著者

河角 広

出版者

東京大学地震研究所

雑誌

東京大学地震研究所彙報 (ISSN:00408972)

巻号頁・発行日

vol.29, no.3, pp.469-482, 1951-09

被引用文献数

6

著者

河角 広

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.79, no.3, pp.115-138, 1970-06-25 (Released:2009-11-12)

被引用文献数

7 13

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In earlier days most Japanese wanted eagerly to have means of earthquake prediction in order to escape earthquake disaster taking refuge in advance in open spaces since they were almost powerless in encountering the menaces. We are now enabled to long for the mitigation of the disaster by the advancement of science and technology, although we have not yet succeeded to predict the coming of a disastrous earthquake. Our safety thus depend entirely on our effort for the countermeasures against the calamity. But we have only limited allowances for such preparations economically and in time available. It is therefore inevitable to start the preparation from the most important and imminent localities in a country, from the national point of view.In Japan, according to the writer's witness on the imminence of Southern Kwanto District at the Diet in July, 1964, such preparation work for Tokyo Metropolis was started the next month by a new Earthquake Division of the Disaster Prevention Council of the Metropolis, and several important hazard possibilities of the imminent earthquake have been revealed with the result that similar committees have also been made in other prefectures and cities in the same area as well as in the Central Government of the country.In this paper the writer intended to give the ground for his assertion of the imminence of a disastrous earthquake giving proofs of the periodicity of such calamities on the statistical and historical analyses, and made some comments on the possible consequences and major problems in the countermeasures to cope with the conceived disaster as revealed by the studies made on the national and metropolitan levels.In view of the importance, interest and the space allowance, only the proofs of the periodicity in the recurrence of destructive earthquakes in the district concerned are summarised in this abstract.Historical earthquakes in and around Kwanto District as shown in the map (Fig. 2.1) were examined and those which were destructive at Kamakura or presumable as such from the standard intensity-distance-magnitude curve were selected and listed in Table 1.1. Periodicities of these earthquakes were analysed statistically. Similar analyses were also applied to the earthquakes experienced in Tokyo which are listed in Table 2.2. A definite period τ of 69 years (besides a few integral multiples of this period) was clearly found. The methods used in the above analyses were by means of (1) Fourier transforms (Fig. 1.1), (2) autocorrelation functions (Figs. 1.3 and 1.4) and (3) historical examinations of the number of cases when no destructive earthquakes took place within the standard deviation +√ ξ2 from the year tp when a destructive earthquake was expected to occur from the periodicity. Test of persistence of the period was also made by means of the theory of random walks consisting of Fourier amplitudes in successive periods (Figs. 1.5 a and b). Rayleigh-Schuster's criterion (Formula 1.3) that is the probability of obtaining the actual Fourier amplitude on the assumption of no periodicity or the resultant distance of above mentioned random walks gave the values of the probability equal to 0.06% and 0.03% for Kamakura and Tokyo respectively. In comparison to usual value of 5 or 10% for recognizing periodicity in geophysical phenomena, the smallness of the above values is more than enough to disprove the non-existence of the periodicity of 69 years in the recurrence of destructive earthquakes in the districts under consideration.

著者

河角 広 佐藤 泰夫

出版者

東京帝國大学地震研究所

雑誌

地震研究所研究速報

巻号頁・発行日

no.5, pp.1-35, 1947-04-15

---

昭和21年12月21日南海大地震調査報告(第1報)

著者

河角 広

出版者

日本建築学会

雑誌

建築雑誌 (ISSN:00038555)

巻号頁・発行日

no.799, 1953-06

著者

佐山 守 河角 広

出版者

東京大学地震研究所

雑誌

地震研究所研究速報

巻号頁・発行日

vol.10, no.2, pp.1-50, 1973-03

著者

佐山 守 河角 広

出版者

東京大学地震研究所

雑誌

地震研究所研究速報

巻号頁・発行日

vol.10, no.2, pp.1-50, 1973-03

---

When a big earthquake occurs, the en quete method through post cards is usually carried out for the inverstigation of intensity distribution and damage and their relations to the ground conditions and geology. Thus collected data isalsousefulforthe prevention of damage due to big earthquakes. This method can be applied to large historical earthquakes when abundant historical documents are found. As the first step of the application of on qttete method to historical earthquakes, the Zenkoji earthquake which occurred at about 10 p.m. on the 24th of March, 1847 was studied.

著者

河角 広

出版者

東京大学地震研究所

雑誌

東京大學地震研究所彙報 (ISSN:00408972)

巻号頁・発行日

vol.30, no.4, pp.319-323, 1952-01-30

著者

河角 広

出版者

東京大学地震研究所

雑誌

東京大學地震研究所彙報 (ISSN:00408972)

巻号頁・発行日

vol.30, no.4, pp.325-330, 1952-01-30

著者

河角 広 佐藤 泰夫

出版者

東京帝國大学地震研究所

雑誌

地震研究所研究速報

巻号頁・発行日

vol.5, pp.1-35, 1947-04-15

---

昭和21年12月21日南海大地震調査報告(第1報)

著者

高橋 竜太郎 河角 広 竹山 謙三郎 金井 清 武藤 清

出版者

一般社団法人日本建築学会

雑誌

建築雑誌. 研究年報

巻号頁・発行日

vol.60, pp.139-140, 1960-07-18

著者

河角 広

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.79, no.3, pp.115-138, 1970

被引用文献数

13

---

In earlier days most Japanese wanted eagerly to have means of earthquake prediction in order to escape earthquake disaster taking refuge in advance in open spaces since they were almost powerless in encountering the menaces. We are now enabled to long for the mitigation of the disaster by the advancement of science and technology, although we have not yet succeeded to predict the coming of a disastrous earthquake. Our safety thus depend entirely on our effort for the countermeasures against the calamity. But we have only limited allowances for such preparations economically and in time available. It is therefore inevitable to start the preparation from the most important and imminent localities in a country, from the national point of view.<BR>In Japan, according to the writer's witness on the imminence of Southern Kwanto District at the Diet in July, 1964, such preparation work for Tokyo Metropolis was started the next month by a new Earthquake Division of the Disaster Prevention Council of the Metropolis, and several important hazard possibilities of the imminent earthquake have been revealed with the result that similar committees have also been made in other prefectures and cities in the same area as well as in the Central Government of the country.<BR>In this paper the writer intended to give the ground for his assertion of the imminence of a disastrous earthquake giving proofs of the periodicity of such calamities on the statistical and historical analyses, and made some comments on the possible consequences and major problems in the countermeasures to cope with the conceived disaster as revealed by the studies made on the national and metropolitan levels.<BR>In view of the importance, interest and the space allowance, only the proofs of the periodicity in the recurrence of destructive earthquakes in the district concerned are summarised in this abstract.<BR>Historical earthquakes in and around Kwanto District as shown in the map (Fig. 2.1) were examined and those which were destructive at Kamakura or presumable as such from the standard intensity-distance-magnitude curve were selected and listed in Table 1.1. Periodicities of these earthquakes were analysed statistically. Similar analyses were also applied to the earthquakes experienced in Tokyo which are listed in Table 2.2. A definite period τ of 69 years (besides a few integral multiples of this period) was clearly found. The methods used in the above analyses were by means of (1) Fourier transforms (Fig. 1.1), (2) autocorrelation functions (Figs. 1.3 and 1.4) and (3) historical examinations of the number of cases when no destructive earthquakes took place within the standard deviation +√ ξ<SUP>2</SUP> from the year t<SUB>p</SUB> when a destructive earthquake was expected to occur from the periodicity. Test of persistence of the period was also made by means of the theory of random walks consisting of Fourier amplitudes in successive periods (Figs. 1.5 a and b). Rayleigh-Schuster's criterion (Formula 1.3) that is the probability of obtaining the actual Fourier amplitude on the assumption of no periodicity or the resultant distance of above mentioned random walks gave the values of the probability equal to 0.06% and 0.03% for Kamakura and Tokyo respectively. In comparison to usual value of 5 or 10% for recognizing periodicity in geophysical phenomena, the smallness of the above values is more than enough to disprove the non-existence of the periodicity of 69 years in the recurrence of destructive earthquakes in the districts under consideration.

著者

河角 広

出版者

公益社団法人地盤工学会

雑誌

土と基礎 (ISSN:00413798)

巻号頁・発行日

vol.19, no.8, pp.34-40, 1971-08-25