The process of population migration in the United States can be simply summarized as follows:1In the middle of the 9th century, the first civil war led to population migration to the west; The second time,/kloc-at the turn of the 9 th century and the 20 th century, with industrialization and urbanization, the population flowed from rural areas to cities; The third time, in the 1920s and 1940s, due to the agricultural crisis and natural disasters, the southern population migrated to the north and west.

For the fourth time since 1950s, the population of the old industrial areas in Northeast China moved to the sunshine zone of new resources and new industries in the south and west. The trend of population migration is from northeast to west and south. The eastern and northern regions are dominated by emigrants, and the emigrants always outnumber the immigrants.

cause analysis

Due to the rise of the third scientific and technological revolution, textiles, steel, coal and shipbuilding have all become traditional industrial sectors, and their competitiveness has gradually lost. The output value of American traditional industries accounts for about 1/4 of GDP. Generally speaking, the proportion of employees in traditional industries in the United States is declining. In order to improve its position in the market, traditional industrial departments make use of the new achievements of the third scientific and technological revolution.

Introducing advanced technology, self-improvement and transformation in order to seek longer-term development, from labor-intensive to capital and technology-intensive, labor productivity has increased rapidly. As a result, the labor force needed by traditional industrial sectors is getting less and less, and the relatively surplus labor force is greatly increased, thus providing conditions for the large-scale migration of the American population.