文献一覧: 北海道大学地球物理学研究報告 (雑誌)

1 0 0 0 OA 北海道手稲鉱山産Te, Bi, As 鉱物

著者: 島倉広至三浦貴生浜根大輔松枝大治三浦裕行
出版者: 北海道大学大学院理学研究院
雑誌: 北海道大学地球物理学研究報告 (ISSN:04393503)
巻号頁・発行日: vol.78, pp.19-35, 2015-03-19

The Teine mine is a epithermal Au-Ag-Cu deposit located at the west part of Sapporo, Hokkaido, Japan. More than 30 veins are distributed in the 5km2 area. So far, 48 mineral species are reported from the Teine mine. However, mineralogical study is not enough to describe the wide variety of mineral occurrence in this mine. The authors perform a descriptive study of ore samples stored at the Hokkaido University Museum and found 15 newly observed minerals from the Teine mine. Especially, cupropavonite,hodrushite,koritnigite, krautite and poubaite are first report from Japan. Poubaite, PbBi2Se2Te2, found in goldfieldite grain, is idiomorphic and less than 30 μm in diameter. It shows creamy white color and metallic luster. Bireflectance is strong. The observed empirical formula, PbBi2(Te2.0Se1.9S0.1) Σ4, is consistent with the ideal formula (Zdenek et al., 1987).

2021-05-28 10:49:13
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1 0 0 0 OA 京都大学~比叡山頂間の高頻度キャンペーン重力データから推定された可搬型相対重力計の相対スケールファクター

著者: 若林環風間卓仁
出版者: 北海道大学大学院理学研究院
雑誌: 北海道大学地球物理学研究報告 (ISSN:04393503)
巻号頁・発行日: vol.84, pp.11-20, 2021-03-26

Campaign relative gravity measurement is one of the most powerful methods to monitor spatiotemporal mass variations associated with volcanic activities. In order to quantify volcanic gravity variations accurately, the systematic gravity error due to scale factor should be corrected from original gravity data. We therefore determined relative scale factors of portable relative gravimeters, using relative gravity values measured at six gravity points between Kyoto University and Mt. Hiei in 2020 frequently. We here calculated the relative scale factor of each gravimeter by dividing the gravity value of the LC-G534 gravimeter by that of the corresponding gravimeter. The scale factor of the LC-G680 gravimeter relative to the LC-G534 gravimeter was obtained to be 0.999900 ± 0.000067; although the gravity difference between Kyoto University and Mt. Hiei (about 167 mGal) was not so large for the scale factor calibration, we succeeded in determining the G680’s relative scale factor with small standard deviation because the measurement error of the gravity data became smaller thanks to the frequent gravity measurements. However, the relative scale factors for LC-G680 and D-58 as of 2020 were found to be different from those in 2018 by more than 0.0002. In addition, the standard deviations of the relative scale factors for LC-D58 and CG-5 were obtained to be greater than 0.0002. These results may be related to significant temporal variations in reading values, originating from the overhaul in 2019 (LC-G680), the manual adjustment of the reading range (LC-D58) and the large instrumental drift (CG-5). Our results also imply that scale factor values for LaCoste-type gravimeters can depend on their reading values, as mentioned in a previous study for Scintrex-type gravimeters.

2021-03-26 15:17:34
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1 0 0 0 IR 2010年12月2日に札幌市直下で発生した石狩地方中部の地震(MJMA4.6)と札幌周辺の地震活動

著者: 一柳昌義山口照寛高田真秀東龍介黒井和典山田卓司高橋浩晃前田宜浩
出版者: 北海道大学大学院理学研究院
雑誌: 北海道大学地球物理学研究報告 (ISSN:04393503)
巻号頁・発行日: no.76, pp.1-13, 2013-03

2021-03-15 03:00:08
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1 0 0 0 IR 飛行機雲の偏波ライダー観測

著者: 播磨屋敏生本間晃梶川正弘
出版者: 北海道大学大学院理学研究科地球惑星科学専攻(地球物理学)
雑誌: 北海道大学地球物理学研究報告 (ISSN:04393503)
巻号頁・発行日: no.66, pp.11-31, 2003-03

2021-02-10 09:30:18
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1 0 0 0 IR 2007年サハリン西方沖の地震(Mw6.2)の震源特性

著者: 前田宜浩笠原稔
出版者: 北海道大学大学院理学研究院自然史科学部門(地球物理学)
雑誌: 北海道大学地球物理学研究報告 (ISSN:04393503)
巻号頁・発行日: no.72, pp.219-230, 2009-03

2020-12-01 08:30:07
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1 0 0 0 IR 歴史的視点から見た地震学と社会 (強震動シンポジウム(札幌)記念号)

著者: 武村雅之
出版者: 北海道大学大学院理学研究院自然史科学部門(地球物理学)
雑誌: 北海道大学地球物理学研究報告 (ISSN:04393503)
巻号頁・発行日: no.73, pp.1-22, 2010-03

The Great Hanshin-Awaji Earthquake Disaster in 1995 killed more than 6000 people. At that moment, the Seismological Society of Japan and the Japanese government examined themselves and fully recognized that communications beneficial for disaster prevention were not sufficiently exchanged and valuable knowledge obtained from earthquake research were not efficiently applied to the general public and disaster prevention organizations. The Seismological Society of Japan established new committees in charge of publicity and education in 1996 to provide opportunities of the communication between seismologists and general public. The Japanese government also established the Headquarters for Earthquake Research Promotion as a direct system of accountability for government policies regarding earthquakes. Since 1880, the year of the establishment of the first Seismological Society in the world, the Japanese seismological community has experienced 4 big changes such as the Great Nobi Earthquake Disaster in 1891, the Great Kanto Earthquake Disaster in 1923, the Second World War, and this earthquake disaster. These histories are reviewed from the point of view of social activities in Japanese seismology. Finally, we will discuss achievement for the sake of the mitigation of earthquake disaster on the lessons learned from the history.

2020-11-28 20:54:13
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1 0 0 0 IR 2004年12月14日留萌支庁南部の地震(M6.1)

著者: 前田宜浩笹谷努一柳昌義山口照寛高橋浩晃笠原稔
出版者: 北海道大学大学院理学研究科地球惑星科学専攻(地球物理学)
雑誌: 北海道大学地球物理学研究報告 (ISSN:04393503)
巻号頁・発行日: no.68, pp.243-253, 2005-03
被引用文献数: 2

2020-07-16 15:34:01
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1 0 0 0 OA 2015年に発生した阿寒湖付近の地震(MJMA 5.0)

著者: 一柳昌義高橋浩晃山口照寛岡田和見大園真子岡崎紀俊
出版者: 北海道大学大学院理学研究院
雑誌: 北海道大学地球物理学研究報告 (ISSN:04393503)
巻号頁・発行日: vol.79, pp.1-8, 2016-03-19

An M5.0 shallow earthquake occurred on 4 June 2015 in the eastern Hokkaido. In order to evaluate aftershock activity, three temporal seismic stations had been operated in the focal region from 4 June 2015 to 22 August 2015. Hypocenters calculated with a local seismic velocity structure indicated clear southwestern-dipping distribution. This alignment on a plane was consistent with one of nodal plane of mainshock focal mechanism. This earthquake and historical records suggested higher seismic activity in this region.

2020-06-15 11:51:58
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1 0 0 0 OA 6.閉塞湖からの分水界漏出倶多楽湖

著者: 中尾欣四郎大槻栄田上龍一成瀬廉二
出版者: 北海道大学理学部地球物理学教室
雑誌: 北海道大学地球物理学研究報告 (ISSN:04393503)
巻号頁・発行日: vol.17, pp.47-64, 1967-02-20

2020-06-15 11:34:17
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1 0 0 0 日本列島における深部低周波地震の発生状況

著者: 高橋浩晃宮村淳一
出版者: 北海道大学大学院理学研究院自然史科学部門(地球物理学)
雑誌: 北海道大学地球物理学研究報告 (ISSN:04393503)
巻号頁・発行日: no.72, pp.177-190, 2009-03

2020-05-07 20:26:33
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1 0 0 0 OA 可搬型相対重力計を用いた重力連続観測 : システムの概要およびラコスト重力計G680による観測例

著者: 風間卓仁
出版者: 北海道大学大学院理学研究院
雑誌: 北海道大学地球物理学研究報告 (ISSN:04393503)
巻号頁・発行日: vol.83, pp.9-23, 2020-03-19

Relative gravity data is continuously collected using different types of portable relative gravimeters on a trial basis, toward the future utilization of continuous relative gravity measurements for monitoring spatiotemporal mass variations associated with volcanic activities. The gravity data is first recorded using the Tera Term software installed to a Windows-based PC; although a typical LaCoste & Romberg gravimeter does not have any devices to transmit its gravity value digitally, its analog voltage output from its readout socket can be converted to serial data format using an appropriate analog-digital converter. The recorded gravity data is then sent to an Ubuntu-based computer periodically to draw graphs of gravity time series. The graphs are finally uploaded to a web server so as to monitor temporal gravity variations anytime and anywhere. The above system for continuous relative gravity measurement was applied to the LaCoste G680 gravimeter, which was installed at the Kyoto-A gravity point, Kyoto University in September 2017. The G680’s gravity data in 2018 clearly showed time variations in short-period tide and annual instrumental drift. In particular, the instrumental drift was expressed by the linear gravity decrease of about 10 mGal/year and the additional annual gravity variation of about 1.5 mGal amplitude. These results suggest that typical LaCoste gravimeters can be utilized for continuous relative gravity measurements without major instrumental remodeling.

2020-03-27 16:34:14
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http://hdl.handle.net/2115/77089

1 0 0 0 OA 4.1968年1月29日色丹島沖地震の余震活動 : とくに本震直後の余震について

著者: 広田知保
出版者: 北海道大学理学部地球物理学教室
雑誌: 北海道大学地球物理学研究報告 (ISSN:04393503)
巻号頁・発行日: vol.21, pp.33-43, 1969-02-15

2020-03-17 09:04:52
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1 0 0 0 OA 巨大地震は火山の大噴火を励起するか?

著者: 小山順二
出版者: 北海道大学大学院理学研究院
雑誌: 北海道大学地球物理学研究報告 (ISSN:04393503)
巻号頁・発行日: vol.78, pp.53-68, 2015-03-19

After the 2011 Tohoku-oki megathrust earthquake of Mw 9.0, one of the great concern is whether or not the megathrust earthquake induces large volcanic eruptions and disastrous aftershocks in Japan. There exist 110 active volcanoes in Japan and large eruptions including historical events of each volcano have been compiled in terms of Volcanic Explosivity Index (VEI; Newhall and Self, 1982) from 0 (Non-explosive) to 8 (Mega-colossal). According to “Volcanoes of the World” by Siebert et al. (2010), we could find 50 eruptions in Japan since 600 A.D. classified as VEI 4 (Large) and 5 ~ (Very Large). Speaking about great earthquakes whose earthquake (moment) magnitude M (Mw) is equal to or larger than 8.0, there occurred 34 times since 684 A.D. in Japan. I have compared the time of occurrences of Large volcanic eruptions and large earthquakes (M>7.5) at first, taking examples of Mt. Fuji, Tokachidake, Hokkaido Komagatake and Sakurajima volcanoes. Since I could not find any systematic correlation between them, I decided to compare all the Large (and Very Large) volcanic eruptions and the great earthquakes (M>8.0) in Japan. In order to develop the quantitative discussion, we need to introduce cross-correlogram analysis (Perkel et al., 1967; Grun, 2009) for these two discrete point-processes. All that I could find was very poor correlation between great earthquakes and Large volcanic eruptions in Japan. It is true that many papers have been showing us the correlation between large earthquakes and volcanic eruptions. However, speaking about Large eruptions (not speaking about volcanic disasters), it is not true for the correlation between them. The reason is that some small-scale volcanic activity out of many volcanoes has been activated by great earthquakes almost all the time in the world. Even just after the 2011 Tohoku-oki megathrust, it has been reported that the volcanic activity of about 20 volcanoes in Japan has been enhanced. It is also true that some volcanoes are activated in the present, about 4 years after the megathrust. The evidences should be added, which are the eruptions of Mt. Fuji in 1707 (VEI 5), 49 days after the 1707 Hoei earthquake of M 8.6 and of Bezymianny in Kamchatka in 1956 (VEI 5), 4 years after the 1952 Kamchatka earthquake of Mw 9.2. Both of the volcanoes have spent about 900 ~ 1200 years of quiescence in the volcanic activity. All these would suggest that great earthquakes might induce Large volcanic eruptions nearby, however it is totally dependent on its own potential and preparedness to erupt of each volcano and the earthquakes just play a role of a trigger.