著者

川口 則幸

出版者

日本測地学会

雑誌

測地学会誌

巻号頁・発行日

vol.35, no.2, pp.105-115, 1989

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1984年から実施している鹿島一筑波間VLBI実験において,観測誤差を越える系統的変動がみられた.この変動が統計的に有為であるかどうかを,誤差解析を行うことで評価した.この結果,観測誤差の見積が正しいこと,系統的変動がこの観測誤差の3倍にも達すること,などが確認された.この変動が,千葉東方沖地震によって発生したものであるかどうか調べるために,この地震の震源パラメータから地表面の変動を計算してみた.計算の結果,変位の方向が逆極性であること,変位の絶対量が観測値の5分の1に過ぎないことなどが明らかになり,単純な断層モデルでは説明がつかないことが分かった.

著者

萩原 幸男

出版者

日本測地学会

雑誌

測地学会誌 (ISSN:00380830)

巻号頁・発行日

vol.30, no.2, pp.92-106, 1984-08-25 (Released:2010-09-07)

参考文献数

6

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Suppose an arbitrary function expressed in a surface spherical harmonic expansion series when the pole is translocated at an arbitrary point on the surface of a sphere. The coefficients of the expansion series are functions of the latitude and longitude of the translocated pole. GANEKO [6] has derived the general transformation formula of spherical harmonic expansion coefficients in a form of the modified Jacobi polynomials. It can be applied to theoretical problems of geodesy and geophysics including the translocation of the polar axis. This paper shows a simple method for deriving GANEKO's transformation formula and its inverse one, with their applications to the global geoidal height.

著者

平岡 喜文 横川 正憲 根本 盛行 村山 盛行 武山 峰典

出版者

日本測地学会

雑誌

測地学会誌 (ISSN:00380830)

巻号頁・発行日

vol.57, no.4, pp.173-180, 2010 (Released:2012-03-30)

参考文献数

5

---

We developed a new Remote GPS Monitoring System (REGMOS) -Hybrid which utilized the Broadband Global Area Network (BGAN) of Inmarsat PLC and solar cell modules for data transfer and power supply, respectively. It can equip many kinds of sensors including GPS, camera, thermometer, tiltmeter and so on to monitor volcanoes and crustal activities. The original REGMOS was first developed in 1998. The purpose of the development is to monitor crustal deformation in a severe environment where infrastructures including electric power and wired telephone line is not available, for example, a volcanic field and an area damaged by an earthquake. In the original system, the data transfer using satellite telephone services is unstable and slow (4.8 kbps) and GPS is an only sensor for crustal monitoring. It was pointed out that various kinds of data such a photo of a crater were important to monitor volcanic activities. Therefore, we developed the new REGMOS-Hybrid to overcome the problems of the data communication and power generation in the original system. We installed the REGMOS-Hybrid on the summit of Mt. Tarumae volcano in Hokkaido in August 2010. It has enabled us to monitor the volcanic activity for more than one year without any troubles of the whole system. The other kinds of data including a movie and geomagnetism have been already supported by the REGMOS-Hybrid. We plan to acquire these data in a practical field.

著者

岩田 隆浩 南野 浩之 佐々木 健 小川 美奈 並木 則行 花田 英夫 野田 寛大 松本 晃治 今村 剛 石原 吉明 鶴田 誠逸 浅利 一善 劉 慶会 菊池 冬彦 Goossens Sander 石川 利昭 河野 宣之 高野 忠

出版者

日本測地学会

雑誌

測地学会誌 (ISSN:00380830)

巻号頁・発行日

vol.55, no.2, pp.135-150, 2009 (Released:2012-03-28)

参考文献数

16

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SELENE Main Orbiter (KAGUYA) has separated two small sub-satellites; (1) the Relay Satellite “OKINA (Rstar)”, and (2) the VLBI Radio Satellite “OUNA (Vstar)”. These sub-satellites started to perform 4-way Doppler measurements using Relay Satellite Transponder (RSAT) and multi-frequency phase-delay differential VLBI using VLBI Radio Sources (VRAD) for lunar gravity mapping. We have developed the frequency conversion system, multi frequency S/X-band vertical dipole antenna, and light weighted S-band patch antenna to perform these missions. Simple structured release mechanism has also been developed and confirmed its performance by ground test and orbital demonstration using micro-Lab Sat. Initial check out were executed and properties of satellite bus equipments, onboard mission instruments, and observation systems including ground stations were evaluated. Electric power and thermal control subsystems have shown that they conduct as designed and inspected in the ground tests. The release mechanisms have given the spin which can maintain the stability of the satellite attitudes. Communication functions of mission instruments conform to the link budgets. These results suggest that OKINA and OUNA have enough performances to produce efficient data by RSAT/VRAD gravity observations.

著者

上谷 良吉

出版者

日本測地学会

雑誌

測地学会誌 (ISSN:00380830)

巻号頁・発行日

vol.6, no.3, 1960-12

著者

藤原 了 橋本 学 竹本 修三

出版者

日本測地学会

雑誌

測地学会誌 (ISSN:00380830)

巻号頁・発行日

vol.47, no.2, pp.659-678, 2001-06-25 (Released:2011-03-01)

参考文献数

44

被引用文献数

1

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三次元有限要素法を用いて琉球弧をモデル化し,粘性流体媒質中の定常流の仮定下で流れ及び応力場を計算した.背弧直下に想定される低密度媒質及び一般的なプレート運動の原動力の背弧拡大に対する効果,地殻粘性率の影響について考察した.解析の結果,スラブ引っ張り力やリッジプッシュ等のみを考慮したモデルでは背弧地域に圧縮場を形成した.一方,背弧直下での低密度媒質に働く浮力を考慮した場合,背弧における拡大を示唆する張力場が得られた.背弧直下の低密度媒質は地殻付近の深さまで到達している可能性が高く背弧拡大の主原動力と考えられる.さらにマントルの粘性率と背弧領域の地殻粘性率との差が小さい時,すなわち相対的に軟らかいプレートを仮定した時に拡大が生じた.

著者

瀬戸 孝夫 田中 穣 田島 稔

出版者

日本測地学会

雑誌

測地学会誌 (ISSN:00380830)

巻号頁・発行日

vol.16, no.1-2, pp.34-39, 1970-08-25 (Released:2011-07-05)

参考文献数

14

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Observations of magnetic variations were made by means of portable fluxgate type magnetometers at Akagane (cp = 39°10:6 N, λ =141°20:6 E), Ishibuchi (ψ = 39°06:7 N, A = 140°54:6 E), Yuzawa (ψ = 39°10:2 N, A = 140°29:8 E) and the Mizusawa Geodetic Observa-tory (ψ = 39°06:5 N, A = 141°12:4 E) for the purpose of studying the conductivity anomaly along the east-west line including the Observatory in the Tohoku district of Japan. Using the observed events having the duration time longer than 30 minutes, the ele-ments of Parkinson Vector at four stations are obtained as shown in Table, whose direc-tions are eastward and opposite from those obtained by using the data of geomagnetic micropulsations having the periods of 10-60 seconds. A brief discussion was made about the relation between the conductivity anomaly and the crust and upper mantle structure in the Tohoku district which has typical geo-physical characteristics among circum-pacific island arcs.

著者

溝上 恵

出版者

日本測地学会

雑誌

測地学会誌 (ISSN:00380830)

巻号頁・発行日

vol.8, no.1, pp.29-37, 1962-12-30 (Released:2010-09-07)

参考文献数

5

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It is the well known fact that notable relations exist between the distribution of Bouguer gravity anomalies and the structural units of the surface geology in Hokkaido, which have been formed by the orogenic movements since the Miocene period. For example, the Hidaka mountains which have been violently upheaved in the most recent geologic age, are areas of remarkably high gravity while the Tempoku-Urakawa Zone which have rapidly subsided in the same age is the area of strong negative anomalies running parallel to the mountains. In this paper, it is shown that the pattern of the strong negative anomalies of the Tempoku-Urakawa Zone can be explained by Vening Meinesz's theory of visco-elastic deformation of the crust by compressive stress. Time required for the deformation of the crust and density of sedimentary layer was also calculated and these results are in good harmony with the geohistorical evidence in this region.

出版者

日本測地学会

雑誌

測地学会誌 (ISSN:00380830)

巻号頁・発行日

vol.19, no.4, pp.244-244, 1974-03-25 (Released:2011-03-01)

出版者

日本測地学会

巻号頁・発行日

1954

著者

小林 裕太 日置 幸介

出版者

日本測地学会

雑誌

測地学会誌 (ISSN:00380830)

巻号頁・発行日

vol.58, no.2, pp.89-93, 2012-10-25

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The Earth's spin axis moves by various factors, and mass redistribution associated with seismic faulting is also expected to contribute to this movement. However, there have been no space geodetic observations of coseismic polar motion excitations to date. In this study, we analyze the time series of the excitation functions of the polar motion, and try to detect steps due to the three recent M9 class earthquakes, i.e. the 2004 Sumatra-Andaman, the 2010 Chile (Maule), and the 2011 Tohoku-Oki earthquakes. For the 2010 Chile earthquake, a significant step was detected but was not consistent with the anticipated direction.

著者

小菅 正裕 池田 仁美 鎌塚 吉忠 佐藤 裕

出版者

日本測地学会

雑誌

測地学会誌 (ISSN:00380830)

巻号頁・発行日

vol.32, no.4, pp.290-302, 1987-03-25 (Released:2011-07-05)

参考文献数

17

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A fault model of the 1983 Nihonkai-chubu (Japan Sea) earthquake (MJMA 7.7) was investigated on the basis of aftershock distributions, crustal deformation, and tsunami data. Since the earthquake took place under the sea off the coast of northwestern Tohoku District, there are a few land observation of crustal movement near the source area. We, therefore, have estimated the static fault parameters by comparing the wave form of observed tsunami with that of calculated from the static fault model. Trial fault parameters were derived from seismic data: focal mechanism solutions, seismic moment, and aftershock distributions with reference to the rupture process of the main shock. Our model was characterized by three fault planes trending NNE-SSW in the southern and the middle parts and NNW-SSE in the northern part, and by their low dipangle of 25°. The tsunami wave form was simulated numerically by a finite difference method. The fault model derived from seismic data reasonably explains the geodetic data and tsunamis. The calculated vertical deformation of land was consistent with the observed subsidence of 30-40 cm at Kyuroku island situated near the source area, and those of a few centimeters at Oga peninsula and Fukaura. The tsunami wave form observed at tide-gage stations along the coast of the Japan Sea was well simulated by our model as well as the model with higher dip angle. The data of strain step observed by extensometers installed in northern Japan support the low angle thrust event.

著者

小林 佑輝 岩野 祥子 福田 洋一

出版者

日本測地学会

雑誌

測地学会誌 (ISSN:00380830)

巻号頁・発行日

vol.50, no.1, pp.17-26, 2004-03-25

著者

岩野 祥子 福田 洋一

出版者

日本測地学会

雑誌

測地学会誌 (ISSN:00380830)

巻号頁・発行日

vol.46, no.2, pp.149-152, 2000-06-25

被引用文献数

3

著者

小林 裕太 日置 幸介

出版者

日本測地学会

雑誌

測地学会誌 (ISSN:00380830)

巻号頁・発行日

vol.58, no.2, pp.89-93, 2012 (Released:2013-02-26)

参考文献数

16

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The Earth’s spin axis moves by various factors, and mass redistribution associated with seismic faulting is also expected to contribute to this movement. However, there have been no space geodetic observations of coseismic polar motion excitations to date. In this study, we analyze the time series of the excitation functions of the polar motion, and try to detect steps due to the three recent M9 class earthquakes, i.e. the 2004 Sumatra-Andaman, the 2010 Chile (Maule), and the 2011 Tohoku-Oki earthquakes. For the 2010 Chile earthquake, a significant step was detected but was not consistent with the anticipated direction.

著者

小林 昭夫 吉田 明夫

出版者

日本測地学会

雑誌

測地学会誌 (ISSN:00380830)

巻号頁・発行日

vol.50, no.1, pp.39-42, 2004-03-25 (Released:2010-09-07)

参考文献数

11

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We investigated crustal deformation after the 1946 Nankai earthquake using tide gauge records. Although resolution of tide gauge records is not so high for seeing the temporal change in detail, vertical crustal movements whose relaxation times are between several months to years can be detected by them. It was reported that there had been a postseismic crustal deformation with a time constant of 4-5 months in southern Kui Peninsula (Kobayashi et al., 2002). In this paper we show that crustal deformations with a longer relaxation time of a few years were observed in northern Shikoku, examining tide gauge records at such stations as Takamatsu, Sumoto and Kobe. These observations suggest that there was a time lag in the development of postseismic slip between shallow and deeper parts on the plate interface after the Nankai earthquake.

著者

小林 昭夫 真砂 礼宏 吉田 明夫

出版者

日本測地学会

雑誌

測地学会誌 (ISSN:00380830)

巻号頁・発行日

vol.48, no.1, pp.1-12, 2002-03-25 (Released:2011-03-01)

参考文献数

28

被引用文献数

1

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We examined tide gauge records at stations in and around the Kui peninsula to find if a precursory crustal deformation occurred before the 1946 Nankai earthquake. First, we removed effects of atmospheric pressure and astronomical tide on the records. Then, we tried to get rid of the effects of the oceanic current by taking the difference of the records betweentwo stations. After these corrections we found that sea level at Uragami where is located on the southeastern coast of the Kui peninsula had risen about 10 cm just before the Nankai earthquake. The sea level change, if we consider that to represent real subsidence of land near Uragami, could be explained by supposing that a slow fault slip corresponding to moment magnitude 6.9 occurred on the plate boundary in the offing of southeast of the Kui peninsula near the hypocenter of the Nankai earthquake.

出版者

日本測地学会

雑誌

測地学会誌 (ISSN:00380830)

巻号頁・発行日

vol.22, no.2, pp.65-76, 1976-09-25 (Released:2010-09-07)

参考文献数

11

---

A new gravimetric network, named the Japan Gravity Standardization Net 1975 (JGSN 75), was established and new gravity values were determined on the basis of the International Gravity Standardization Net 1971 (IGSN 71). A reliable gravimetric net has been organized in Japan by combining results of the GSI pendulum and gravimeter measurements by the Geographical Survey Institute and gravity values were determined in the Potsdam system referring to the value at the old pendulum station in Tokyo. The IGSN 71 published in 1974 contains 16 common stations with the national net. If the old reference value in Tokyo has no error, a discrepancy in gravity values at every common station must be equal to -14.0 milligals; a correction to the Potsdam absolute value. The present comparison showed that the discrepancy took mostly a constant value within a range of ±0.06 milligals. The mean value and the standard deviation were -13.80±0.03 milligals for the most districts and -14.00±0.03 milligals for the Kyushu District. No systematic inclination against the gravity value was found. This means that the scale of the Japanese gravimetric net agrees well with that of the IGSN 71. Therefore, the gravity value hitherto adopted in Japan can be converted into new one based on the IGSN 71 only by adding a constant value. New gravity values were obtained for 122 stations throughout the country and are given in this report. These are the results of repeated measurements including many new ones with LaCoste & Romberg gravimeters of which calibration constant values were corrected with our pendulum or the IGSN 71 results. A relative accuracy in this net is considered to be ±0.035 milligals and an absolute accuracy is the same as that ofthe IGSN 71. The JGSN 75 will serve as the framework of the gravimetric net in the country and should be used for all gravity works. The old Potsdam system values in Japan should be changed into new ones based on the JGSN 75.

著者

飛田 幹男 河瀬 和重 政春 尋志

出版者

日本測地学会

雑誌

測地学会誌 (ISSN:00380830)

巻号頁・発行日

vol.55, no.3, pp.315-324, 2009 (Released:2012-03-28)

参考文献数

10

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Three equations for meridional distance from the equator are compared. Accuracies, advantages and disadvantages are discussed. Conventional equation with higher terms has enough accuracy and slow convergence. Bessel’s simple equation is very easy for computer programming and has the fastest convergence and the fastest calculation speed. An analytic equation derived from elliptic integrals is easy for programming and has fast convergence and the highest accuracy.