巻号一覧
21 巻 (1980)
- 4 号 p. 181-
- 3 号 p. 119-
- 2 号 p. 51-
- 1 号 p. 1-
21 巻, 2 号
選択された号の論文の6件中1～6を表示しています
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林田 精郎1980 年 21 巻 2 号 p. 51-59
発行日: 1980/06/30
公開日: 2010/02/23
ジャーナル フリーThe ground is always vibrating from the natural and artificial disturbances, it is called a microtremor which measures a few microns in amplitude.
It has been clarified by engineering seismologists that there was a very closed relationship between the earthquake damages and the subsurface structures, and that when the ground was visited by earthquake shocks, the predominant period of the earthquake motion nearly coincides with one of the frequent periods of the microtremor at the respective places.
From the multireflection theory, the microtremor comprises the wave motions magnified by complex multireflection and transmission of the wave within the surface soft layer. Therefore we can estimate the subsurface structures by studying the microtremor.
In this paper, the author reports the results of some theoretical and practical studies on the sounding with the microtremor data and discusses them.抄録全体を表示PDF形式でダウンロード (1079K) -
渡辺 邦夫, 星野 吉昇1980 年 21 巻 2 号 p. 60-70
発行日: 1980/06/30
公開日: 2010/02/23
ジャーナル フリーThe open-cracks in large rock mass play an important role in flowing ground water. The main purpose of this paper is to present the method used to estimate the permeability coefficient of natural open-crack from the distribution of its opening width.
We studied on this problem by following procedures.
(1) The numerical method to describe the approximate flow behaviors in open crack was introduced on the basis of Poiseuille law.
(2) Some permeability coefficients of natural open-cracks were calculated from these distributions of opening width by this method.
(3) These calculated values were compared with the values measured by the permeability test apparatus respectively.
As the result, it was found that the permeability coefficient of natural open-crack can be well estimated by this numerical method.抄録全体を表示PDF形式でダウンロード (1701K) -
河西 秀夫1980 年 21 巻 2 号 p. 71-79
発行日: 1980/06/30
公開日: 2010/02/23
ジャーナル フリーIn August, 1979, a large-scale mudflow occurred at Hora valley near Tochio area of Kamitakara village (Gifu Pref.), then the area suffered from severe disaster.
In this report, inferred causes and conditions of occurrence of mudflow based on the field investigations at the stricken area are described.
At first, geological constitution and their features of Tochio area were reviewed. Secondary, the author attempted to conjecture conditions of running down of the mudflow based on the detail observations of the mudflow deposit. At last, limitation of rainfall condition on occurrence of mudflow was estimated from hydrological data and past record on the typical disaster at the area.
Results obtained from this investigation are as follows:
1) The debris which was produced by collapse of Nohi-rhyolite at the uppermost-reaches of the valley might run down taking deposit of the channel into the flow.
2) A part of the mudflow began to accumulate at the place where valley suddenly broaden, and remaining part of it run down further and accumulated at the lowermost-reaches in Tochio area.
3) Mean velocity of the mudflow was estimated as follows:
In the valley………6.0-6.5m/sec
At the place where valley suddenly broaden……… 4m/sec
At Tochio area………1.6-2.5m/sec
4) Critical precipitation for occurrence of mudflow at the valley was estimated. It is about 30 mm/hour for intensity of effective precipitation.抄録全体を表示PDF形式でダウンロード (2443K) -
重力によるヒマラヤ構造盆地の探査例森林 成生, 丸尾 祐治1980 年 21 巻 2 号 p. 80-87
発行日: 1980/06/30
公開日: 2010/03/25
ジャーナル フリー第四紀の湖成堆積物が厚く堆積するネパール・カトマンズ盆地の基盤地形を明らかにするため重力探査をおこなった。112の点における重力測定から重力異常図を作成し, さらに, 2本の断面における深度計算に基づいて基盤深度図を作成した。
基盤最深部の現在の地表面からの深さは, 650mをややこえる程度と推定される。盆地中央部には, 顕著な基盤の谷状地形が2本検出された。これらの基盤の谷状地形は, 鮮新世～更新世に現在のカトマンズ盆地付近を南南西に流れていたと推定される古バグマティ河 (Hagen, 1968)の化石谷の一部ではないかと考えられる。抄録全体を表示PDF形式でダウンロード (1106K) -
大井 幸雄1980 年 21 巻 2 号 p. 88-97
発行日: 1980/06/30
公開日: 2010/02/23
ジャーナル フリーThere exist some layers of earth, found principally in Japan's cities, which react with and absorb oxygen in the air, Workers have died of asphyxiation when excavating these strata.
An effective way of preventing this kind of accident is to check before operations begin whether or not the area has been analyzed for oxygen absorbing layers.
The reason for this phenomena lies in the chemical properties of the soil.
This report demonstrates that the presence or absence of oxygen absorption soil can be determined by following chemical tests on soil samples to be taken during geological surveys:
1. Test for redox potential
2. pH test
3. Detremination of oxygen absorption by the Buret method
4. Analysis of ferrous and sulfur ions
In addition, the report shows that in those cases where the taking of samples is difficult, analysis of the oxygen content of gas that escapes from the borehole during gas permeability testing is also effective.抄録全体を表示PDF形式でダウンロード (1531K) -
本荘 静光1980 年 21 巻 2 号 p. 98-100
発行日: 1980/06/30
公開日: 2010/02/23
ジャーナル フリーPDF形式でダウンロード (321K)
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