhotsk Sea. Owing it, Sanriku Coast has least advantages for agriculture.On the other hand, Sanriku Coast has one of the richest sea for the fishery resources, which made the area one of major fishery regions not only in Japan but also in the world.
3. Population and citiesAs shown in Fig.3, population in Sanriku Coast is relatively dispersed than the inland area along the arterial traffic route between Sendai and Morioka. The Change Ratios (1990〜2000) show “minus” in most of municipalities in Sanriku Coast. Major cities in Sanriku Coast such as Hachinohe（八戸）, Miyako（宮古）, Kamaishi（釜石）, Ofunato（大船渡）, Kesennuma（気仙沼）, Onagawa（女川）, Ishinomaki（石巻）, developed with their functions of fishing base port during mainly Japan’s rapid economic growth after 1960’s. Hachinohe is known as the biggest base port of far-sea squid fishing in the world. Kesennuma is famous as the world biggest base port for Tuna fishing and shark’s fin production. Many merchants and manufacturers of the marine products and seamen gathered from adjacent villages to these major fishing ports.
In 1970’s when the northern Pacific fishery was prosperous, and in 1980’s when resources of the migratory fishes were rich, these fishing ports thrived. After 1990’s, catch of fishes and fishery workers had rapidly decreased, because of the movement of international regulation for the fishing, and decease of the marine resources itself. In the result, population itself decreased as shown in Fig.3. But even now, Sanriku Coast is a major fishery and marine food production region in Japan (Fig.4).
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