表−2(3) 粒度分布の経年変化   (単位:%)
| No | 
湾名 | 
1980-1 | 
1980-2 | 
1985 | 
1990 | 
1995 | 
1999-1 | 
1999-2 | 
平均 | 
最小 | 
最大 | 
| 5 | 
伊勢湾 | 
I1 | 
礫 | 
3.0 | 
  | 
0.2 | 
0.0 | 
2.0 | 
0.0 | 
  | 
1.0 | 
0.0 | 
3.0 | 
| 粗・中砂 | 
1.8 | 
  | 
0.6 | 
0.2 | 
0.4 | 
0.0 | 
  | 
0.6 | 
0.0 | 
1.8 | 
| 細砂 | 
4.2 | 
  | 
1.4 | 
0.2 | 
0.1 | 
0.2 | 
  | 
1.2 | 
0.1 | 
4.2 | 
| シルト | 
61.0 | 
  | 
40.2 | 
44.3 | 
53.8 | 
33.4 | 
  | 
46.5 | 
33.4 | 
61.0 | 
| 粘土 | 
30.0 | 
  | 
57.6 | 
55.3 | 
43.7 | 
66.4 | 
  | 
50.6 | 
30.0 | 
66.4 | 
| 中央粒径(μm) | 
13 | 
  | 
*4 | 
*4 | 
5 | 
*4 | 
  | 
6.0 | 
*4 | 
13 | 
| I2 | 
礫 | 
0.0 | 
  | 
0.2 | 
0.0 | 
0.0 | 
0.0 | 
  | 
0.0 | 
0.0 | 
0.2 | 
| 粗・中砂 | 
0.1 | 
  | 
1.1 | 
0.1 | 
0.1 | 
0.0 | 
  | 
0.3 | 
0.0 | 
1.1 | 
| 細砂 | 
1.4 | 
  | 
3.7 | 
0.1 | 
0.2 | 
0.8 | 
  | 
1.2 | 
0.1 | 
3.7 | 
| シルト | 
6.3 | 
  | 
40.7 | 
40.2 | 
68.6 | 
32.8 | 
  | 
37.7 | 
6.3 | 
68.6 | 
| 粘土 | 
36.0 | 
  | 
54.3 | 
59.6 | 
31.1 | 
66.4 | 
  | 
49.5 | 
31.1 | 
66.4 | 
| 中央粒径(μm) | 
9 | 
  | 
*4 | 
*4 | 
7 | 
*4 | 
  | 
5.6 | 
*4 | 
9 | 
| I3 | 
礫 | 
0.1 | 
  | 
0.4 | 
0.0 | 
0.0 | 
0.0 | 
  | 
0.1 | 
0.0 | 
0.4 | 
| 粗・中砂 | 
0.2 | 
  | 
2.6 | 
0.1 | 
0.5 | 
0.0 | 
  | 
0.7 | 
0.0 | 
2.6 | 
| 細砂 | 
8.5 | 
  | 
5.4 | 
0.3 | 
0.3 | 
0.4 | 
  | 
3.0 | 
0.3 | 
8.5 | 
| シルト | 
53.2 | 
  | 
36.7 | 
61.3 | 
62.7 | 
51.8 | 
  | 
53.1 | 
36.7 | 
62.7 | 
| 粘土 | 
37.0 | 
  | 
54.9 | 
38.3 | 
36.5 | 
47.8 | 
  | 
42.9 | 
36.5 | 
54.9 | 
| 中央粒径(μm) | 
9 | 
  | 
*4 | 
6 | 
6 | 
4 | 
  | 
5.8 | 
*4 | 
9 | 
| I4 | 
礫 | 
0.0 | 
  | 
0.3 | 
0.0 | 
0.0 | 
0.0 | 
  | 
0.1 | 
0.0 | 
0.3 | 
| 粗・中砂 | 
0.9 | 
  | 
1.8 | 
1.7 | 
0.5 | 
1.1 | 
  | 
1.2 | 
0.5 | 
1.8 | 
| 細砂 | 
4.0 | 
  | 
66.0 | 
68.4 | 
52.0 | 
64.8 | 
  | 
51.0 | 
4.0 | 
68.4 | 
| シルト | 
36.9 | 
  | 
22.1 | 
21.1 | 
36.2 | 
20.4 | 
  | 
27.3 | 
20.4 | 
36.9 | 
| 粘土 | 
58.3 | 
  | 
9.8 | 
8.8 | 
11.3 | 
13.7 | 
  | 
20.4 | 
8.8 | 
58.3 | 
| 中央粒径(μm) | 
*4 | 
  | 
84 | 
106 | 
66 | 
81 | 
  | 
68.2 | 
*4 | 
106 | 
| I5 | 
礫 | 
86.1 | 
  | 
0.2 | 
0.2 | 
0.0 | 
0.0 | 
  | 
17.3 | 
0.0 | 
86.1 | 
| 粗・中砂 | 
8.8 | 
  | 
61.8 | 
45.1 | 
36.0 | 
14.0 | 
  | 
33.1 | 
8.8 | 
61.8 | 
| 細砂 | 
1.2 | 
  | 
37.2 | 
47.4 | 
63.0 | 
82.5 | 
  | 
46.3 | 
1.2 | 
82.5 | 
| シルト | 
1.9 | 
  | 
0.8 | 
1.9 | 
0.2 | 
1.4 | 
  | 
1.2 | 
0.2 | 
1.9 | 
| 粘土 | 
2.1 | 
  | 
0.0 | 
5.4 | 
0.8 | 
2.1 | 
  | 
2.1 | 
0.0 | 
5.4 | 
| 中央粒径(μm) | 
2000 | 
  | 
298 | 
234 | 
212 | 
180 | 
  | 
584.8 | 
180 | 
2000 | 
| 6 | 
大阪湾 | 
O1 | 
礫 | 
0.4 | 
  | 
0.0 | 
0.0 | 
0.0 | 
0.0 | 
  | 
0.1 | 
0.0 | 
0.4 | 
| 粗・中砂 | 
3.6 | 
  | 
0.7 | 
0.3 | 
0.4 | 
0.6 | 
  | 
1.1 | 
0.3 | 
3.6 | 
| 細砂 | 
6.2 | 
  | 
1.8 | 
0.6 | 
0.3 | 
0.2 | 
  | 
1.8 | 
0.2 | 
6.2 | 
| シルト | 
38.8 | 
  | 
45.9 | 
44.2 | 
66.7 | 
51.8 | 
  | 
49.5 | 
38.8 | 
66.7 | 
| 粘土 | 
51.0 | 
  | 
51.6 | 
54.9 | 
32.6 | 
47.4 | 
  | 
47.5 | 
32.6 | 
54.9 | 
| 中央粒径(μm) | 
*4 | 
  | 
4 | 
*4 | 
10 | 
5 | 
  | 
5.4 | 
*4 | 
10 | 
| O2 | 
礫 | 
0.0 | 
  | 
0.0 | 
0.1 | 
0.2 | 
0.0 | 
  | 
0.1 | 
0.0 | 
0.2 | 
| 粗・中砂 | 
1.7 | 
  | 
0.2 | 
0.4 | 
0.5 | 
0.3 | 
  | 
0.6 | 
0.2 | 
1.7 | 
| 細砂 | 
6.4 | 
  | 
2.2 | 
0.4 | 
0.7 | 
0.4 | 
  | 
2.0 | 
0.4 | 
6.4 | 
| シルト | 
58.4 | 
  | 
50.6 | 
67.1 | 
74.1 | 
47.7 | 
  | 
59.6 | 
47.7 | 
74.1 | 
| 粘土 | 
33.5 | 
  | 
47.0 | 
32.0 | 
24.5 | 
51.6 | 
  | 
37.7 | 
24.5 | 
51.6 | 
| 中央粒径(μm) | 
14 | 
  | 
5 | 
8 | 
14 | 
*4 | 
  | 
9.0 | 
*4 | 
14 | 
| O3 | 
礫 | 
0.2 | 
  | 
0.0 | 
0.0 | 
0.0 | 
0.0 | 
  | 
0.0 | 
0.0 | 
0.2 | 
| 粗・中砂 | 
0.9 | 
  | 
0.3 | 
0.2 | 
0.6 | 
0.2 | 
  | 
0.4 | 
0.2 | 
0.9 | 
| 細砂 | 
7.1 | 
  | 
1.0 | 
0.7 | 
0.6 | 
0.7 | 
  | 
2.0 | 
0.6 | 
7.1 | 
| シルト | 
46.8 | 
  | 
44.1 | 
67.6 | 
77.0 | 
62.7 | 
  | 
59.6 | 
44.1 | 
77.0 | 
| 粘土 | 
45.0 | 
  | 
54.6 | 
31.5 | 
21.8 | 
36.4 | 
  | 
37.9 | 
21.8 | 
54.6 | 
| 中央粒径(μm) | 
6 | 
  | 
*4 | 
7 | 
14 | 
7 | 
  | 
7.6 | 
*4 | 
14 | 
| O4 | 
礫 | 
1.1 | 
  | 
0.0 | 
0.0 | 
0.2 | 
0.0 | 
  | 
0.3 | 
0.0 | 
1.1 | 
| 粗・中砂 | 
5.0 | 
  | 
0.2 | 
0.2 | 
0.5 | 
0.1 | 
  | 
1.2 | 
0.1 | 
5.0 | 
| 細砂 | 
20.6 | 
  | 
12.3 | 
8.0 | 
17.8 | 
13.4 | 
  | 
14.4 | 
8.0 | 
20.6 | 
| シルト | 
41.3 | 
  | 
46.0 | 
56.8 | 
61.5 | 
62.3 | 
  | 
53.6 | 
41.3 | 
62.3 | 
| 粘土 | 
32.0 | 
  | 
41.5 | 
35.0 | 
20.0 | 
24.2 | 
  | 
30.5 | 
20.0 | 
41.5 | 
| 中央粒径(μm) | 
18 | 
  | 
7 | 
9 | 
26 | 
8 | 
  | 
13.6 | 
7 | 
26 | 
| O5 | 
礫 | 
0.1 | 
  | 
0.1 | 
1.3 | 
1.2 | 
0.4 | 
  | 
0.6 | 
0.1 | 
1.3 | 
| 粗・中砂 | 
1.6 | 
  | 
3.0 | 
11.6 | 
7.2 | 
4.5 | 
  | 
5.6 | 
1.6 | 
11.6 | 
| 細砂 | 
50.1 | 
  | 
59.9 | 
55.4 | 
57.1 | 
49.6 | 
  | 
54.4 | 
49.6 | 
59.9 | 
| シルト | 
25.7 | 
  | 
16.1 | 
17.9 | 
19.1 | 
27.3 | 
  | 
21.2 | 
16.1 | 
27.3 | 
| 粘土 | 
22.5 | 
  | 
20.9 | 
13.8 | 
15.4 | 
18.2 | 
  | 
18.2 | 
13.8 | 
22.5 | 
| 中央粒径(μm) | 
70 | 
  | 
91 | 
148 | 
129 | 
79 | 
  | 
103.4 | 
70 | 
148 | 
 
注)1.*は中央粒径が4μm未満のもの。平均の算出において、4μmとして算出した。
2.鹿児島湾(全域)は1980年欠測のため、1981年のデータを引用。
出典)「海洋汚染調査報告」(海上保安庁水路部)
表−2(4) 粒度分布の経年変化      (単位: %)
| No | 
湾名 | 
Jan-80 | 
Feb-80 | 
1985 | 
1990 | 
1995 | 
Jan-99 | 
Feb-99 | 
平均 | 
最小 | 
最大 | 
| 7 | 
紀伊水道 | 
O6 | 
礫 | 
0.4 | 
  | 
0 | 
0 | 
0.1 | 
0.3 | 
  | 
0.2 | 
0 | 
0.4 | 
| 粗・中砂 | 
7.1 | 
  | 
3.6 | 
2.8 | 
3.3 | 
5.2 | 
  | 
4.4 | 
2.8 | 
7.1 | 
| 細砂 | 
68 | 
  | 
65.8 | 
64.3 | 
49.4 | 
54.6 | 
  | 
60.4 | 
49.4 | 
68 | 
| シルト | 
13 | 
  | 
16.3 | 
19.1 | 
30.3 | 
22.5 | 
  | 
20.2 | 
13 | 
30.3 | 
| 粘土 | 
11.5 | 
  | 
14.3 | 
13.8 | 
16.9 | 
17.4 | 
  | 
14.8 | 
11.5 | 
17.4 | 
| 中央粒径(μm) | 
130 | 
  | 
103 | 
114 | 
72 | 
85 | 
  | 
100.8 | 
72 | 
130 | 
| O7 | 
礫 | 
0 | 
  | 
0 | 
0 | 
0 | 
0 | 
  | 
0 | 
0 | 
0 | 
| 粗・中砂 | 
0 | 
  | 
0 | 
0.1 | 
0 | 
0 | 
  | 
0 | 
0 | 
0.1 | 
| 細砂 | 
10.4 | 
  | 
4 | 
3.2 | 
1 | 
1.7 | 
  | 
4.1 | 
1 | 
10.4 | 
| シルト | 
67.1 | 
  | 
66.3 | 
72.6 | 
78 | 
77.1 | 
  | 
72.2 | 
66.3 | 
78 | 
| 粘土 | 
22.5 | 
  | 
29.7 | 
24.1 | 
21 | 
21.2 | 
  | 
23.7 | 
21 | 
29.7 | 
| 中央粒径(μm) | 
19 | 
  | 
9 | 
11 | 
15 | 
10 | 
  | 
12.8 | 
9 | 
19 | 
| O8 | 
礫 | 
4.5 | 
  | 
  | 
3.9 | 
1.2 | 
0.6 | 
  | 
2.6 | 
0.6 | 
4.5 | 
| 粗・中砂 | 
16.5 | 
  | 
  | 
17.7 | 
23 | 
13.7 | 
  | 
17.7 | 
13.7 | 
23 | 
| 細砂 | 
37.6 | 
  | 
  | 
42 | 
42.2 | 
39.5 | 
  | 
40.3 | 
37.6 | 
42.2 | 
| シルト | 
24.6 | 
  | 
  | 
20.1 | 
25 | 
26.1 | 
  | 
24 | 
20.1 | 
26.1 | 
| 粘土 | 
16.8 | 
  | 
  | 
16.3 | 
8.6 | 
20.1 | 
  | 
15.5 | 
8.6 | 
20.1 | 
| 中央粒径(μm) | 
95 | 
  | 
  | 
126 | 
115 | 
72 | 
  | 
102 | 
72 | 
126 | 
| O9 | 
礫 | 
0 | 
  | 
  | 
0.1 | 
0 | 
0 | 
  | 
0 | 
0 | 
0.1 | 
| 粗・中砂 | 
10.1 | 
  | 
  | 
8.4 | 
11.4 | 
9.8 | 
  | 
9.9 | 
8.4 | 
11.4 | 
| 細砂 | 
73.5 | 
  | 
  | 
69.7 | 
70.5 | 
67.9 | 
  | 
70.4 | 
67.9 | 
73.5 | 
| シルト | 
8.2 | 
  | 
  | 
13.4 | 
12.3 | 
14 | 
  | 
12 | 
8.2 | 
14 | 
| 粘土 | 
8.2 | 
  | 
  | 
8.4 | 
5.8 | 
8.3 | 
  | 
7.7 | 
5.8 | 
8.4 | 
| 中央粒径(μm) | 
155 | 
  | 
  | 
150 | 
145 | 
112 | 
  | 
140.5 | 
112 | 
155 | 
| 8 | 
瀬戸内海 | 
N1 | 
礫 | 
0.1 | 
  | 
0.1 | 
0 | 
0 | 
0 | 
  | 
0 | 
0 | 
0.1 | 
| 粗・中砂 | 
7 | 
  | 
1 | 
0.7 | 
0.3 | 
0.5 | 
  | 
1.9 | 
0.3 | 
7 | 
| 細砂 | 
19.1 | 
  | 
11.9 | 
9.5 | 
5.4 | 
5.7 | 
  | 
10.3 | 
5.4 | 
19.1 | 
| シルト | 
40.5 | 
  | 
51.5 | 
53.7 | 
64.3 | 
39 | 
  | 
49.8 | 
39 | 
64.3 | 
| 粘土 | 
33.3 | 
  | 
35.5 | 
36.1 | 
30 | 
54.8 | 
  | 
37.9 | 
30 | 
54.8 | 
| 中央粒径(μm) | 
18 | 
  | 
12 | 
7 | 
8 | 
*4 | 
  | 
9.8 | 
*4 | 
18 | 
| N3 | 
礫 | 
0.1 | 
  | 
0.1 | 
0 | 
0 | 
0 | 
  | 
0 | 
0 | 
0.1 | 
| 粗・中砂 | 
2.2 | 
  | 
1.5 | 
0.2 | 
0.4 | 
1.9 | 
  | 
1.2 | 
0.2 | 
2.2 | 
| 細砂 | 
80.1 | 
  | 
80.4 | 
78.2 | 
68.3 | 
79 | 
  | 
77.2 | 
68.3 | 
80.4 | 
| シルト | 
7.3 | 
  | 
4.3 | 
10.2 | 
20.3 | 
12.8 | 
  | 
11 | 
4.3 | 
20.3 | 
| 粘土 | 
10.3 | 
  | 
13.7 | 
9.6 | 
11 | 
6.3 | 
  | 
10.2 | 
6.3 | 
13.7 | 
| 中央粒径(μm) | 
135 | 
  | 
114 | 
155 | 
115 | 
115 | 
  | 
126.8 | 
114 | 
155 | 
| N5 | 
礫 | 
0.2 | 
  | 
0 | 
0 | 
0 | 
0 | 
  | 
0 | 
0 | 
0.2 | 
| 粗・中砂 | 
0.9 | 
  | 
0.4 | 
0.2 | 
0.1 | 
0.2 | 
  | 
0.4 | 
0.1 | 
0.9 | 
| 細砂 | 
36 | 
  | 
25.9 | 
13 | 
11.5 | 
19.5 | 
  | 
21.2 | 
11.5 | 
36 | 
| シルト | 
39.4 | 
  | 
42.3 | 
59.2 | 
71.7 | 
52.1 | 
  | 
52.9 | 
39.4 | 
71.7 | 
| 粘土 | 
23.5 | 
  | 
31.4 | 
27.6 | 
16.7 | 
28.2 | 
  | 
25.5 | 
16.7 | 
31.4 | 
| 中央粒径(μm) | 
41 | 
  | 
25 | 
12 | 
23 | 
14 | 
  | 
23 | 
12 | 
41 | 
| N7 | 
礫 | 
0 | 
  | 
4.2 | 
0 | 
0 | 
0 | 
  | 
0.8 | 
0 | 
4.2 | 
| 粗・中砂 | 
1.2 | 
  | 
0.3 | 
0.1 | 
0.1 | 
0 | 
  | 
0.3 | 
0 | 
1.2 | 
| 細砂 | 
6.5 | 
  | 
2.2 | 
0.7 | 
0.5 | 
0.6 | 
  | 
2.1 | 
0.5 | 
6.5 | 
| シルト | 
49.3 | 
  | 
53.3 | 
41.8 | 
66.7 | 
56.3 | 
  | 
53.5 | 
41.8 | 
66.7 | 
| 粘土 | 
43 | 
  | 
40 | 
57.4 | 
32.7 | 
43.1 | 
  | 
43.2 | 
32.7 | 
57.4 | 
| 中央粒径(μm) | 
6 | 
  | 
6 | 
*4 | 
7 | 
5 | 
  | 
5.6 | 
*4 | 
7 | 
| N10 | 
礫 | 
0.1 | 
  | 
0 | 
0 | 
0 | 
0 | 
  | 
0 | 
0 | 
0.1 | 
| 粗・中砂 | 
0.7 | 
  | 
0.1 | 
0 | 
0 | 
0 | 
  | 
0.2 | 
0 | 
0.7 | 
| 細砂 | 
4.2 | 
  | 
7.5 | 
0.3 | 
0.2 | 
0.3 | 
  | 
2.5 | 
0.2 | 
7.5 | 
| シルト | 
46.5 | 
  | 
53.7 | 
67.3 | 
71.4 | 
60.2 | 
  | 
59.8 | 
46.5 | 
71.4 | 
| 粘土 | 
48.5 | 
  | 
38.7 | 
32.4 | 
28.4 | 
39.5 | 
  | 
37.5 | 
28.4 | 
48.5 | 
| 中央粒径(μm) | 
4 | 
  | 
8 | 
8 | 
10 | 
6 | 
  | 
7.2 | 
4 | 
10 | 
| N11 | 
礫 | 
2.1 | 
  | 
0.8 | 
3.5 | 
1.9 | 
1.1 | 
  | 
1.9 | 
0.8 | 
3.5 | 
| 粗・中砂 | 
15.3 | 
  | 
6.8 | 
12.4 | 
10.4 | 
9 | 
  | 
10.8 | 
6.8 | 
15.3 | 
| 細砂 | 
62.6 | 
  | 
69.3 | 
52.4 | 
51 | 
51.3 | 
  | 
57.3 | 
51 | 
69.3 | 
| シルト | 
8.5 | 
  | 
3.4 | 
19.3 | 
25.2 | 
17.9 | 
  | 
14.9 | 
3.4 | 
25.2 | 
| 粘土 | 
11.5 | 
  | 
19.7 | 
12.4 | 
11.5 | 
20.7 | 
  | 
15.2 | 
11.5 | 
20.7 | 
| 中央粒径(μm) | 
150 | 
  | 
105 | 
136 | 
126 | 
81 | 
  | 
119.6 | 
81 | 
150 | 
| 9 | 
響灘 | 
H1 | 
礫 | 
17.2 | 
  | 
7.9 | 
0.5 | 
0.4 | 
5.1 | 
  | 
6.2 | 
0.4 | 
17.2 | 
| 粗・中砂 | 
77.8 | 
  | 
13.8 | 
15.2 | 
12.7 | 
26.1 | 
  | 
29.1 | 
12.7 | 
77.8 | 
| 細砂 | 
0.7 | 
  | 
66.1 | 
70.3 | 
70.1 | 
62.7 | 
  | 
54 | 
0.7 | 
70.3 | 
| シルト | 
3.9 | 
  | 
0.3 | 
6.5 | 
8.2 | 
0.1 | 
  | 
3.8 | 
0.1 | 
8.2 | 
| 粘土 | 
0.4 | 
  | 
11.9 | 
7.5 | 
8.6 | 
6 | 
  | 
6.9 | 
0.4 | 
11.9 | 
| 中央粒径(μm) | 
1040 | 
  | 
187 | 
171 | 
169 | 
200 | 
  | 
353.4 | 
169 | 
1040 | 
| H2 | 
礫 | 
1 | 
  | 
0.1 | 
5.8 | 
0.4 | 
0.4 | 
  | 
1.5 | 
0.1 | 
5.8 | 
| 粗・中砂 | 
6.8 | 
  | 
5 | 
19.5 | 
2.4 | 
6.5 | 
  | 
8 | 
2.4 | 
19.5 | 
| 細砂 | 
55 | 
  | 
64.2 | 
51.4 | 
60.2 | 
62.8 | 
  | 
58.7 | 
51.4 | 
64.2 | 
| シルト | 
30.4 | 
  | 
13.4 | 
15.2 | 
17.9 | 
22.5 | 
  | 
19.9 | 
13.4 | 
30.4 | 
| 粘土 | 
6.8 | 
  | 
17.3 | 
8.1 | 
19.1 | 
7.8 | 
  | 
11.8 | 
6.8 | 
19.1 | 
| 中央粒径(μm) | 
130 | 
  | 
125 | 
171 | 
112 | 
123 | 
  | 
132.2 | 
112 | 
171 | 
| H3 | 
礫 | 
  | 
  | 
8.2 | 
0.4 | 
0.4 | 
1.6 | 
  | 
2.7 | 
0.4 | 
8.2 | 
| 粗・中砂 | 
  | 
  | 
17.1 | 
5.8 | 
3 | 
4.1 | 
  | 
7.5 | 
3 | 
17.1 | 
| 細砂 | 
  | 
  | 
65.1 | 
55.4 | 
44.3 | 
51.7 | 
  | 
54.1 | 
44.3 | 
65.1 | 
| シルト | 
  | 
  | 
9.6 | 
23.9 | 
35.4 | 
32.4 | 
  | 
25.3 | 
9.6 | 
35.4 | 
| 粘土 | 
  | 
  | 
0 | 
14.5 | 
16.9 | 
10.2 | 
  | 
10.4 | 
0 | 
16.9 | 
| 中央粒径(μm) | 
  | 
  | 
192 | 
110 | 
47 | 
77 | 
  | 
106.5 | 
47 | 
192 | 
 
注)1.*は中央粒径が4μm未満のもの。平均の算出において、4μmとして算出した。
  2.鹿児島湾(全域)は1980年欠測のため、1981年のデータを引用。
出典)「海洋汚染調査報告」(海上保安庁水路部)
表−2(5) 粒度分布の経年変化   (単位:%)
| No | 
湾名 | 
1980-1 | 
1980-2 | 
1985 | 
1990 | 
1995 | 
1999-1 | 
1999-2 | 
平均 | 
最小 | 
最大 | 
| 10 | 
豊後水道 | 
B1 | 
礫 | 
4.9 | 
  | 
14.9 | 
2.4 | 
2.1 | 
0.6 | 
  | 
5.0 | 
0.6 | 
14.9 | 
| 粗・中砂 | 
90.5 | 
  | 
79.5 | 
80.9 | 
78.5 | 
87.9 | 
  | 
83.5 | 
78.5 | 
90.5 | 
| 細砂 | 
1.3 | 
  | 
1.3 | 
9.7 | 
9.8 | 
9.1 | 
  | 
6.2 | 
1.3 | 
9.8 | 
| シルト | 
1.9 | 
  | 
0.0 | 
1.3 | 
5.0 | 
0.2 | 
  | 
1.7 | 
0.0 | 
5.0 | 
| 粘土 | 
1.4 | 
  | 
4.3 | 
5.7 | 
4.6 | 
2.2 | 
  | 
3.6 | 
1.4 | 
5.7 | 
| 中央粒径(μm) | 
1000 | 
  | 
933 | 
487 | 
444 | 
430 | 
  | 
658.8 | 
430 | 
1000 | 
| B2 | 
礫 | 
0.2 | 
  | 
0.2 | 
0.2 | 
0.1 | 
0.2 | 
  | 
0.2 | 
0.1 | 
0.2 | 
| 粗・中砂 | 
67.2 | 
  | 
34.4 | 
82.7 | 
44.2 | 
38.8 | 
  | 
53.5 | 
34.4 | 
82.7 | 
| 細砂 | 
30.5 | 
  | 
61.3 | 
11.1 | 
45.2 | 
58.3 | 
  | 
41.3 | 
11.1 | 
61.3 | 
| シルト | 
0.8 | 
  | 
4.1 | 
0.3 | 
5.1 | 
0.2 | 
  | 
2.1 | 
0.2 | 
5.1 | 
| 粘土 | 
0.3 | 
  | 
0.0 | 
5.7 | 
5.4 | 
2.5 | 
  | 
2.8 | 
0.0 | 
5.7 | 
| 中央粒径(μm) | 
290 | 
  | 
221 | 
333 | 
229 | 
219 | 
  | 
258.4 | 
219 | 
333 | 
| B3 | 
礫 | 
0.8 | 
  | 
2.7 | 
0.0 | 
1.0 | 
2.0 | 
  | 
1.3 | 
0.0 | 
2.7 | 
| 粗・中砂 | 
77.1 | 
  | 
46.3 | 
88.1 | 
66.4 | 
57.9 | 
  | 
67.2 | 
46.3 | 
88.1 | 
| 細砂 | 
20.7 | 
  | 
46.2 | 
4.5 | 
31.1 | 
37.8 | 
  | 
28.1 | 
4.5 | 
46.2 | 
| シルト | 
1.0 | 
  | 
4.8 | 
2.2 | 
0.7 | 
0.3 | 
  | 
1.8 | 
0.3 | 
4.8 | 
| 粘土 | 
0.4 | 
  | 
0.0 | 
5.2 | 
0.8 | 
2.0 | 
  | 
1.7 | 
0.0 | 
5.2 | 
| 中央粒径(μm) | 
400 | 
  | 
247 | 
419 | 
312 | 
295 | 
  | 
334.6 | 
247 | 
419 | 
| B4 | 
礫 | 
1.3 | 
  | 
2.1 | 
0.9 | 
1.6 | 
0.4 | 
  | 
1.3 | 
0.4 | 
2.1 | 
| 粗・中砂 | 
4.0 | 
  | 
36.8 | 
36.6 | 
32.8 | 
25.4 | 
  | 
27.1 | 
4.0 | 
36.8 | 
| 細砂 | 
55.3 | 
  | 
57.8 | 
55.8 | 
57.4 | 
69.8 | 
  | 
59.2 | 
55.3 | 
69.8 | 
| シルト | 
1.8 | 
  | 
3.3 | 
0.9 | 
2.8 | 
2.5 | 
  | 
2.3 | 
0.9 | 
3.3 | 
| 粘土 | 
2.0 | 
  | 
0.0 | 
5.8 | 
5.4 | 
1.9 | 
  | 
3.0 | 
0.0 | 
5.8 | 
| 中央粒径(μm) | 
230 | 
  | 
220 | 
211 | 
204 | 
183 | 
  | 
209.6 | 
183 | 
230 | 
| 11 | 
鹿児島湾 | 
K1 | 
礫 | 
0.1 | 
  | 
0.6 | 
0.7 | 
0.8 | 
0.2 | 
  | 
0.5 | 
0.1 | 
0.8 | 
| 粗・中砂 | 
7.7 | 
  | 
10.3 | 
14.1 | 
12.2 | 
9.0 | 
  | 
10.7 | 
7.7 | 
14.1 | 
| 細砂 | 
37.6 | 
  | 
35.8 | 
34.0 | 
35.7 | 
30.3 | 
  | 
34.7 | 
30.3 | 
37.6 | 
| シルト | 
31.1 | 
  | 
33.5 | 
32.7 | 
35.8 | 
33.2 | 
  | 
33.3 | 
31.1 | 
35.8 | 
| 粘土 | 
23.5 | 
  | 
19.8 | 
18.5 | 
15.5 | 
27.3 | 
  | 
20.9 | 
15.5 | 
27.3 | 
| 中央粒径(μm) | 
60 | 
  | 
41 | 
58 | 
56 | 
27 | 
  | 
48.4 | 
27 | 
60 | 
| K2 | 
礫 | 
0.1 | 
  | 
1.0 | 
0.0 | 
0.0 | 
2.1 | 
  | 
0.6 | 
0.0 | 
2.1 | 
| 粗・中砂 | 
4.6 | 
  | 
11.4 | 
9.2 | 
4.7 | 
3.6 | 
  | 
6.7 | 
3.6 | 
11.4 | 
| 細砂 | 
14.8 | 
  | 
39.9 | 
29.3 | 
26.4 | 
21.5 | 
  | 
26.4 | 
14.8 | 
39.9 | 
| シルト | 
40.0 | 
  | 
33.8 | 
38.7 | 
42.3 | 
34.5 | 
  | 
37.9 | 
33.8 | 
42.3 | 
| 粘土 | 
40.5 | 
  | 
13.9 | 
22.8 | 
26.6 | 
38.3 | 
  | 
28.4 | 
13.9 | 
40.5 | 
| 中央粒径(μm) | 
15 | 
  | 
69 | 
16 | 
14 | 
9 | 
  | 
24.6 | 
9 | 
69 | 
| K3 | 
礫 | 
0.1 | 
  | 
0.4 | 
0.1 | 
0.0 | 
0.0 | 
  | 
0.1 | 
0.0 | 
0.4 | 
| 粗・中砂 | 
0.7 | 
  | 
0.9 | 
0.5 | 
0.4 | 
1.0 | 
  | 
0.7 | 
0.4 | 
1.0 | 
| 細砂 | 
3.7 | 
  | 
11.5 | 
5.0 | 
5.1 | 
6.4 | 
  | 
6.3 | 
3.7 | 
11.5 | 
| シルト | 
44.5 | 
  | 
47.4 | 
50.6 | 
56.4 | 
46.5 | 
  | 
49.1 | 
44.5 | 
56.4 | 
| 粘土 | 
51.0 | 
  | 
39.8 | 
43.8 | 
38.1 | 
46.1 | 
  | 
43.8 | 
38.1 | 
51.0 | 
| 中央粒径(μm) | 
12 | 
  | 
8 | 
5 | 
6 | 
5 | 
  | 
7.2 | 
5 | 
12 | 
| K4 | 
礫 | 
14.5 | 
  | 
24.7 | 
6.3 | 
22.0 | 
41.4 | 
  | 
21.8 | 
6.3 | 
41.4 | 
| 粗・中砂 | 
29.7 | 
  | 
34.4 | 
20.7 | 
33.9 | 
30.4 | 
  | 
29.8 | 
20.7 | 
34.4 | 
| 細砂 | 
23.4 | 
  | 
21.3 | 
31.5 | 
16.6 | 
11.6 | 
  | 
20.9 | 
11.6 | 
31.5 | 
| シルト | 
19.4 | 
  | 
12.2 | 
26.9 | 
17.7 | 
7.3 | 
  | 
16.7 | 
7.3 | 
26.9 | 
| 粘土 | 
13.0 | 
  | 
7.4 | 
14.6 | 
9.8 | 
9.3 | 
  | 
10.8 | 
7.4 | 
14.6 | 
| 中央粒径(μm) | 
210 | 
  | 
406 | 
104 | 
342 | 
1367 | 
  | 
485.8 | 
104 | 
1367 | 
| 12 | 
若狭湾 | 
W1 | 
礫 | 
0.1 | 
  | 
0.3 | 
0.0 | 
0.2 | 
0.0 | 
  | 
0.1 | 
0.0 | 
0.3 | 
| 粗・中砂 | 
7.3 | 
  | 
6.1 | 
0.7 | 
1.2 | 
0.2 | 
  | 
3.1 | 
0.2 | 
7.3 | 
| 細砂 | 
30.0 | 
  | 
18.2 | 
25.8 | 
19.5 | 
23.1 | 
  | 
23.3 | 
18.2 | 
30.0 | 
| シルト | 
49.1 | 
  | 
55.3 | 
49.5 | 
58.0 | 
36.5 | 
  | 
49.7 | 
36.5 | 
58.0 | 
| 粘土 | 
13.5 | 
  | 
20.1 | 
24.0 | 
21.1 | 
40.2 | 
  | 
23.8 | 
13.5 | 
40.2 | 
| 中央粒径(μm) | 
56 | 
  | 
22 | 
20 | 
24 | 
8 | 
  | 
26.0 | 
8 | 
56 | 
| W2 | 
礫 | 
1.0 | 
  | 
0.9 | 
0.1 | 
0.0 | 
0.6 | 
  | 
0.5 | 
0.0 | 
1.0 | 
| 粗・中砂 | 
28.3 | 
  | 
8.0 | 
1.0 | 
0.6 | 
2.9 | 
  | 
8.2 | 
0.6 | 
28.3 | 
| 細砂 | 
42.3 | 
  | 
41.6 | 
49.5 | 
47.1 | 
50.4 | 
  | 
46.2 | 
41.6 | 
50.4 | 
| シルト | 
20.9 | 
  | 
36.0 | 
38.3 | 
38.3 | 
29.9 | 
  | 
32.7 | 
20.9 | 
38.3 | 
| 粘土 | 
7.5 | 
  | 
13.5 | 
11.1 | 
14.0 | 
16.2 | 
  | 
12.5 | 
7.5 | 
16.2 | 
| 中央粒径(μm) | 
120 | 
  | 
64 | 
64 | 
61 | 
70 | 
  | 
75.8 | 
61 | 
120 | 
| W3 | 
礫 | 
0.5 | 
  | 
1.0 | 
0.3 | 
0.7 | 
2.5 | 
  | 
1.0 | 
0.3 | 
2.5 | 
| 粗・中砂 | 
56.6 | 
  | 
52.4 | 
54.0 | 
40.9 | 
48.3 | 
  | 
50.4 | 
40.9 | 
56.6 | 
| 細砂 | 
26.6 | 
  | 
25.6 | 
24.1 | 
32.1 | 
27.8 | 
  | 
27.2 | 
24.1 | 
32.1 | 
| シルト | 
11.6 | 
  | 
8.7 | 
11.6 | 
16.2 | 
14.3 | 
  | 
12.5 | 
8.7 | 
16.2 | 
| 粘土 | 
3.7 | 
  | 
12.3 | 
9.9 | 
10.1 | 
7.1 | 
  | 
8.6 | 
3.7 | 
12.3 | 
| 中央粒径(μm) | 
290 | 
  | 
269 | 
266 | 
209 | 
254 | 
  | 
257.6 | 
209 | 
290 | 
 
注)1.*は中央粒径が4μm未満のもの。平均の算出において、4μmとして算出した。
  2.鹿児島湾(全域)は1980年欠測のため、1981年のデータを引用。
出典)「海洋汚染調査報告」(海上保安庁水路部)
表−2(6) 粒度分布の経年変化  (単位:%)
| No | 
湾名 | 
1980-1 | 
1980-2 | 
1985 | 
1990 | 
1995 | 
1999-1 | 
1999-2 | 
平均 | 
最小 | 
最大 | 
| 13 | 
富山湾 | 
Y1 | 
礫 | 
0.0 | 
  | 
0.6 | 
0.0 | 
0.0 | 
0.0 | 
  | 
0.1 | 
0.0 | 
0.6 | 
| 粗・中砂 | 
0.5 | 
  | 
0.8 | 
0.5 | 
0.2 | 
0.7 | 
  | 
0.5 | 
0.2 | 
0.8 | 
| 細砂 | 
10.9 | 
  | 
17.7 | 
25.2 | 
1.3 | 
4.8 | 
  | 
12.0 | 
1.3 | 
25.2 | 
| シルト | 
59.4 | 
  | 
61.2 | 
51.6 | 
67.8 | 
63.0 | 
  | 
60.6 | 
51.6 | 
67.8 | 
| 粘土 | 
29.0 | 
  | 
19.7 | 
22.7 | 
30.7 | 
31.5 | 
  | 
26.7 | 
19.7 | 
31.5 | 
| 中央粒径(μm) | 
13 | 
  | 
20 | 
21 | 
9 | 
13 | 
  | 
15.2 | 
9 | 
21 | 
| Y2 | 
礫 | 
0.1 | 
  | 
0.0 | 
0.7 | 
1.3 | 
3.3 | 
  | 
1.1 | 
0.0 | 
3.3 | 
| 粗・中砂 | 
1.2 | 
  | 
0.7 | 
13.1 | 
1.6 | 
8.6 | 
  | 
5.0 | 
0.7 | 
13.1 | 
| 細砂 | 
81.8 | 
  | 
83.4 | 
65.5 | 
80.4 | 
79.2 | 
  | 
78.1 | 
65.5 | 
83.4 | 
| シルト | 
10.9 | 
  | 
8.8 | 
13.5 | 
10.5 | 
6.4 | 
  | 
10.0 | 
6.4 | 
13.5 | 
| 粘土 | 
6.0 | 
  | 
7.1 | 
7.2 | 
6.2 | 
2.5 | 
  | 
5.8 | 
2.5 | 
7.2 | 
| 中央粒径(μm) | 
140 | 
  | 
107 | 
138 | 
102 | 
110 | 
  | 
119.4 | 
102 | 
140 | 
| Y3 | 
礫 | 
0.2 | 
  | 
0.0 | 
0.0 | 
15.9 | 
3.3 | 
  | 
3.9 | 
0.0 | 
15.9 | 
| 粗・中砂 | 
13.2 | 
  | 
3.2 | 
14.3 | 
72.1 | 
2.5 | 
  | 
21.1 | 
2.5 | 
72.1 | 
| 細砂 | 
52.1 | 
  | 
60.2 | 
76.3 | 
8.9 | 
45.3 | 
  | 
48.6 | 
8.9 | 
76.3 | 
| シルト | 
23.0 | 
  | 
24.3 | 
3.1 | 
1.3 | 
30.1 | 
  | 
16.4 | 
1.3 | 
30.1 | 
| 粘土 | 
11.5 | 
  | 
12.3 | 
6.3 | 
1.8 | 
18.8 | 
  | 
10.1 | 
1.8 | 
18.8 | 
| 中央粒径(μm) | 
120 | 
  | 
81 | 
173 | 
690 | 
65 | 
  | 
225.8 | 
65 | 
690 | 
 
注)1.*は中央粒径が4μm未満のもの。平均の算出において、4μmとして算出した。
  2.鹿児島湾(全域)は1980年欠測のため、1981年のデータを引用。
出典)「海洋汚染調査報告」(海上保安庁水路部)