Journal of the Geodetic Society of Japan
Online ISSN : 2185-517X
Print ISSN : 0038-0830
ISSN-L : 0038-0830
Search
Advanced search
OR
Browse
Search
Volume 54, Issue 2
Displaying 1-4 of 4 articles from this issue
Show all abstracts
    • |<
    • <
    • 1
    • >
    • >|
  • Observation of Hydrological Effects on Gravity by Using a Scintrex CG-3M Gravimeter
    A Case of Typhoon 200709 (FITOW) at Asama Volcano Observatory
    Kazunari Nawa, Mitsuhiko Sugihara, Yasuaki Murata, Takahito Kazawa, Ki ...
    2008 Volume 54 Issue 2 Pages 59-67
    Published: 2008
    Released on J-STAGE: February 25, 2013
    DOIhttps://doi.org/10.11366/sokuchi1954.54.59
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    We carried out continuous gravity observation with a Scintrex CG-3M gravimeter at Asama Volcano Observatory from September 4 to October 22 in 2007.We tried to detect hydrological gravity effects after heavy rainfall by Typhoon 200709 (FITOW). To detect hydrological gravity effects we supposed a simple tank model as proposed for the Matsushiro superconducting gravimeter observation, which model represented immediate gravity increase and gradual decrease after rainfall. Parameters of the tank model were estimated using an ABIC minimization iversion method and precipitation data as inputs. As a result, hydrological gravity effects were extracted from gravity residuals although gravity residuals included a large non-linear drift. And the extracted hydrological gravity effects corresponded to temporal gravity changes simultaneously observed with an FG5 absolute gravimeter. Our success promises expanding opportunities of continuous observation by using CG-3M gravimeters in the future.
    View full abstract
    Download PDF (2425K)
  • Daily Quality Control System of Satellite Laser Ranging Data for the ILRS Network
    Toshimichi Otsubo, Mihoko Kobayashi, Tadahiro Gotoh, Toshihiro Kubo-ok ...
    2008 Volume 54 Issue 2 Pages 69-79
    Published: 2008
    Released on J-STAGE: February 25, 2013
    DOIhttps://doi.org/10.11366/sokuchi1954.54.69
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    A quality control system for the global network of the International Laser Ranging Service (ILRS) has been developed utilizing the precise orbit determination technique. Laser-range obser- vation data for as many as 15 satellites are being processed every day within 24 to 48 hours after ranging observations, and the quality control numerical tables are available via web, ftp and email. The analysis reports, formerly provided by National Institute of Information and Communications Technology and currently by Hitotsubashi University, are widely used for detecting and alerting various kinds of problems.
    View full abstract
    Download PDF (4848K)
  • Evaluation of Detection Level of Crustal Deformation Observation in the Time Domain through Power Spectrum Analysis
    Takeyasu Yamamoto, Akio Kobayashi, Akio Katsumata, Shigeo Mori
    2008 Volume 54 Issue 2 Pages 81-91
    Published: 2008
    Released on J-STAGE: February 25, 2013
    DOIhttps://doi.org/10.11366/sokuchi1954.54.81
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    We evaluated detection levels in the time domain through the power spectra from timeseries data in order to investigate the detection abilities of the volumetric strainmeter, the multicomponent strainmeter and the GPS in the Tokai and Kanto regions for crustal deformation over a wide range of time constants. The power spectra of the strainmeter data was approximately inversely proportional to the square of the frequency f in all of the frequency domains, whereas the power spectra of the GPS data had white noise in a cycle shorter than approximately 100 days and approached f-2 in the longer cycle. These results agree with those reported in previous studies. Detection levels evaluated from the power spectra were consistent with previously estimated noise levels at certain time intervals. The evaluated detection levels of the strainmeters were widely distributed at every observation point and appeared to be dependent on both the installed depth and the media around the strainmeter. The detection level decreased as the time interval T became longer. The detection level of the strainmeter was proportional to T-0.5 in the strain rate, and the detection level of the GPS was proportional to T-1. The linear strain, areal strain and displacement caused by the long-term SSE and the short-term SSE in the Tokai region were compared with the evaluated detection levels to examine the possibility of SSE detection. These were found to be appropriate indices of detection level, because the evaluated detection levels adequately represented the actual detection of the deformations. Furthermore, the comparison suggested that the GPS may not observe both types of SSE and that the strainmeter has potential for observing long-term SSE.
    View full abstract
    Download PDF (3341K)
  • Reports on the GGOS Workshop, November 2007, Italy, and the IAG Executive Committee Meeting, April 2008, Austria
    Kosuke Heki
    2008 Volume 54 Issue 2 Pages 93-94
    Published: 2008
    Released on J-STAGE: February 25, 2013
    DOIhttps://doi.org/10.11366/sokuchi1954.54.93
    JOURNAL FREE ACCESS
    Download PDF (198K)
    • |<
    • <
    • 1
    • >
    • >|
feedback
 Top