著者

松浦 律子 田力 正好

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.71, pp.103-116, 2018-07-10 (Released:2018-08-09)

参考文献数

30

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After the Russo-Japanese War, too little information about earthquakes was published by the Central Meteorological Observatory, and it has made us left in difficulty to examine earthquakes of the Taisho era precisely. Among such earthquakes, the M5.7 destructive earthquake on August 6th, 1916, in Ehime Prefecture was re-examined by the excavated same age documents. Irazu weather station and other stations, which were operated by the company of Besshi copper mine, reported the detail of this earthquake. Identification of reported places about cracks and falling rocks was done, in addition to the examination of the seismic intensity distribution left in newspapers and the Official Gazette. It is proposed to move the epicenter of this earthquake to (33.95°N, 133.4°E), where is six-km south from that in Utsu-catalogue, and closer to the Ishizuchi fault, which belongs to the Median Tectonic Line active fault zone. It is also found that this event has a felt foreshock a half day before, and a felt aftershock an hour later. This event is the first candidate of destructive earthquakes of the MTL active fault zone in the written history.

著者

永峰 康一郎 榊原 淳一 杉崎 隆一

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.42, no.2, pp.211-217, 1989-06-24 (Released:2010-03-11)

参考文献数

8

被引用文献数

2 1

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A computer-based system for automatic seismo-geochemical observations has been developed. At Hoshina hot spring, Nagano city, as a monitoring station, a personal computer regulates observation instruments such as gas chromatograph and water flow-meter, and it records the data on its floppy disks. In this study, the data transmission with a simplified telemetry system was improved. Through a public communication line and MNP modems, the data are sent to a personal computer in our laboratory. The modem enables us to transfer the data reliably without troubles caused by noise and phase delay, because it contains the function for correcting the error during correspondence. The simple BASIC program can be easily revised for expansion of measurement instruments. In view of cost, size and simplicity, this processing system is applicable for continuous on-site measurements for seismo-geochemistry.

著者

石橋 克彦

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.72, pp.69-89, 2019 (Released:2020-01-31)

参考文献数

92

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In leap July of the 5th year of Bunroku (in the old Japanese calendar; mostly September, 1596 in the Gregorian calendar) Bungo province (present-day Oita Prefecture) in Kyushu, southwest Japan, suffered from severe earthquake and tsunami disasters. Concerning the occurrence date of the causative earthquake, the prevailing idea is currently that a large earthquake took place on leap July 9 (September 1, 1596) in Iyo province (present-day Ehime Prefecture) in Shikoku, on the eastward opposite shore of Bungo, and another large earthquake occurred on leap July 12 in Bungo. Against this idea, I claim that a single event which can be called “the Iyo-Bungo earthquake” occurred around seven p.m. on leap July 9 in the Iyo-Bungo region based on reliable contemporary historical records. There are 69 documents on this (these) earthquake(s) printed in the existing collections of historical earthquake materials, but their values as historical records vary considerably. Since the essential principle of historiographical seismology is to utilize only reliable first-grade documents, I performed historical source criticism to select 16 contemporary materials. I referred to their original or best texts, not using texts printed in the collections. According to a record in Bungo violent ground motion collapsed shrine buildings around seven to nine p.m. on leap July 9 and a large tsunami hit Fuchu (Oita) in the twilight. In Kyoto, an autograph diary of a court noble, which is used for the first time in historical seismology, describes considerable earthquake motion around seven p.m. on leap July 9. In Hiroshima Prefecture, at Hatsuka-ichi and Itsukushima strong ground motions were felt at night on leap July 9 without damages, and at Mihara strong tremors continued from leap July 9 till 12. In Iyo, a contemporary record says a severe ground motion occurred on leap July 9 and the whole Iyo province had trouble, suggesting earthquake damages in a wide area. In Satsuma and Osumi provinces (present-day Kagoshima Prefecture), a record tells a strong earthquake on leap July 9. As a fundamental methodology of historiographical seismology, these tremors and tsunami in Bungo, Iyo, Kyoto, Hiroshima and Kagoshima on leap July 9 are considered to have been produced by an identical earthquake unless there is any counter-evidence. Leap July 12, the other proposed date of the Bungo earthquake, comes from historical materials written after 1698, which probably mistook the great Kyoto earthquake in the midnight of leap July 12 for the Bungo event. Seismic intensities are estimated to be 6 in Bungo, stronger than or equal to 5 in Iyo, 4 in Hiroshima Prefecture, 3 in Kyoto, and about 4 in Kagoshima on the JMA scale (1949-1996 version). The most simple and reasonable interpretation is that a large earthquake with the source region from around Beppu Bay off Bungo to the offshore area of western Iyo, a part of the Median Tectonic Line fault zone, took place around seven p.m. on leap July 9, whose inferred magnitude being about 7.5 (corresponding to MJMA), and the tsunami on the Bungo coast followed.

著者

束田 進也

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.61, no.Supplement, pp.575-589, 2009-07-31 (Released:2013-11-21)

参考文献数

46

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Japan is a seismically active country, and earthquake information is indispensable in Japan. There are various systems or aspects concerning earthquake information, such as earthquake observations on scientific basis, real-time seismic data processing systems, dissemination systems of the results of processed data as earthquake information, and citizens’ understandings and utilization of the information. If the above mentioned whole flow can be called a “mechanism”, Japan is the only one that has the unique and advanced “mechanism” on earthquake information in the world. This mechanism, that can also be called one of the Japanese cultures, has not been built up in a reasonable way from the beginning but it took very long time in establishing the current mechanism. In addition, a new earthquake information provision service has been started that has the nature of earthquake forecast, not observation. Like this, the character of the mechanism has been changing. In this paper, the current Japanese earthquake information is outlined, and its issues are also described.

著者

澁谷 拓郎 平原 和朗 上野 友岳

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.61, no.Supplement, pp.199-207, 2009-07-31 (Released:2013-11-21)

参考文献数

38

被引用文献数

2

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Receiver function analyses have been developed since the late 1970s. Receiver functions are calculated by deconvolving the vertical component from the horizontal components of teleseismic P waveforms in order to remove the complexities of the source time functions and to extract the structural information beneath seismic stations. The receiver functions are sensitive to impedance discontinuities of the earth’s interior, especially to the shear wave velocity discontinuities. Therefore, the receiver function analyses have advantages in estimating the shear wave velocity structure and imaging the shear wave velocity discontinuities. In this paper we introduce several basic topics of the receiver function analyses. Firstly, we discuss the method of the calculation of the receiver functions, pointing out weaknesses in the water level method and the multitaper method and introducing the extended-time multitaper method. Secondly, we describe the inversions of the receiver functions for the shear wave velocity structure. We show two examples with the genetic algorithm. Thirdly, we introduce the way and several examples to image the shear wave velocity discontinuities with the use of the receiver functions. Finally, we discuss issues in the receiver function analyses which have not been addressed yet but should be in the near future.

著者

池上 良平

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.20, no.4, pp.174-177, 1968-01-30 (Released:2010-11-17)

被引用文献数

1

著者

飯田 汲事

出版者

公益社団法人 日本地震学会

雑誌

地震 第1輯 (ISSN:00371114)

巻号頁・発行日

vol.12, no.1, pp.6-14, 1940-01-25 (Released:2010-11-17)

参考文献数

19

著者

多田 堯 飯田 汲事

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.25, no.4, pp.295-301, 1973-03-30 (Released:2010-03-11)

参考文献数

13

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The relationships between the predominant period and the magnitude of the microearthquakes were studied. We assume the relationship in the following form. LogT=a+bM where, T is the predominant period in second and M is the earthquake magnitude. The following results were obtained, LogT=-1.50+0.50M (P wave, microearthquakes occurred in the vicinity of the Neo-Valley) LogT=-1.12+0.45M (S wave, microearthquakes occurred in the vicinity of the Neo-Valley) LogT=-1.38+0.44M (P wave, microearthquakes occurred in the vicinity of the Inuyama City) LogT=-2.03+0.65M (P wave, Matsushiro earthquake swarm) LogT=-1.45+0.40M (whole P wave). From the dislocation theory, the relation of T and M is derived as follows, LogT=-0.3-0.7 Logσ+0.5M. (1) where, σ is the stress drop in bar. Substituting σ=40 bars into (1), we get LogT=-1.4+0.5M. (2) This equation agrees well with the above mentioned results. But, when σ is not constant, the equation (1) suggests that the difference of the predominant period in the same earthquake magnitude is the differences of the stress drop. Indeed, the deviations of the data are so large that the stress drops seem to be not constant.The predominant periods of the Matsushiro earthquake swarm are shoter than those of the other microearthquakes. This evidence may relate to the characteristics of the Matsushiro earthquake swarm.

著者

飯田 汲事 坂部 和夫

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.25, no.1, pp.44-55, 1972-07-30 (Released:2010-03-09)

参考文献数

8

被引用文献数

3

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The western extension of the Fuk6zu fault associated with the Mikawa earthquake in 1945 was investigated by the present geological survey. It was ascertained that the extension of the fault has begun near the pass between the villages, Kiriyama and Miyabasama and has been followed as far as Shikoyamachi, Nishio city, a total distance of about 9km. As the result of this survey a total length of the earthquake fault formed by the Mikawa earthquake in 1945 became about 28km as shown in Fig. 3. The fault is of a reverse type, and it has manifested itself as a northeastward upthrusting of the land on the southwest side of the fault amounting up to about 1.8m.The fault also may presumably continue to the northwest and further to the Nobi earthquake fault which was formed in 1891, based on the seismological standpoint. It is concluded that a number of destructive earthquakes in the past might occur in connection with a chain of faults such as the Fukui, the Nobi, and the Mikawa earthquake fault.

著者

飯田 汲事

出版者

公益社団法人 日本地震学会

雑誌

地震 第1輯 (ISSN:00371114)

巻号頁・発行日

vol.13, no.3, pp.67-74, 1941-03-25 (Released:2010-11-17)

参考文献数

13

著者

正木 和明 坪井 利弘 飯田 汲事

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.1, pp.135-144, 1981-03-25 (Released:2010-03-11)

参考文献数

10

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Shear wave velocity, soil density and standard penetration test value in depth at 35 boring points in Nagoya area were measured by means of P and S wave-velocity logging up to about 100m in depth. The empirical equations for estimating shear wave velocity and soil density were derived on the basis of these underground data as well as soil characteristics. By making use of these equations and boring data (depth, standard penetration test value, soil age and soil facies), shear wave velocity and soil density in depth were estimated. By means of multi-reflection method of shear wave, transfer functions at about 280 mesh points in Nagoya area were calculated, and distributions of maximum amplification factors and predominant periods were obtained. It was found that maximum amplification factors were large and predominant periods were long in the western part of Nagoya area. The relation between the maximum amplification factor, and the damage ratio in the Nobi and the Tonankai Earthquakes was studied, and it was clarified that the larger maximum amplification factor the greater damage ratio bacame.

著者

永井 理子 菊地 正幸 山中 佳子

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.54, no.2, pp.267-280, 2001-09-20 (Released:2010-03-11)

参考文献数

25

被引用文献数

29 54

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In an attempt to examine the characteristic behavior of fault asperities (large slip areas), we comparatively studied two large earthquakes: the Tokachi-oki earthquake (M 7.9) of May 16, 1968 and the Sanriku-oki earthquake (M 7.5) of December 28, 1994, which have a partially common source area. Both the strong motion records at a regional network and the teleseismic body waves at global networks were analyzed to determine the detailed spatio-temporal distribution of moment release. The aftershock distribution, which may provide us with a more reliable location of asperity, was also re-examined using the same underground structure and the same algorithm for both events.The total seismic moment, Mo, and the source duration, T are obtained as: Mo=3.5×1021Nm; T=90s for the 1968 event, and Mo=4.4×1020Nm; T=60s for the 1994 event. It is also shown that the 1968 event consists of more than two asperities, one of which took a role of asperity again for the 1994 event. The distribution of relocated aftershocks, which fringe the major asperities, strongly supports this fact. A simple calculation indicates that the seismic coupling is almost perfect (100%) in this common asperity. We thus propose that there exist characteristic sites for asperities where fault slip occurs only as a seismic event, and that the individual asperities usually manifest M 7 class earthquakes but sometimes synchronize to cause M 8 class earthquakes.

著者

遠山 忠昭 檀原 毅 里村 幹夫

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.37, no.4, pp.539-547, 1984-12-25 (Released:2010-03-11)

参考文献数

4

被引用文献数

1 1

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Although γ-ray surveys have often been carried out in order to research active faults, clear correspondence of γ-ray intensity to faults has not always been obtained. We examined over again the methods of γ-ray surveys and the following two points came up as important problems.(a) The hole to set the senser of γ-ray survey meter must be bored in the same radius and depth at each survey point.(b) Much attention must be payed to the difference of surface materials.In order to confirm the usefulness of the method in which the above two points are taken into consideration, the γ-ray surveys were carried out along a line across the Himenoyu fault. This fault was formed at the time of North-Izu earthquake in 1930, and its traces are yet clearly found. A clear peak of γ-ray intensity was obtained at the position on the fault.Next, this method was applied to the Ono fault whose precise position has not yet known, and we estimated the position of the fault by the results of γ-ray surveys.

著者

荒井 克彦 小嶋 啓介

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.52, no.1, pp.219-227, 1999

著者

神田 茂

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.21, no.2, pp.141-142, 1968-08-30 (Released:2010-03-11)

著者

宮本 貞夫

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.7, no.2, pp.136-137, 1954

著者

佐藤 裕

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.33, no.3, pp.395-397, 1980-09-25 (Released:2010-03-11)

参考文献数

3

著者

平松 良浩 小阪 大

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.65, no.3, pp.251-254, 2013-01-31 (Released:2013-07-19)

参考文献数

11

被引用文献数

1

著者

渡辺 晃

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.26, no.2, pp.107-117, 1973-10-30 (Released:2010-03-11)

参考文献数

5

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Frequency distribution of magnitude of the ultramicro-earthquakes was studied by using the data of the Matsushiro earthquake swarm observed in December 1966.As a result of analyses, the Gutenberg-Richter's formula concerning the frequency distribution of magnitude was found to hold well for the magnitude range down to about -0.9. The number of shocks then decreased very sharply with decreasing magnitude and no shocks of magnitude less than -1.3 were registered, though still within the limit of detection capability of the sensors. The seismograms of smaller events, if any, should be identified as earthquake motions, because the signal to noise ratio for a minimum shock was yet about 3, so that smaller events could not be masked by disturbances.A crude estimation showed that the linear dimension of the focal region for the minimum shock was of the order of a couple of meters. The size of focus for the shock of magnitude -0.85, where a peak in the frequency distribution occurred, amounted roughly to double the size for the minimum one.

著者

森重 学

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.71, pp.1-11, 2018-05-10 (Released:2018-06-26)

参考文献数

82

被引用文献数

1 1