The Seto Inland Sea has been fit to develop industrialization because there were plenty of shallow coast where were suitable for industry and plenty of labor force about 30,000,000 people.
The heavy and chemical industries have been developed around the Seto Inland Sea according to the extremely strong requirement to the industry, which is endorsed doubling income policy after 1955. The production ability there of key industries such as iron and steal industry, oil refinery industry, petrochemical industry and so on occupies more than 30 % of that in Japan although the ratio of industrial shipping amount in this areas has decreased. The trend of industrial shipping amount of the 13 prefectures is shown in Figure2-3.
With regard to gravel and sand, which are important building material in Japan, about 17 % of the amount of the former and about 65 % of the latter are produced from the area of the Seto Inland Sea in 1996. The trend of the produced amount is shown in Figure 2-4.
Note: after data by Ministry of International Trade and Industry
Figure 2-3 Trend of Industrial Shipping Amount in the Prefectures Concerned
Note: after data by Ministry of International Trade and Industry
Figure 2-4 Trend of the Produced Amount of Gravel and Sand in the Seto Inland Sea