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Volume 44 (1993)
- Issue 4 Pages 105-
- Issue 3 Pages 73-
- Issue 2 Pages 39-
- Issue 1 Pages 1-
Volume 44, Issue 2
Displaying 1-3 of 3 articles from this issue
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Hirotada Kanehisa1993 Volume 44 Issue 2 Pages 39-44
Published: 1993
Released on J-STAGE: October 20, 2006
JOURNAL FREE ACCESSThe Q-vector in a quasigeostrophic system (Hoskins et al. 1978), which represents the tendency of geostrophic flows to destroy their own geostrophic balance, is a useful tool in diagnosing ageostrophic circulations. Recently, a 3-dimensional extension of the Q-vector was obtained in a quasigeostrophic system, and it was termed the C-vector (Xu 1992). On the other hand, the Q-vector was generalized into a primitive system (Davies-Jones 1991) and an ageostrophic circulation equation which is similar to the Q-vector equation in a quasigeostrophic system was obtained.
In this note, in an f-plane, a 3-dimensional thermal-wind imbalance vector, which is the curl of the body force vector, is introduced. By equating the material derivative of the 3-dimensional thermal-wind imbalance vector to zero, the C-vector equations in semigeostrophic and primitive systems are derived.View full abstractDownload PDF (433K) -
Hidekazu Matsueda1993 Volume 44 Issue 2 Pages 45-56
Published: 1993
Released on J-STAGE: October 20, 2006
JOURNAL FREE ACCESSWe developed an automated GC/FID analysis system to determine methane mixing ratios of standard gases with a mean precision of ±0.12%. The GC/FID analysis of five gravimetric standards showed that their methane scale was stable and internally consistent. However, the diluent air for these standards had a small amount of methane, which was estimated to be 35.5 ppb. Thus, our MRI/GRL scale was corrected for methane impurity in the diluent air.
The methane mixing ratio of dry natural air in an aluminum cylinder prepared for the intercalibration experiment was determined to be 1.7545±0.0015 ppm on the basis of the MRI/GRL scale. This mixing ratio was higher by 23.0 ppb than that assigned by NOAA/CMDL. This difference indicated that the offset of 23.0 ppb between NOAA/CMDL and MRI/GRL scales will need to be taken into account when methane data from both laboratories are compared.View full abstractDownload PDF (994K) -
Akio Katsumata1993 Volume 44 Issue 2 Pages 57-71
Published: 1993
Released on J-STAGE: October 20, 2006
JOURNAL FREE ACCESSEarthquake swarm activities have occasionally occurred in the offshore region to the northeast of the Izu Peninsula since 1978. Anomalous crustal deformation has also continued around the northeast part of the Izu Peninsula since 1978. Earthquake swarm activities started on June 30 in 1989, and peaked on July 4. A volcanic tremor started on July 11, and a submarine eruption followed on July 13. The largest earthquake (M5.5) in the 1989 swarm activities occurred on July 9. It was the second largest earthquake among the swarm activities since 1978. Tensile fault models have been proposed to interpret the ground deformation and the earthquake swarm activities in 1989. It has been estimated that magma intrusion had been most active from July 4 till July 11. The largest earthquake took place when magma was intruding, and it was located near the site of the submarine eruption. We checked up on the location of the earthquake to estimate the effect of the intrusion on earthquake initiation. We compared observed strong motion records with synthetics which were computed for various starting points of rupture on the assumed fault, and checked the initial motion polarities observed with seismographs around the inferred earthquake fault. It was estimated that the epicenter of the earthquake was apart from the vent of the eruption, and that the fracture started at the bottom of the fault.View full abstractDownload PDF (1166K)
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