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Hokkaido University Collection of Scholarly and Academic Papers (130.615 recursos)

HUSCAP (Hokkaido University Collection of Scholarly and Academic Papers) contains peer-reviewed journal articles, proceedings, educational resources and any kind of scholarly works of Hokkaido University.

?????????????? = Geophysical bulletin of Hokkaido University

Mostrando recursos 1 - 20 de 768

  1. 2014年7月8日に発生した北海道白老町付近(胆振地方中東部)の地震(MJMA5.6)について(電子付録)

    一柳, 昌義; シェスタコフ, ニコライ; 奥山, 哲; 大園, 真子; 笠原, 稔; 高橋, 浩晃

  2. 十勝岳火口周辺域での重力鉛直勾配測定

    高橋, 浩晃; 大園, 真子; 一柳, 昌義; 山口, 照寛; 岡田, 和見; 齊藤, 一真; 不破, 智志; 伊藤, ちひろ; 岡崎, 紀俊; 高木, 朗充; 本多, 亮

  3. GNSS観測に基づく2016年熊本地震(M7.3)の余効変動時系列解析による九州地方の粘性構造の推定

    不破, 智志; 大園, 真子
    In order to investigate the viscosity distribution beneath the Kyushu Island, we analyzed postseismic time series of Global Navigation Satellite System induced by the 2016 Kumamoto earthquake(M7.3) . For the ~1.5 years of daily coordinates at 135 GEONET stations, we fitted theoretical time evolutions with two approaches.(1) Assuming that the first 50-days is dominated by the afterslip, we applied both of logarithmic and exponential functions. For the estimation, we firstly found the appropriate common time decay constants for the afterslip(0.996 days) , then estimated other parameters.(2) Ignoring first rapid afterslip signals, we fitted only exponential function for the time series...

  4. 3次元速度構造を考慮した襟裳岬周辺における地震の震源決定

    椎名, 高裕; 高橋, 浩晃; 勝俣, 啓; 一柳, 昌義
     In order to evaluate differences in an earthquake distribution in one- or three-dimensional velocity structures, we tried re-determinations of locations of earthquakes occurred around the Erimo cape, Hokkaido, Japan, in the three-dimensional heterogeneous model. Because of lowvelocity anomaly developed beneath the Hidaka mountain range, the relocated earthquakes mark that their focal depths tend to decrease. The maximum focal depth change is about 15 km. These changes of relocated earthquakes from those estimated in the one-dimensional model suggest that precise determinations of hypocenter considering realistic, three-dimensional velocity structure would improve our understandings for seismic activity and their focal mechanism around the...

  5. 十勝岳重力観測網での2機種の相対重力計による測定値の比較

    岡田, 和見; 高橋, 浩晃; 一柳, 昌義; 岡崎, 紀俊; 高木, 朗充
    Simultaneous relative gravity measurements using three SCINTREX CG5 and one LaCoste & Romberg G gravimeters were carried out in active Tokachi-dake volcano. No tares were identified in all measurement series. Differences in measured relative gravity values between the CG5#0033 and G#791 were less than 0.023 mGal for each observation point. Maximum difference between CG5#0552 and G#791, however, reached to 0 .196 mGal. Discrepancy between CG5#0552 and CG5#0033 was also recognized. Above differences seemed to correlate with relative gravity and altitude from reference to stations. These results suggested possible larger difference between individuals but lesser between gravimeter models. Investigation of possible...

  6. 2014年7月8日に発生した北海道白老町付近(胆振地方中東部)の地震(MJMA 5.6)について

    一柳, 昌義; シェスタコフ, ニコライ; 奥山, 哲; 大園, 真子; 笠原, 稔; 高橋, 浩晃
    A M5.6 shallow earthquake occurred on 8 July 2014 in middle east Iburi region, southwestern Hokkaido. Maximum seismic intensity of 5- was observed at Shiraoi town. Three temporal seismic stations had been installed in the focal region from 9 July 2014 to 30 April 2015. We determined 384 aftershock hypocenters by the double-difference tomographic hypocenter determination with proper seismic velocity structure. Relocated aftershocks were clearly distributed on a southeastern ward dipping plane with 5~10 km depth. This configuration agreed with a nodal plane of mainshock focal mechanism. Aftershocks occurred in surrounding part of a low seismicity patch. Mainshock was located...

  7. 道東カルデラ火山地域における絶対重力測定

    名和, 一成; 宮川, 歩夢; 山崎, 雅; 望月, 一磨; 高橋, 浩晃; 大園, 真子; 岡田, 和見; 岡, 大輔; 岡崎, 紀俊; 本多, 亮
     For the purpose of the establishment of the gravity base station, we carried out absolute gravity measurements in the vicinity of Akan and Kussharo caldera area, eastern Hokkaido, Japan. The measurements were conducted in a period between September 7 and 8 at Akan gravity station and between September 9 and 11 at Teshikaga gravity station, by using a FG5 #217. The gravity values determined for the Akan station and the Teshikaga station at the floor level are 980444641 μGal, 980518903 μGal, respectively.

  8. CG-5重力計の登山を伴う野外調査時における重力値安定性の基礎調査

    高木, 朗充; 宮城, 洋介; 小澤, 拓; 本多, 亮; 高橋, 浩晃
    The shake by mountain climibing influences the graviity measurement with CG-5 graviemeter. To investigate this influence, we conducted two investigations: the dynamic and the static disturbances. The dynamic disturbance means swing caused by walking, and the static disturbance means a tilt of the gravimeter with long time in carrying. In the investigation of the dynamic disturbance, measured gravity leaped negatively just after the climbing, but they did not correlate to times of climbing. In the investigation of the static disturbance, we found the correlation between leap values of gravity and duration times of tilt in the case of tilt angle...

  9. 目次(英語)・奥付・裏表紙

  10. 表紙・編集委員・目次(日本語)

  11. 目次(英語)・奥付・裏表紙

  12. 2003年十勝沖地震(M8.0)による北海道地域の地震時歪み異常分布の検出

    石森, 健太朗; 大園, 真子
    Observed coseismic crustal deformation is an answer of the elastic response induced by the seismic fault dislocation. Because real subsurface structure is not pure elastic space, thus the observed coseismic displacement distribution probably different from the predicted displacement field when we assume the pure elastic medium. By the coseismic strain analysis using dense GNSS network at the 2011 Tohoku-oki earthquake, a supporting result, which shows that the strain anomaly related to inhomogeneous subsurface structure, is proposed. However, there is no other previous study. Therefore, we try to detect the same relationship from coseismic displacement at the 2003 Tokachi-oki earthquake. After...

  13. 2016年6月16日に発生した函館市南茅部付近の地震(MJMA 5.3)と余震活動

    一柳, 昌義; 高田, 真秀; 高橋, 浩晃
    A M5.3 shallow earthquake occurred on 16 June 2016 in Minamikayabe region, southern Hokkaido. Three temporal seismic stations had been operated in the focal region from 18 June 2016 to 29 August 2016. Initial hypocenters and 1-D P-wave velocity structure were estimated from waveform data of temporal and permanent seismic stations. Fine aftershock distribution inferred from the double-difference procedure showed that the hypocenters were distributed in NW-SE direction, which might be agree with a fault plane of mainshock focal mechanism. Five foreshocks occurred near mainshock hypocenter showed similar waveform with high correlation. Characteristic persistent background seismicity and latest middle size...

  14. 表紙・編集委員・目次(日本語)

  15. 雌阿寒岳ナカマチネシリ火口の全磁力変化と熱活動

    田中, 良; 橋本, 武志; 鈴木, 敦生
    We performed measurements of the magnetic total intensity at Nakamachineshiri crater of Meakandake volcano, eastern Hokkaido, in 2013, 2014 and 2015. Comparing the three campaigns, we found small but systematic magnetic changes suggesting demagnetization at the shallow subsurface of the crater during 2014-2015. We estimated the best-fit demagnetized source as a sphere with magnetic moment of 2×106 Am2 at a depth of 250 m (960 m a.s.l) beneath the crater. We then considered it was brought by thermal demagnetization, and made an order estimation of the heating rate at the source by assuming a simplistic temperature-magnetization relationship. In addition, we...

  16. 十勝岳白銀荘での重力鉛直勾配測定

    高橋, 浩晃; 一柳, 昌義; 岡崎, 紀俊; 高木, 朗充; 宮城, 洋介; 本多, 亮
    Measurements for vertical gradient of gravity were carried out on mountain slope of active Tokachidake volcano. Round-trip gravity measurements at a lower and an upper surfaces of a tripod with about 0.97 m height difference using four SCINTREX CG5 gravimeters were conducted. Estimated gravity gradient were 0.285 to 0.290 mGal/m. These values were smaller than the Free-air gradient of 0 .3086 mGal/m, which is usually referred. Effect from local terrain was suggested because of precipitous topography. Estimations of gravity gradient near active crater by direct measurements and numerical simulation are desirable to evaluate ground deformation effects in gravity change due...

  17. 目次(英語)・奥付・裏表紙

  18. 表紙・編集委員・目次(日本語)

  19. 2015年に発生した阿寒湖付近の地震(MJMA 5.0)

    一柳, 昌義; 高橋, 浩晃; 山口, 照寛; 岡田, 和見; 大園, 真子; 岡崎, 紀俊
    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.

  20. 目次(英語)・奥付・裏表紙

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