| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2003: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2002: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Research Abstract |
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.
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