Volcanoes In Japan Research Articles

Studies on the Volcanoes in Japan The CaO/(Na2O+K2O):FeO/MgO in the volcanic rocks

The writer examined the relations between the chemical and mineral compositions of Japanese volcanic rocks., The difference between "pyroxene andesites" (rocks carrying no hornblende as phenocrysts) and "hornblende andesites" (all the rocks carrying hornblende as phenocrysts) is shown most clearly by the diagram in which the ordinate gives the ratio CaO/Na2O+K2O) and the abscissa FeO/MgO., In this diagram the former rocks all into an area with higher CaO/(Na2O+K2O) and FeO/MgO ratios, and the latter ones into an area with lower ratios, the two areas being bounded by a curve corresponding to {CaO/(Na2O+K2O)}×(FeO/MgO)=K (const., ) approximately., Moreover basic members of the pyroxene andesites tend to lie away from the boundary curve while acidic ones near the curve., The two areas are designated as "hornblende field" and the "pyroxene field"., The position of the boundary curve is not fixed, being variable in different provinces or volcanoes (Ref., Fig., 1-Fig., 7)., For example, when CaO/(Na2O+K2O)=FeO/MgO, √(K)is 1., 7 for Iizuna and Kurohime volcanoes, 1., 3 for Kayagatake volcano, 1., 1 for Asama volcano, etc., ., This figure may be used as an index showing chemical characteristics of each volcanoes or petrographic provinces., The writer proposes to call √(K)"the CaO/(Na2O+K2O):FeO/MgO Index (in short CaO·Alkalies·FeO·MgO) Index".,

Studies on volcanoes in Japan

Studies on volcanoes in Japan

Additional Remarks to "Studies on the Volcanoes in Japan, : The Spreading of the Activity"

In his previous paper, ("Studies on the volcanoes in Japan - The spreading of the activity" in this Journal, 1948) the writer pointed out that the volcanic activity in Japan spread towards N from S, but in another paper (Jour., Jap., Assoc, Petrol., Min., & Eco., Geol., XXXII, 1944) he had stated that the most volcanoes in Japan had a tendency that the centre of activity (eruption) migrated from W∼N to E∼S., It is apparently incompatible, but these two facts may be interpretated without self-contradiction as follows: 1) The activity in a period of volcanic action of Japan spreads towards N from the initial point of the action., 2) The point of action in a later period migrates towards E from that in the earlier period., 3) Sequently, at a volcano with an active line (fissure) in the E-W direction the centre of eruption migrates towards E from W through the history of the volcanic action, and at a volcano with an active line in the N∼W - S∼E direction it migrates toward S∼E.,

Observations on the formation of surfaces of slip in mild steel, in metals, and in natural rocks

The mechanical conditions under which solids can deform permanently without fracturing are of interest to engineers, metallurgists, and, in some applications, to geologists. The ductile metals are the most widely used artificial materials of construction. It is natural, therefore, that their mechanical properties have been widely investigated by engineers and metallurgists. Among these metals soft steel shows the peculiarity that when it is deformed to a small degree fine markings of an astonishingly regular pattern appear on the surface of the deformed test‐piece. These fine patterns frequently accompany the first plastic deformations after the yield‐point has been reached in steel. They are traces of thin layers in which the metal has been deformed locally. The description and geometry of these surfaces of slip has opened up broad theoretical approaches to a mechanics of the plastic states of stress in steel. In minerals and in rocks, on the other hand, many evidences of permanent deformation are known to the geologist. A description of the plastic distortion observable in the strata of rocks is one of the fundamental problems of geology. The conditions encountered in the deeper sedimentary or igneous rocks—the prevailing of small differences of stress, of elevated temperatures increasing with the depth, of high average pressures—are important factors contributing to plastic flow. Changes in the structure of rocks are known which are frequently very similar to those which have been observed in plastically deformed metals. A number of observations of this kind were shown in examples of which a large number have not been yet reported in publications. The flow‐patterns were demonstrated in the following examples: Compression of prismatic steel pieces; compression of paraffin cylinders; flow‐lines starting near a small hole in bodies deformed by compression; a case of this type in meteoric iron. In an extruded tube of clay beautiful markings were discovered through an accidental fracture of the tube, disclosing the flow‐pattern in the tube wall which had been influenced through the friction along the tube surface. Square and rectangular plates were deformed by means of a concentrated load while the plates were resting along their circumference. Again beautiful very regular flow‐patterns appeared on the surface of these plates. If a steel block, the surface of which has been polished, is deformed by a concentrated pressure, for example, if the pressure is exerted by means of a cylindrical punch, beautiful slip‐lines appear around the impression consisting of two systems of logarithmic spirals. Reference was made to observations in Japan in which it was claimed that the secondary cones on one of the volcanoes in Japan appear to be distributed along similar logarithmic spirals which would indicate a radial symmetry of the stress‐field. In a motion‐picture film several examples of the propagation of the plastic zone and of the formation of surfaces of slip were demonstrated in tension‐tests and in bending tests with plates.

Studies on volcanoes in Japan (I)

Studies on volcanoes in Japan (I)

Erratum to : Geochemical Investigations of Volcanoes in Japan. XXIII

Erratum to : Geochemical Investigations of Volcanoes in Japan. XXIII

Volume and Area of Volcanoes in Japan Proper

Volume and Area of Volcanoes in Japan Proper

Geochemical Investigations of Volcanoes in Japan. XXIII

Geochemical Investigations of Volcanoes in Japan. XXIII

Geochemical Investigations of Volcanoes in Japan. XXII

淺間火山の主として長野縣側に於ける約130個の觀測點に於て湧水及び河水の水温並にpHを測定した結果1)水温湧泉並に噴氣孔の温度分布を一括すれば噴氣孔では車坂噴氣孔の67.0°が最も高温で,前掛山噴氣孔45.0°が之に次ぐ,湧泉では小瀬温泉の40.0°が最も高く,星野温泉37.7°が之に次いで温度が高い.温度分布を見るに車坂噴氣孔,前掛山噴氣孔は淺間山,小淺間山,車坂山,高峰山を結ぶ直線上に位し,淺間山麓に於ては星野温泉,干ケ瀧温泉,小瀬温泉等の地方及び湯の瀬,大笹鑛泉の附近が温度が高い.蛇掘川,濁川流域の湧水は悉く低温である.最も低温なるは杉瓜,鳥居原の井戸で7.5°である.又之等諸種湧水の温度變化を檢するに地獄谷湧水を除いては其變化は多くて1～2°程度であつた.2)湧水のpH地獄谷噴氣孔溜水側湧水III(pH1.2)は最も酸性強く,最もアルカリ性の湧水は三笠温泉(pH8.2)である.一般に湧水は山頂に近いものほど酸性度高く,夫より海面上高が低下するに從ひ酸性度低下し谷底に於ては中性又は弱アルカリ性となる.又淺間山附近諸種湧水のpH變化を檢するに地獄谷湧水を除いては其變化は極めて少く多くて0.1～0.3程度であつた.3)河水のpH萬座川の水はpH 4.3で最も酸性高く,其他の河水は何れも中性又は弱アルカリ性である.河水のpHは一般に水源地に於ては酸性度高く流下するに從ひ酸性度低下し中性又は弱アルカリ性となる.

Geochemical Investigations of Volcanoes in Japan. XX

Geochemical Investigations of Volcanoes in Japan. XX

Geochemical Investigations of Volcanoes in Japan. XXI

Geochemical Investigations of Volcanoes in Japan. XXI

Geochemical Investigations of Volcanoes in Japan. XIX

彌彦,角田附近の鑛泉約20箇所のラドン含有量を測定した結果,鑛泉のラドン含有量は湧出口附近の地質的環境によりて異り,火山岩の地方のもめには水成岩の地方のものより著しく多いことが認められる.

Geochemical Investigations of Volcanoes in Japan. XVII

Geochemical Investigations of Volcanoes in Japan. XVII

Geochemical Investigations of Volcanoes in Japan. XVIII

火山淺間山々麓に湧出する多くの温泉及び鑛泉に就いての柴田雄次教授,野口喜三雄氏,金子修氏の研究により岩漿水は地表水より多く輕い水素竝びに酸素の同位元素を含むことが推論せられた.著者は火山焼岳の頂上の噴氣孔から噴出する高温の水蒸氣を凝縮し,又焼岳山麓の温泉及び鑛泉より各種の水を採集し此等と東京市水道水との比重差を測定せる結果,温泉水には上述の柴田學説が當嵌まるが噴氣孔水蒸氣は豫想に反し非常に重いことを知つた.

Geochemical Investigations of Volcanoes in Japan. XIV

Geochemical Investigations of Volcanoes in Japan. XIV

Geochemical Investigations of Volcanoes in Japan. XIII

Geochemical Investigations of Volcanoes in Japan. XIII

Geochemical Investigations of Volcanoes in Japan. XV

Geochemical Investigations of Volcanoes in Japan. XV

Geochemical Investigations of Volcanoes in Japan. XII

Geochemical Investigations of Volcanoes in Japan. XII

Geochemical Investigation of Volcanoes in Japan. XVI

Geochemical Investigation of Volcanoes in Japan. XVI

Geochemical Investigations of Volcanoes in Japan. XI

Geochemical Investigations of Volcanoes in Japan. XI