Flowage process and behavior of magmatic water of long lava flows from fuji volcano.

本文对富士火山猿桥和三岛熔岩流的流动过程进行了研究。猿桥熔岩沿狭窄的V形河谷流下，大部分由一个绳状熔岩流单元组成。但在两个地方，支流加入熔岩流下的山谷，发现熔岩由几个流动单元组成，其中一些小规模的帕霍霍瓣被水冷却。这些产状被解释为受支流河水的淬火作用而形成，而另一部分则被膨胀成厚的单一流动单元，并不保留膨胀前形成的小规模帕霍霍瓣的原始形状。另一方面，三岛熔岩由三个以上的流动单元组成，每个流动单元都是厚度小于2米的薄层流。在山顶附近，形成了一个管道系统，岩浆似乎很快就被供给了，但在下游一侧，岩浆无法充分膨胀，岩浆从岩浆岩席叶中流出，并以薄片的形式扩散。与猿桥熔岩从狭窄的V形山谷中流下不同，三岛熔岩是在宽阔的平原上流下的，因此它是水平扩散的，不能垂直膨胀。为了比较紫菜中的含水量，计划对这些紫菜采用卡尔-费休滴定法进行分析。本项目确定了玄武岩样品分析的条件：1）将样品粉碎后，在150℃下加热24小时以上，称重;然后除去吸收的水。2）随后，将样品加热1000℃，并分析溶解在玻璃中的水。期望岩石样品被粉碎得比100微米更细。

Two of the long lava flows from Fuji volcano, Saruhashi and Mishima laves were investigated for their flowage process from their occurrences. Saruhashi lava flowed down through a narrow V-shape valley and is composed of one pahoehoe flow unit in most part. But in two localities where the tributaries join the valley through which the lava flowed down, it is found that the lava consists of several flow units, with small-scale pahoehoe lobes some of them being chilled by water. These occurrences are interpreted to be-formed by quenching effect by the river water from the tributaries, whereas, the other portion was inflated to be thick single flow unit and did not reserve the original shape of small-scale pahoehoe lobes which was formed before inflation. On the other hand, Mishima lava consists of more than three flow units each of which is thin sheet flow less than 2 meter thick. Near the summit, a tube system was developed and magma seems to have been supplied quickly but in the downstream side, magma could not inflate enough and magma drained out from the precursory sheet lobe and spread as thin sheets. In contrast to that the Saruhashi lava flowed down through the narrow V-shaped valley, the Mishima lava flowed down in a wide flat plain, therefore, it spread horizontally and could not inflate vertically. In order to compare the water contents in the laves, the _analyses by Karl-Fisher titlation method was planned for these laves. In this project, the conditions for the analyses of basaltic rock samples were obtained as follows : 1)crushed sample is heated by 150℃ for more than 24 hours, and the weight is measured. Then the absorbed water is removed. 2)Subsequently, the sample is heated by 1000℃ and the water dissolved in the glass is analyzed. It is desirable that the rock sample is crushed finer than 100 micron.