著者

和達 清夫 中曽根 康弘

雑誌

情報処理

巻号頁・発行日

vol.1, no.1, 1960-07-30

著者

和達 清夫

出版者

公益社団法人 日本地震学会

雑誌

地震 第2輯 (ISSN:00371114)

巻号頁・発行日

vol.34, no.special, pp.180-184, 1981-09-25 (Released:2010-11-17)

被引用文献数

1

著者

和達 清夫

出版者

Meteorological Society of Japan

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

vol.3, no.8, pp.201-211, 1925-09-18 (Released:2009-02-05)

被引用文献数

1 1

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Some seismograms of the destructive earthquake occurred on May 23rd, 1925 in North Tazima district, show distinctly so-called the Mohorovi_??_i_??_ wave _??_. One of them is shown in Fig. (4) magnified from the seismograms of Wiechert's 200kg. seismograph installed at the Central Meteorological Observatory in Tokyo. (Epicenter distance about 450km.)The author of the present paper has drawn the hodograph for the longitudinal wave P from the results of seismic observations of the meteorological stations in this country as well as the time difference between P and _??_ from seismograms of these stations in case when it revealed on it. Moreover the curve of _??_ is also drawn on the same diagram and is shown in Fig. (6).Nextly, the author has assumed that, to interprete the time curve the discontinuity layer exists not so far from the surface in the earth crust. Following numerical values are obtained:-Velocity of the longitudinal waveabove the discontinuity layer, v1=5.56km. per see.Ditto under the discontinuity layer, v2=7.50km. per see.Epicenter distance of stations where Pand _??_ waves arrive simultaneously Δ0-120km.Difference of T(P)-T(_??_), shown in Fig. (6) is 6.2 sec.From these values, the depth of the discontinuity layer and that of the seismic foeus of this earthquake is determined. He has also compared the time of occurrence with those of the other two great earthquakes which have occurred on Jan. 15th, 1924 and Sept. 1st, 1923 respectively in Fig. (1); and ascertained that the geographical effect is not so great in these time-curves that the following conclusion may hold good in its main figure, even in any earthquake which occurred everywhere in this country.Followings are main results obtained in this paper:-(1) So called “initial movement” takes place with sudden change in its magnitude, and sometimes in direction, at the place about 100-200km. distant from the epicenter. Fig. (5).(2) The epicenter distance above mentioned depends chiefly upon the depth of seismic focus, therefore the depth may be estimated by this means. (3) I_??_itial movement must be very weak at the stations which lie within the epicenter distance, from 200km. to 1000km. approximately.(4) For the determination of the direction of epicenter from that of the initial movement of longitudinal wave, it is better to use _??_ phase than P and this will be done with much accuracy and easiness. (5) Depth of the discontinuity layer and that of the focus of Tazima-earthquakes are calculated and their values have been found to be about 42km. and 32km. respectively.(6) S-phase of the transverse wave begin to appear gradually o_??_ seismogram and with increasing epicenter distance it becomes more distinct.(7) Irregular form of isochronal curves may be considered as the effect of the discontinuity layer whose depth may not be definite in a part of the earth-crust of this part of the globe.(8) Well known “Omori's formula” which expresses the relation between the duration of preliminary tremor and epicenter distance, may hold good with _??_ and _??_ phases for the region of small epicenter distance and with P and L phases at distant places.The present paper is a preliminary report and the more complete studies will follow in a near future.

著者

和達 清夫

出版者

公益社団法人 日本気象学会

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

vol.5, no.6, pp.119-145, 1927

被引用文献数

10

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地震の震源の深さに就いては從來種々の結果が得られて居るが、近來近地地震觀測の精密さに依り震源の深さは殆んど總ての地震に就き四十粁内外が最も普通となされて居る。我が國に起る多くの地震に就きても、多くの研究は悉くこの程度の淺き震源の深さを與へて居る。而るに著者は或種の地震を研究したる結果、其れ等が三百粁以上の深き震源を有すべき結論に達し、假りに之を深層地震と呼ぶ事にした。此の結論が正しければ、從來の地震源捜索法に改良を要し、又過去の地震表の訂正を要することゝなる。依うて本論文に於て其の決論の達したる研究を述べて學會の批判を仰がんと欲す。多くの集蒐されたる深層地震中特に大正十五年七月廿七日の地震は、本州中央部の地下約三百五十粁の深さに發現したる代表的の深層地震なりと考へらるゝを以て、其の記象型及び震波の走時に關し詳細の調査がなされて居る。本論文に於ては右研究の結果として、地震源の深さ及び地殼上層に於ける震波の傳播速度が求められた。<br>かゝる深層地震の存在は近地地震の觀測に依り地殼上層の物理的状況の研究をなすのに極めて好都合の材料を與ふるものである。近年の觀測に於て確に深層地震であると決定されるものを求め其等の分布から深層地震帶なるものが求められた。この深層地震帶は從來の地震帶と略直角に交叉し從來のものと別にある新しい意味を持つ地震帯であり、其の地震帶附近に於て近來の大地震が發現して居るのも興昧ある事である。此の地震帶に就いても大體の調査がなされて居るが、淺き大地震と深層地震との間に何等かの關係が認められさうである。此の問題は大地震の警戒に關し實際的に興味ある問題を與へるものと思はれる。

著者

和達清夫著

出版者

中央氣象臺附属測候技術官養成所

巻号頁・発行日

1929

著者

和達清夫 柿内賢信 森脇大五郎監修

出版者

教育出版

巻号頁・発行日

0000

著者

和達清夫著

出版者

朝日新聞社

巻号頁・発行日

1949

著者

和達清夫 [ほか] 著

出版者

出版者不明

巻号頁・発行日

0000

著者

和達 清夫

出版者

公益社団法人 日本地震学会

雑誌

地震 第2輯 (ISSN:00371114)

巻号頁・発行日

vol.34, pp.180-184, 1981

被引用文献数

1

著者

和達 清夫 益田 クニモ

出版者

公益社団法人 日本気象学会

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

vol.10, no.12, pp.670-675, 1932

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To see the general state of the seismic activity in the Kwant&ocirc;-district, where is noted by the frequent occurrence of earthquakes and especially by the Great Earthquake of Kwant&ocirc; (Sept. 1, 1923), North Idu (Nov. 26, 1930) and West Saitama (Sept. 21, 1931), the large earthquakes occurred in this district during the last 9 years are investigated about the position of their origins particularly taking account of the depth of focus.

著者

和達 清夫

出版者

東京帝国大学地震研究所

雑誌

東京帝國大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, Tokyo Imperial University (ISSN:00408972)

巻号頁・発行日

no.1, pp.55-58, 1926-10-15

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application/pdf

著者

和達 清夫

出版者

水利科学研究所

雑誌

水利科学 (ISSN:00394858)

巻号頁・発行日

vol.7, no.4, 1963-10

著者

和達 清夫

出版者

資源協会

雑誌

資源 (ISSN:03872300)

巻号頁・発行日

no.14, pp.9-15, 1953-11

著者

和達 清夫 鷺坂 清信 益田 クニモ

出版者

公益社団法人 日本気象学会

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

vol.10, no.8, pp.460-474, 1932

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It has been generally known that earthquakes take place at any depth in the crust as far as about 500km. below the surface. For the investigation of near earthquakes, a standard table of travel time of seismic waves transmitted from the origin of variable depths is required to be made by the recent materials obtained in the seismometrical observation. For this purpose, the time-distance curve of the great earthquake occurred in North Idu district on Nov. 26, 1930 is adopted and the values of seismic wave velocity calculated by Mr. Honda are used in this paper. Thus, several tables of the travel time concerning the depth of focus and the epicentral distance are obtained. They are considered to be applicable for various branches of our practical seismology. Further, we have also calculated a table of the correction due to the depth of focus which must be applied on the travel time at a large epicentral distance in the case of distant earthquakes. As for further investigations of seismic wave propagation based upon the present tables, we shall write in the next report.

著者

和達 清夫

出版者

新潟大学積雪地域災害研究センター

雑誌

新潟大学積雪地域災害研究センター研究年報 (ISSN:03877892)

巻号頁・発行日

no.3, pp.149-157, 1981-11

著者

和達 清夫

出版者

公益社団法人 日本気象学会

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

vol.4, no.4, pp.86-91, 1926

著者

和達 清夫

出版者

公益社団法人 日本気象学会

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

vol.3, no.8, pp.201-211, 1925

被引用文献数

1

---

Some seismograms of the destructive earthquake occurred on May 23rd, 1925 in North Tazima district, show distinctly so-called the Mohorovi_??_i_??_ wave _??_. One of them is shown in Fig. (4) magnified from the seismograms of Wiechert's 200kg. seismograph installed at the Central Meteorological Observatory in Tokyo. (Epicenter distance about 450km.)<br>The author of the present paper has drawn the hodograph for the longitudinal wave P from the results of seismic observations of the meteorological stations in this country as well as the time difference between P and _??_ from seismograms of these stations in case when it revealed on it. Moreover the curve of _??_ is also drawn on the same diagram and is shown in Fig. (6).<br>Nextly, the author has assumed that, to interprete the time curve the discontinuity layer exists not so far from the surface in the earth crust. Following numerical values are obtained:-<br>Velocity of the longitudinal wave<br>above the discontinuity layer, <i>v</i>₁=5.56km. per see.<br>Ditto under the discontinuity layer, <i>v</i>₂=7.50km. per see.<br>Epicenter distance of stations where P<br>and _??_ waves arrive simultaneously &Delta;₀-120km.<br>Difference of T(P)-T(_??_), shown in Fig. (6) is 6.2 sec.<br>From these values, the depth of the discontinuity layer and that of the seismic foeus of this earthquake is determined. He has also compared the time of occurrence with those of the other two great earthquakes which have occurred on Jan. 15th, 1924 and Sept. 1st, 1923 respectively in Fig. (1); and ascertained that the geographical effect is not so great in these time-curves that the following conclusion may hold good in its main figure, even in any earthquake which occurred everywhere in this country.<br>Followings are main results obtained in this paper:-<br>(1) So called &ldquo;initial movement&rdquo; takes place with sudden change in its magnitude, and sometimes in direction, at the place about 100-200km. distant from the epicenter. Fig. (5).<br>(2) The epicenter distance above mentioned depends chiefly upon the depth of seismic focus, therefore the depth may be estimated by this means. <br>(3) I_??_itial movement must be very weak at the stations which lie within the epicenter distance, from 200km. to 1000km. approximately.<br>(4) For the determination of the direction of epicenter from that of the initial movement of longitudinal wave, it is better to use _??_ phase than P and this will be done with much accuracy and easiness. <br>(5) Depth of the discontinuity layer and that of the focus of Tazima-earthquakes are calculated and their values have been found to be about 42km. and 32km. respectively.<br>(6) S-phase of the transverse wave begin to appear gradually o_??_ seismogram and with increasing epicenter distance it becomes more distinct.<br>(7) Irregular form of isochronal curves may be considered as the effect of the discontinuity layer whose depth may not be definite in a part of the earth-crust of this part of the globe.<br>(8) Well known &ldquo;Omori's formula&rdquo; which expresses the relation between the duration of preliminary tremor and epicenter distance, may hold good with _??_ and _??_ phases for the region of small epicenter distance and with P and L phases at distant places.<br>The present paper is a preliminary report and the more complete studies will follow in a near future.

著者

和達 清夫

出版者

公益社団法人 日本気象学会

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

vol.10, no.7, pp.397-401, 1932

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In this paper, is treated a simple geometrical method for locating the position of earthquake focus by the arrival times of initial phase observed in the seismograms of several stations near the epicenter. The propagating velocity of seismic waves is assumed to be constant everywhere in the crust, but some considerations are also made in the case that the velocity increases with the depth.

著者

和達 清夫

出版者

公益社団法人 日本気象学会

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

vol.6, no.1, pp.1-43, 1928

被引用文献数

2

著者

保柳 睦美 内藤 誉三郎 和達 清夫 伏見 康治 矢澤 大二

出版者

公益社団法人 東京地学協会

雑誌

地學雜誌 (ISSN:0022135X)

巻号頁・発行日

vol.89, no.1, pp.71-77, 1980