A software program "concerto" for analysis of satellite laser ranging data has been developed at the National Institute of Information and Communications Technology. To fully utilize the high precision of the range data, this analysis software is equipped with physical models that match or excel the precision of range data. This software has been applied to the following sub-centimeter subjects. First, our LAGEOS orbit agreed to that of other institute, at the level of 5 mm RMS in the radial component and 4 cm RMS in three dimensions. Second, its terrestrial reference frame contributes to define the scale and origin of ITRF2000. Third, it detects the satellite signature effects in AJISAI and GLONASS ranging data. Lastly, it also detects the atmospheric pressure loading displacement of laser ranging stations.

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Gravity data in Southwest Japan have been accumulated and carefully compiled by the Gravity Research Group in Southwest Japan from which we constructed an extensive and accurate gravity database. This database is composed of generous contributions of more than forty institutes and organizations. Currently, this database involves more than 144, 000 net gravity data mostly in Southwest Japan. We published their coordinates, gravity, and related values in a computer-readable form. This database consists of gravity data by Nagoya University (NU) (54.3% of total) and those by organizations other than NU (45.7% of total).Most of this database had not yet been published in a tabulated list nor in a digital form. This database is accurate enough (1) to produce high-resolution gravity anomaly and gravity relief maps in Japan as well as close-up maps of Bouguer anomaly for a restricted region such as Hanshin-Awaji area or Tokai area in Central Japan, and (2) to make novel and innovative approach to visual imaging of Bouguer anomaly distribution in Japan. We believe that this database contributes immensely to the progress of researches for geodesy and other earth sciences.

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Accuracy of terrain correction strongly depends on the grid spacing of digital elevation dataset used for calculation. In and around the Japanese Islands, both 50 m mesh elevation on land area and 500 m mean bathymetric data on sea area are available. In order to simplify calculation algorithm, we firstly generated a synthesized digital elevation and bathymetry dataset whose grid spacing is approximately 50 meters by combining several available digital topographic data. We named this dataset the "Synthesized Land and Sea 50 M Mesh Topographic Data in and around the Japanese Islands-Version 2004; LS50MJ04", which has a size of about 14 GB for 2-dimensional array with 7 byte/grid. We coded a terrain correction programsimulating topography as an assembly of a rectangular parallelepiped prism and neglecting the curvature of the earth's surface. Integration of gravitational effects due to each prism on a station is truncated at 50 km. The accuracy of calculation is evaluated to be of the order of 1 mGal or less. We can calculate terrain corrections due to both land and seafloor topogra phies within one procedure. The calculated terrain correction values are more sensitive to short wavelength topographic undulations compared with our former ones, and are consistent with other works. We applied this program for nearly 600 thousands gravity measurements in and around the Japanese Islands.

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The crustal movement associated with earth quake swarm activity of Hakone volcano from June 12 to the end of November, 2001 was detected by EDM network installed by the Hot Springs Research Institute of Kanagawa Prefecture. Although significant change was not recognized so much from the raw trend, subtraction of aver aged seasonal change from observed EDM trend allowed detecting of inflation for about 2.5 months at the beginning of the earthquake swarm. This trend was consistent with observations of GPS, tilt meter and distortion meter. Our EDM analysis also detected contraction tendency of the volcano about 2.5 months after the beginning of the earthquake swarm. The reason of this trend is still equivocal but could be caused by regional and shallow deformation.

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