Population Changes and Natural Disasters in the Tohoku Region Since the Latter Half of the Nineteenth Century

From 1895 to 1935, the population increase rate of the Tohoku Region was almost equaled that of Japan as a whole. Since then, except for 1940–1945, when Japan was greatly affected by the war, the population increase rate of the Tohoku Region never exceeded that of Japan as a whole, and the population ratio of the Tohoku Region compared to the national has continued to decline. Since 1995, the population growth rate of the Tohoku Region entered a phase of decrease. This chapter divides the period from 1885 to 2020 into several time periods and examines the effects of natural disasters on long-term population change in the Tohoku Region from the perspective of the two demographic transition processes. In 1896, the year of the Meiji Sanriku Tsunami, the crude death rate in the Tohoku Region was 3.73‰ higher than the national rate; this disparity was the largest throughout the period under study. The main reason for the emigration of about 240,000 people across the Tohoku Region between 1905 and 1909 is thought to have been the successive bad harvests and the resulting increase in the number of people moving to Hokkaido. At the beginning of the Showa Era, the Tohoku Region once again suffered from a series of bad harvests. Furthermore, in 1933, the region experienced the Showa Sanriku Tsunami. As in the Meiji Era, the bad harvest had a greater impact on people’s demographic behavior. Regarding the postwar period, the differences in fertility and mortality fluctuations between Japan as a whole and the Tohoku Region can be summarized as follows: (1) Time lag at the end of the first fertility transition, (2) absence of a second baby boom in the Tohoku Region, (3) time lag of the second fertility transition, and (4) time lag of the transition to a natural population decrease. In the Tohoku Region, the mobility transition entered a new phase when the cohort born between 1970 and 1975 reached their 20s (i.e., the 1990s). This is the stage at which the U-turn phenomenon was no longer observed, and the Tohoku Region entered a stage of “irreversible exodus of the younger generation” up to their 30s. The Tohoku Region experienced the Great East Japan Earthquake Disaster at a time when this mobility transition was in full swing.