都市水害論(1)-災害の時空間スケールと変遷について-

Abstract

As my short notes of natural water hazards, historical changes in the waterhazards and their prediction are summarized in a series of the natural water hazardsin urban areas.In the first report, change in total population for a period of past about 10, 000years shows five stages in its change, and then the time and spatial scales in natu-ral water hazards are introduced to consider historical changes in the hazards. Theyare classified into longer and shorter timescales and their relevant spatial ones. Bythe longer timescale, natural hazards for a period of past about 10, 000 years are con-sidered in relation to changes in natural forces such as solar activity, temperature, sea level and vegetation, and in social environment such as residence, productionand social activities. By the shorter time scale, natural water hazards and theirchanges in a period of past 2, 000 years are also considered in more detail in relationto natural forces such as climate change, typhoons, drought and plagues, and socialenvironment such as reclamation, construction, internal wars, social activities andpolitics.