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Volume 43 (1997)
- Issue 4 Pages 213-
- Issue 3 Pages 133-
- Issue 2 Pages 33-
- Issue 1 Pages 1-
Volume 43, Issue 2
Displaying 1-6 of 6 articles from this issue
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Shaorong Zhao, Shuzo Takemoto1997 Volume 43 Issue 2 Pages 33-43
Published: July 25, 1997
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSFault plane parameters of the 1995 Hyogo-ken Nanbu earthquake (M=7.2) are esti mated from an inversion of GPS data, which reveals that the earthquake fault is charac terized by right-lateral strike slip (1.3±0.2 m) with a length of 32.8±1.0 km, a width of 14.7±1.0 km, a dip angle of 84.3°+1, 0°, a depth of 14.7±0.5 km, and a strike direction of 48.8°±1.0°. These results are roughly consistent with deductions made from seismic wave data and show good agreement with the distribution of aftershocks projected on the ground surface and in depth. Based on this fault model, we calculated the stress changes around the source region and found a significant stress concentration on the northeastern part of the rupture plane, which is responsible for the severe disruption that took place within the Belt of Damage and might have induced ruptures of sub-faults beneath the Kobe area.View full abstractDownload PDF (1133K) -
Yukio Takahashi, Yasuhiro Koyama, Tetsuro Kondo, Noriyuki Kurihara, Ta ...1997 Volume 43 Issue 2 Pages 45-65
Published: July 25, 1997
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSThe Geographical Survey Institute (GSI) and the Communications Research Labora tory (CRL) have conducted many domestic VLBI experiments since 1934. Here, we un dertake the baseline analyses of 54 domestic VLBI experiments using the same models and parameters. We present the results on the positions of 15 stations These positions make the reference of positions in Japan. The movements of six stations, Tsukuba, Koganei, Kanozan, Titijima, Shintomi, Minami-Daito are also obtained in the international coordinate system ITRF93. The differences between the observed movements and the NUVELI-A plate model are obtained to subtract the movements of each station predicted by the NUVELI-A plate model in the ITRF93 velocity field. These stations are located near plate boundary. The directions of differences agreed with the direction of the neighboring plate motion. Furthermore, the positions are obtained in the analyses with ionospheric delay corrections by S & X dual bands data, and without ionospheric delay corrections. Comparing these results, the effect of ionospheric delay correction on the station positions in the domestic VLBI experiments is investigated.View full abstractDownload PDF (1893K) -
Hideo Hanada, Yoshiaki Tamura, Tadahiro Sato1997 Volume 43 Issue 2 Pages 67-77
Published: July 25, 1997
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSWe are continuing experiments by using an Absolute Gravimeter with a Rotating Vacuum Pipe (AGRVP) at the Esashi Gravity Station (EGS), Iwate, Japan. We obtained about 8000 absolute gravity data for about one year from 1994 to 1995, and analyzed signals of the Earth tides in order to determine the amplitudes of gravity tidal variation absolutely. The absolute gravity data with a standard deviation of about 2×107-7ms-2can determine the amplitudes of the tidal gravity variation including the effects of ocean tides with an uncertainty of less than 0.5 percent. The difference between the observed and the theoretical Earth tides agrees with the oceanic gravity tides based on the Schwiderski's model within about 10 percent error.View full abstractDownload PDF (2420K) -
The Geographical, Yuzaburo Iimura, Satoshi Saga, Hitoshi Morishita, At ...1997 Volume 43 Issue 2 Pages 79-90
Published: July 25, 1997
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSIt is known that a phase measured by a GPS survey antenna is affected by the direction of the source of satellite radio waves. We previously measured this phasecharacteristics of several types of GPS surveying antennas. Recently, more advanced GPS surveying receivers have been used for surveys and geophysical observation. Wetherefore nce again carry out measurement tests on phase characteristics of the newtypes of antennas. This yields phase characteristics of the GPS antennas at the frequencyof Ll and L2 with respect to the azimuth and elevation angles. The differenceof phase characteristics between the same type of antennas and different types of antennas is also measured. Effects of frequency modification for code signals are also investigated by measuring phase characteristics on eight different frequencies, 1 and 10 MHz apart from L1 and L2. It is found that the variation of measured phases with the direction change of the radio source becomes a little amaller compared to those of the antennas used in the former experiments. This may be achieved by technical refinements of antennas.View full abstractDownload PDF (1110K) -
Toshiaki Tsujii, Masatoshi Harigae, Masaaki Murata1997 Volume 43 Issue 2 Pages 91-105
Published: July 25, 1997
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSA Kinematic GPS Software program (KINGS) has been developed at National Aerospace Laboratory (NAL), and its feasibility evaluated by flight experiments. Analysis of static data of the Izu-Islands area by KINGS shows that the positioning accuracy is around 1.5 cm horizontally, and 3 cm vertically. Data taken from the area on 6 th Oct. 1995 were also analyzed when an earthquake of M5.6 occurred near Kozujima Island. As a result, the movement of Kozujima Island eastward by a few centimeters was ob served. This suggests the possibility of the real time monitoring of crustal movement by kinematic GPS. In this paper, the on-the-fly ambiguity resolution algorithm which is requisite to the real time processing is described first, and the positioning accuracy of kinematic GPS is evaluated next. Finally, we demonstrate the movement of Kozujima Island before and afte the earthquake.View full abstractDownload PDF (1824K) -
Yoshio Sumino, Nagayoshi Katsuta, Hiromi Fujimaki, Natsuko Kondo, Shig ...1997 Volume 43 Issue 2 Pages 107-110
Published: July 25, 1997
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSSince 1992, geodetic measurements with GPS have been conducted in Matsumoto basin, Nagano Prefecture, central Japan. The Matsumoto basin is located on the Itoigawa-Shizuoka Tectonic Line, which is recently regarded as a plate boundary between the Eurasian plate and the North American plate. From the present GPS results of the Matsumoto basin, the principal strains measured at the northern area including the Omachi-city were a north-northwest contraction of 2.8±2.3×10-7/yr and an east-northeast extension of 1.9+2.7×10-7/yr during 1994-1996. While, at the southern area of the Matsumoto basin including the Matsumotocity, the principal strains measured there were a north-northwest extension of 2.8 t 1.8×10-7/yr and an eastnortheast extension of 0.6±1.2×10-7/yr during 1993-1996.View full abstractDownload PDF (3180K)
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