This paper attempts to delimit the spheres of intra-migration area and examine the intra-migration structure in the Tokyo metropolitan area. The data of O-D matrix, used in this paper, are gathered by the report of the 1990 population census of Japan.
By factor analysis of the 259×259 OD matrix, 44 factors with eigenvalues of not less than 1.0 were extracted to account for 83.2% of the total variance. On the basis of factor loadings (≥0.5) and factor scores (≥1.5), the 259 unit areas were grouped into 35 nodal areas, and the first 12 factors were interpreted as follows: (1) Chiba area (16.4%), (2) Oomiya area (7.9%), (3) Setagaya area (7.1%), (4) Matudo area (5.5%), (5) Yokohama area (4.5%), (6) Suginami area (3.9%), (7) Kawagoe area (3.0%), (8) Koutou area (2.9%), (9) Itabasi area (2.7%), (10) Kasukabe area (2.2%), (11) Kumagaya area (2.1%) and (12) Odawara area (1.8%).
The results of the analysis are summarized as follows.
(1) Migration areas of the Tokyo metropolitan area are classified into the 3 type: core type, sector type and outskirt type.
(2) About half of migration in the Tokyo metropolitan area are explained by the sector type.
(3) Sector type migration areas are distributed along the main railway network.
(4) In the outskirt of the Tokyo metropolitan area, the rate of in migration is high at the districts along main railway network.
(5) In the core type migration area, the direction of migration is complex. In the sector type migration area, the direction of migration extends to the outskirt of Tokyo metropolitan area. In the outskirt type migration area, the direction of migration extends from the large suburbun city to the neighboring city.