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八木 健三
原稿種別: 論説
1959 年 3 巻 2 号 p.
63-75
発行日: 1959/02/20
公開日: 2018/01/15
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Average compositions of various kinds of Cenozoic alkalic rocks found in Japan and the surrounding areas are calculated from some 220 chemical analyses, and are compared with the average compositions of alkalic rocks from the Intra-Pacific region. In the mineralogical composition, it is worthy of notice that kaersutite, which has been regarded as a rare mineral, is frequently found in the present region, and that leucite-bearing rocks, though insignificant in amount, are also found in some localities. Frequency of the rock types in the two regions is calculated from the number of chemical analyses employed. Two maxima of basalt and rhyolite are noticed in Japanese region, while no maxima of rhyolite is found in Intra-Pacific region' and in its stead small maximum of trachyte is found, beside a prominent maximum of basalt. This relation is also confirmed by the close study of some typical petrographic provinces in the Japanese region. Predominance of rhyolite in some localities is remarkable. Chemically the alkalic rocks of the present region as a whole are richer in potash than the corresponding rocks in the Intra-Pacific region. From these petrochemical features it is concluded that the parental magma of the alkalic rocks of the present region is primarily different from that of the Intra-Pacific alkalic rocks. Some of the alkalic rocks in the present region are produced by the crystallization differentiation of the parental magma, but others are difficult to be explained by this process. Here contamination of granitic crust might have played an important role in their formation. From the enomous amount of rhyolitic rocks in some provinces of the present region, it is suggested that at least some of them might have been produced by the selective refusion of granitic crust, which was rather rich in potash.
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島津 康男
原稿種別: 論説
1959 年 3 巻 2 号 p.
76-94
発行日: 1959/02/20
公開日: 2018/01/15
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A physical aspect of magmatic differentiation process is quantitatively studied. A relation between physical conditions and variations of crystal composition during the differentiation is our main interests. A continuous reaction series of binary system is studied and the results obtained are applied to olivine and plagioclase. The discussion is reduced to solve a diffusion equation with a moving crystal-melt interface. The moving velocity of interface or the apparent growth rate depends upon a freezing rate, a convection velocity within melts, and a gravitational sinking velocity of crystals. Figures 8~11 represent variations of crystal composition for various physical conditions. The apparent growth rate is estimated as 10
-6〜10
-4 cm/day for the gabbro intrusion in Skaergaard, Greenland. A convection in a sill-type intrusion is also studied. The natural conditions seem to be unfavourable for the convection. A horizontal temperature gradient in dyke-type intrusion tends the apparent diffusivity of melts to increase and it destroys the convection. The zoning structure of plagioclase is assumed to be due to a rapid change of freezing rate and is quanitatively analyzed.
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山崎 正男
原稿種別: 論説
1959 年 3 巻 2 号 p.
95-106
発行日: 1959/02/20
公開日: 2018/01/15
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Eruptions of pyroclastic fall, pyroclastic flow, and lava (lava flow, lava dome, lava spine) often take place together in a single cycle of volcanic eruption. Probable genetical relations between these three kinds of eruptions are schematically shown in Fig. 1. An intense vesiculation of magma within the vent would throw pyroclastic materials high above the crater causing a pyroclastic fall eruption. A less intense vesiculation within the vent would generate an eruption of pyroclastic flow. Probably the water content of magma is smaller in this latter case than in the preceding one. A delay of vesiculation of a highly viscous magma may cause a nuee ardente eruption in the strict sense. A magma, still poorer in water, may cause no explosive vesiculation either within the vent or after leaving the crater. It will only cause a calm extrusion of lava. The water content of magma in the gravitational field is greater in the higher level of the magma column. Magmas erupted in earlier phases of an eruption woule represent the higher level of the column. Hence they will cause pyroclastic fall eruptions. In later phases of the same eruption, the water content of magma would decrease. Hence, pyroclastic flows and lava flows would be formed successively. The magmas may become poor in water in later phases, partly because of the esecape of water during earlier phases of the eruption. The order of successive events in seventeen historic and prehistoric eruptions manifested by fifteen volcanoes of the world is given in Table 1. The actual order of eruption is in harmony with the above consideration. In many calderas the volume of mass collapsed is found to be greater than that of the erupted materials. This question has never been furnished with a reasonable explanation. The writer proposes a hypothesis that the volume difference between the collapsed mass and the erupted materials corresponds to the volume of water dissolved in the magma prior to the eruption.
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諏訪 彰, 田中 康裕
原稿種別: 論説
1959 年 3 巻 2 号 p.
107-118
発行日: 1959/02/20
公開日: 2018/01/15
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The temperature inside the fissures of the lave at the scores of the permanent observation points in the summit crater of Miharayama have been measured at the definite interval of time by the staff of the Oshima Weather Station with a thermocouple or a mercury-in-glass thermometer since the beginning of August, 1952. The writers have analysed the data of the measurements made during the period from 1952 to 1957, and have attempted to study the relation between the changes in the temperature of the grounds in the crater and the surface volcanic activities and the volcanic earthquakes and tremors that occurred during the announced period. With regard to the changes in the temperatures of the fumaroles at the observation points, 5 different types are notified, as designated by A, B, B', C, D. Of these, B-type change is of great significance from the volcanological viewpoint. The points, where such temperature change was observed, are located in the zone running through the pits active during these years and in the marginal zone of the circular central sink, nearly coinciding with the former central pit in the summit crater. Particular changes in temperature as referred to above may certainly be caused by increase in the underground activity or shallow intrusion of magma. Therefore, systematic temperature measurements of the ground may be useful in the prediction of the eruptive activities of the volcano.
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水谷 義彦, 松尾 禎士
原稿種別: 論説
1959 年 3 巻 2 号 p.
119-127
発行日: 1959/02/20
公開日: 2018/01/15
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The aim of this research is focused on the following two points: 1) To examine whether the constancy of the chemical composition of fumarolic gas is established or not in a short period (10-20 hrs.). 2) To examine the feasibility of chemical forecast of volcanic eruption by knowing the chemical behavior of fumarolic gases in calm periods of a volcano. Sampling of condensed water and measurement of temperature and relative flow rate were made 24 times at the intervals of 1 hr. at a fumarole of Volcano Showa-shinzan on 17th. August, 1958. Chemical components analysed are pH, Cl
-, F
-, NO
3-, SO
4-, B, Na
+, K
+, Mg
++, and Ca
++. The results obtained are: 1) Little time variation of the temperature of fumarolic gas is observed (653±2℃). 2) About ±5% fluctuations are found for the concentration of Cl
-, F
-, and B in the “normal” samples. The Cl:F:B ratio is almost constant in these samples, viz., Cl:F:B = 37:9.3:1 (wt. ratio). 3) “Abnormal” samples are classified into the following three types, (1) KCl contamination (2) KNO
3 contamination (3) dilution with water vapor. (1) and (2) are due to the abrupt feeds of KCl and KNO
3 to the fumarolic gas separatedly. Almost all of the abnormal samples are followed by the increase of SO
4-- and the decrease of F
-. We cannot explain the ultimate cause of the occurrence of abnormal samples.
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清野 政明
原稿種別: 論説
1959 年 3 巻 2 号 p.
128-135
発行日: 1959/02/20
公開日: 2018/01/15
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In this paper, geophysical studies were made on the heat source for the fumaroles taking as the signs of the interior state the physical properties of gases emitted therefrom. The temperature, density, velocity, etc. of the emitted gas from the fumaroles were measured at Showa-Shinzan, Tarumae and Me’akandake, in Hokkaido, the results being given in Table 1. The gases are in general consisting of over 90% water vapour. The gas is therefore regarded tentatively as water vapour. The results of study are concluded as follows: 1) The temperature at the “Kamenokoiwa”-fumarole, may be the highest in the Showa-Shinzan area, is found as has been falling down with time (Fig. 3). Based on the time variation of temperature obtained above, the mass of the heat source which supplies the fumarole with heat was estimated, assuming that the emission of the gas is nearly stationary and that the heat is transferred merely by the emissive gas, i.e water vapour. The mass of the source thus estimated is 2.3 × 10
7 tons, for which is substituted a spherical rock mass of density 2.5 with radius of about 130m (Fig. 4). The figure given above may designate the lower limit for heat source of Showa-Shinzan, since it was estimated on the assumption that the heat was transferred through only one fumarole. 2) Extensive application of the above consideration may lead to the estimation of the initial water content W of the source as follows: W = c
skt/(cg+c
skt’) where k, c
s and c
g are time-temperture coefficient, specific heat of the heat source and the gas respectively, and t is the time elapsed since the gas is emitted from the fumarole. By using the above formule, we can calculate the value of W, wherefrom it is thought probable that the water vapour emitted from the “Kamenokoiwa”-fumarole may contain not only juvenile but also underground circulating water. The same reasoning may be applicable to the cases of the other fumaroles, when the time-temperature relation of gases therefrom are known. 3) At the fumarole, situated on the dome-side of Tarumae, the statical pressure of the emissive gas was obtained as 38 atm. This value is comparable to the pressures of explosions at times of histrical eruptions of this volcano (Table 2).
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種子田 定勝, 松本 征夫, 宮地 貞憲, 宮地 六美, 石橋 澄, 児島 正憲
原稿種別: 論説
1959 年 3 巻 2 号 p.
136-146
発行日: 1959/02/20
公開日: 2018/01/15
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An explosion occurred suddenly at Nakadake crater of Aso volcano at 22h 15m, June 24, 1958. The blow and ejecta gushed southwestwards and broke down many houses situated at about 1000m from the crater. The initial velocity of the ejecta is estimated to be 100m/s and their amount about 380,000ton. The explosive energy is therefore about 10
19 erg. Most of the ejected materials are fragments of various size derived from the crater filling tuff and lava blocks. Rarely lava fragments, origin of which may be essential or accessory, are found. The ejecta was hot enough so that the temperature measured was over 50℃ even in the ash at the place 1000m from the crater. The mechanical composition revealed by histogram and cumulative curve designates that the ejected material is of an intermediate character between ash fall and pumice flow.
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吉川 宗治, 狐崎 長琅
原稿種別: 論説
1959 年 3 巻 2 号 p.
147-153
発行日: 1959/02/20
公開日: 2018/01/15
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Short period micro-tremors were observed at the volcano Aso for a month from the beginning of July, after the eruption on 24th June 1958. The observations were made with the moving coil type seismometric pick-ups which are connected directly to galvanometers, the free oscillation frequencies being 2 and 30 cycles respectively. The observing points were distributed in the area within 1km from the active crater. The velocities as well as directions of propagation of the volcanic micro-tremors were obtained by tripartite observations. The frequency-distribution of periods was deduced from the analysis of the results of the same tripartite observations. The results obtained are; 1. The predominant periods of the volcanic micro-tremors are 0.25sec. at Hondo and the Volcano Museum and 0.2sec. at Sunasenri. 2. The propagating velocities of the volcanic micro-tremors at Hondo and the Volcano Museum are 1.5-4.0km/sec., while 0.5-3.0km/sec. at Sunasenri. 3. The origin of micro-tremors deduced from the rate of variations in propagating velocities near crater must be as deep as 700-900m. from the surface. 4. The predominant direction of oscillation of the volcanic micro-tremors is perpendicular to that of the propagation.
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G. S. GORSHKOV
原稿種別: Article
1959 年 3 巻 2 号 p.
154-156
発行日: 1959/02/20
公開日: 2018/01/15
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G. S. GORSHKOV, I. I. TOVAROVA
原稿種別: Article
1959 年 3 巻 2 号 p.
157-158
発行日: 1959/02/20
公開日: 2018/01/15
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八木 健三, 松本 幡郎
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
159-
発行日: 1959/02/20
公開日: 2018/01/15
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竹下 寿
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
159-
発行日: 1959/02/20
公開日: 2018/01/15
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谷田 勝俊
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
159-160
発行日: 1959/02/20
公開日: 2018/01/15
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河野 義礼, 青木 謙一郎
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
160-
発行日: 1959/02/20
公開日: 2018/01/15
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勝井 義雄
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
160-161
発行日: 1959/02/20
公開日: 2018/01/15
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山崎 正男
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
161-
発行日: 1959/02/20
公開日: 2018/01/15
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牛来 正夫
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
161-
発行日: 1959/02/20
公開日: 2018/01/15
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竹山 一郎, 田中 康裕, 山口 弘次
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
161-162
発行日: 1959/02/20
公開日: 2018/01/15
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島 通保
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
162-
発行日: 1959/02/20
公開日: 2018/01/15
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下鶴 大輔, 後藤 賢一, 中牟田 修, 野田 博治
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
162-163
発行日: 1959/02/20
公開日: 2018/01/15
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吉川 宗治, 狐崎 長琅
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
163-
発行日: 1959/02/20
公開日: 2018/01/15
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吉川 宗治, 加茂 幸介, 狐崎 長琅
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
163-
発行日: 1959/02/20
公開日: 2018/01/15
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岩崎 岩次, 桂 敬, 小沢 竹二郎, 吉田 稔, 鎌田 政明, 松本 幡郎
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
163-
発行日: 1959/02/20
公開日: 2018/01/15
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岩崎 岩次, 小沢 竹二郎, 吉田 稔, 松本 幡郎, 田中 省三, 鎌田 政明
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
163-164
発行日: 1959/02/20
公開日: 2018/01/15
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松本 幡郎
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
164-
発行日: 1959/02/20
公開日: 2018/01/15
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松本 幡郎
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
164-
発行日: 1959/02/20
公開日: 2018/01/15
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鎌田 政明, 小沢 竹二郎
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
164-
発行日: 1959/02/20
公開日: 2018/01/15
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岩崎 岩次, 小沢 竹二郎, 平山 光衞
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
164-165
発行日: 1959/02/20
公開日: 2018/01/15
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岩崎 岩次, 小沢 竹二郎, 平山 光衞, 吉田 稔
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
165-
発行日: 1959/02/20
公開日: 2018/01/15
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岩崎 岩次, 小沢 竹二郎, 平山 光衞, 鎌田 政明
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
165-
発行日: 1959/02/20
公開日: 2018/01/15
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鎌田 政明
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
165-166
発行日: 1959/02/20
公開日: 2018/01/15
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桂 敬, 秋本 俊一, 久城 育夫
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
166-
発行日: 1959/02/20
公開日: 2018/01/15
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岩崎 岩次, 桂 敬, 真島 美智雄, 原村 寛, 吉田 稔, 才野 浩, 岸岡 昭
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
166-
発行日: 1959/02/20
公開日: 2018/01/15
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山本 敬
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
166-167
発行日: 1959/02/20
公開日: 2018/01/15
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松尾 禎士, 水谷 義彦, 鈴置 哲朗, 杉山 邦夫
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
167-
発行日: 1959/02/20
公開日: 2018/01/15
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野口 喜三雄, 神谷 宏, 中山 弘
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
167-168
発行日: 1959/02/20
公開日: 2018/01/15
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野口 喜三雄, 神谷 宏, 中山 弘
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
168-
発行日: 1959/02/20
公開日: 2018/01/15
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山口 鎌次
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
168-
発行日: 1959/02/20
公開日: 2018/01/15
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安井 豊
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
169-
発行日: 1959/02/20
公開日: 2018/01/15
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木沢 綏
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
169-
発行日: 1959/02/20
公開日: 2018/01/15
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関谷 溥
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
169-170
発行日: 1959/02/20
公開日: 2018/01/15
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清野 政明
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
170-
発行日: 1959/02/20
公開日: 2018/01/15
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村瀬 勉
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
170-
発行日: 1959/02/20
公開日: 2018/01/15
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下鶴 大輔
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
170-171
発行日: 1959/02/20
公開日: 2018/01/15
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茂木 清夫
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
171-
発行日: 1959/02/20
公開日: 2018/01/15
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島津 康男
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
171-172
発行日: 1959/02/20
公開日: 2018/01/15
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横山 泉, 音田 功
原稿種別: 講演要旨
1959 年 3 巻 2 号 p.
172-
発行日: 1959/02/20
公開日: 2018/01/15
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