Many kinds of substances (solids and volatiles) have been discharged by volcanic phenomena such as volcanic eruption, fumarolic activity and hot-spring activity. Usually the amounts of volcanic products have been estimated only by measuring the amounts of residual solid products after volcanic eruptions. However, they are not the total amounts of volcanic products, because they have not contained the tremendous amounts of volcanic gases discharged at volcanic eruptions. Then, in this paper, the method for the determination of volatile components of volcanic products discharged by volcanic action are proposed. Relation between amounts of heat energy and amounts of chloride ion discharged from hot springs in Japan is estimated to be about Cl=10^-8 ton/Kcal (Iwasaki et al 1963). The total amount of chloride ion discharged from hot springs in Japan is estimated by this relation to be 9.3x10¹¹ g/yr, which is very near the calculated value 8x10¹¹ g/yr obtained from water discharge and the average content of chloride of hot springs in Japan.

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Infrared airbon surveys have been made on the Nishinoshima volcnao of Ogasawara Islands and its surrounding sea surface, on January 13, 1974 by “Nishihnoshima Research Group”. The submarine eruptions near Nishinoshima have been initiated from April 1973. On December 21, the new volcano has grown to an island larger than the old Nishinoshima. This island is about 700 m long, 250 m wide and about 50 m hight above sea level. This volcanic island was named Nishinoshima-shinto which means a new Nishinoshima. On January 13, 1974, two cinder-cones have been formed at the eastern and western parts of the new island. Volcanic activities were limitted to the eastern cinder-cone. The red hot lava was seen in the crater and lava was flowing out from the flank. Small eruptions of Strombolian type with 50～100 m high cinder ejections have been observed at intervals of one to two minutes. Thermal measurments were made by the “Infrared line-scanor Model DEI-1200” having an InSb sensor. A filter from 4.5 to 5.5μ wave length was employed and three different flight levels 300 m, 450 m, and 900 m were employed. In order to determine the thermal feature of the active crater, sea surface and volcanic island, we employed three temperature regions such as “high”, “low” and “intermediate” ones.

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Near the west rim of the Aso caldera, Aso-2 pyroclastic flow deposit, one of the four major eruption-cycle deposits erupted from the Aso area before the formation of present Aso caldera, is devided into Aso-2R, -2A and -2B subunits in ascending order. In this area, Aso-2A is densely welded to the very base of the deposit and adheres to the surface of the underlying Aso-2R unit without basal non- or partially- welded zone (Figs. 2, 3, 4). Some parts of Aso-2A deposit have evidence of secondary flowage by its extremely flattened essential lenses which are elongated in a direction on the foliation plane showing flow lineation (Figs. 5, 6, 7, 9). Aso-2R is homogeneous, lava-like deposit of pyroclastic origin formed by coalescence and homogenization of vitric shards accompanied by mass movement of viscous laminar flow. Various kinds of relict pyroclastic or vitroclastic structures and textures are found in Aso-2R in the field and under the microscope (Figs. 10-16). At Loc. 10 in Fig. 1 the basal face of Aso-2R shows "ropy surface" like pahoehoe lava surface indicating a certain amount of laminar flowage (Fig. 17), while at Loc. 1 Aso-2R has differentiated into scoriaceous top, central compact and massive or platy part and breceiated base, like those of a typical aa lava flow (Figs. 2 and 3) suggesting much longer traval distance of laminar flow which may exceeds 100 meters and may well be called rheoignimbrite defined by Rittmann (1962).

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Pyroclastic flows from Kujfi volcano are divided into two stages. Both are pumice flows. In them, only the former (Handa pumice flow) is welded. The latter (Senomoto pumice flow) contains lithic volcanic blocks in the upper part. The former is intercalated between Aso-3 and Aso-4, and Aso-4 is, in turn, overlain by the latter. Both are similar in petrography and chemistry. The former is distributed further than 20 km distance from possible source area, but its exposed volume is small by the cover of later deposits and by erosion. The letter covers wide area in the south side of Kuju volcano and is large in volume.

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