Vesiculation and Calcium Hydrosulfate Crystals in Volcanic Ashes From Sakurajima Volcano and their Environmental effects

樱岛火山的火山灰可分为三大类：黑灰、火山灰。例如，最常见的火山灰;红色灰烬的特征是高含量的氧化铁，存在方石英、石膏和硬石膏;白色灰烬的特征是大量的气孔状火山玻璃颗粒。在普通火山灰中存在泡状火山玻璃颗粒和硫酸氢钙晶体，这是因为火山灰在喷发时经历了绝热膨胀，并在火山气体的作用下发生了某些化学反应。火山灰组成物质的物质性质和粒度的物理因素以及火山气体的化学因素，讨论了农产品、火山灰及其伴生的火山气体所产生的物理和化学因素，影响着人类健康和泥石流，火山灰微粒填充表皮气孔，导致呼吸停止或功能减退的物理因素和火山气体遇水呈酸性的化学因素的复合因素。与此同时，当人类每天继续吸入大量的火山灰时，在不久的将来，人类肯定会出现呼吸道疾病，如矽肺或尘肺病和/或类似疾病。火山灰本身的特性与泥石流的成因有着密切的关系。樱岛火山有十八条干涸的河流。即使是小雨，由于火山灰本身的物理化学特性，干涸的河流也经常在下游引起大规模的泥石流。

Volcanic ashes from Sakurajima Volcano can be grouped into three major classes : black ashes, i. e., most common volcanic ashes ; red ashes characterized by the high-content of ferric iron oxide and the presence of cristobalite, gypsum and anhybrite ; and white ashes characterized by abundant grains of vesiculated volcanic glass. The presence of grains of volcanic glass in the vesiculation state and that of crystals of calcium hydrosulfate in common volcanic ashes are significant in that volcanic ashes were subjected to the adiabatic expansion, and to some chemical reaction due to volcanic gases at the time of eruption.The natural and social environments are affected by two major factors due to volcanic ashes and their accompanying volcanic gases ; physical factors attributed to the substantial nature and grain size of volcanic ash-composing materials, and chemical factors to volcanic gases.Discussions were given to mechanisms that farm products, human health and debris flows are effected by the physical and chemical factors due to volcanic ashes and their accompanying volcanic gases.Farm products are resulted into killing down by a composite factor of the physical factor that volcanic ash-micrograins fill epidermal stomata and, as a result, respiration is stopped or hypofunction takes place, and the chemical factor that volcanic gases behave as acids when they are encountered with water. Meantime, when man continues to inspire a considerable amount of volcanic ash every day, man showing respiratory diseases such as silicosis or pneumoconiosis and/or their similar diseases, will surely come out in not so far future. A close relationship is demonstrated between characteristics of volcanic ash itself and the cause of debris flows. There are eighteen dry rivers at Sakurajima Volcano. Even if it is light rain, dry rivers very often cause a big scale of debris flow down-stream due to physicochemical features of volcanic ash itself.