start-ver=1.4
cd-journal=joma
no-vol=11
cd-vols=
no-issue=1
article-no=
start-page=1
end-page=5
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2004
dt-pub=20041231
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=重力異常データのカラムインバージョンから見積もったモホ不連続面の形状
kn-title=Topography of the Moho discontinuity estimated by column inversion of gravity anomaly data
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=We present an inversion method, called "column inversion", to retrieve two-dimensional variation of the depth to the Moho discontinuity from Bouguer gravity anomaly data, assuming that a density jump between the lower crust and upper mantle is regionally invariant. The inversion method is applied to reveal the apatial undulation of the Moho discontinuity in the Chugoku and Shikoku districts, southwest Japan. The result shows that the Moho is deep in the land area and shallow in the sea area. The Moho is anomalously deep in the west regions of Shikoku and Chugoku districts, where the prominent negative gravity anomaly is observed. The two-dimensional variation of the Moho depth is quite similar to that determined by inversion of the first P-arrival time data. The column inversion of the Bouguer gravity anomaly data is proved to be useful for determining the fine structure of the Moho discontinuity undulation.
en-copyright=
kn-copyright=

en-aut-name=FukunagaMariko
en-aut-sei=Fukunaga
en-aut-mei=Mariko
kn-aut-name=福永真理子
kn-aut-sei=福永
kn-aut-mei=真理子
aut-affil-num=1
ORCID=

en-aut-name=OdaHitoshi
en-aut-sei=Oda
en-aut-mei=Hitoshi
kn-aut-name=小田仁
kn-aut-sei=小田
kn-aut-mei=仁
aut-affil-num=2
ORCID=

en-aut-name=ShichiRyuichi
en-aut-sei=Shichi
en-aut-mei=Ryuichi
kn-aut-name=志知竜一
kn-aut-sei=志知
kn-aut-mei=竜一
aut-affil-num=3
ORCID=

affil-num=1
en-affil=
kn-affil=Department of Earth Sciences, Okayama University

affil-num=2
en-affil=
kn-affil=Department of Earth Sciences, Okayama University

affil-num=3
en-affil=
kn-affil=Faculty of Engineering, Chubu University
en-keyword=Bouguer Gravity Anomaly
kn-keyword=Bouguer Gravity Anomaly
en-keyword=Column Inversion
kn-keyword=Column Inversion
en-keyword=Moho Discontinuity
kn-keyword=Moho Discontinuity
en-keyword=Chugoku and Shikoku Districts
kn-keyword=Chugoku and Shikoku Districts
END

start-ver=1.4
cd-journal=joma
no-vol=10
cd-vols=
no-issue=1
article-no=
start-page=11
end-page=14
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2003
dt-pub=20031220
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Elasticity of diopside CaMgSi(2)O(6) measured by means of the resonant sphere technique, RST
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=Resonant frequencies for a single crystad diopside sphere are measured accurately and rhirteen elastic moduli are reluced by the least squares calculation, A set of mduli gives theoretical resonant frequencies close enough to the observed ones.
en-copyright=
kn-copyright=

en-aut-name=SuzukiIsao
en-aut-sei=Suzuki
en-aut-mei=Isao
kn-aut-name=鈴木功
kn-aut-sei=鈴木
kn-aut-mei=功
aut-affil-num=1
ORCID=

en-aut-name=InouyeYasushi
en-aut-sei=Inouye
en-aut-mei=Yasushi
kn-aut-name=井上靖
kn-aut-sei=井上
kn-aut-mei=靖
aut-affil-num=2
ORCID=

en-aut-name=OdaHitoshi
en-aut-sei=Oda
en-aut-mei=Hitoshi
kn-aut-name=小田仁
kn-aut-sei=小田
kn-aut-mei=仁
aut-affil-num=3
ORCID=

en-aut-name=MoriokaMasana
en-aut-sei=Morioka
en-aut-mei=Masana
kn-aut-name=森岡正名
kn-aut-sei=森岡
kn-aut-mei=正名
aut-affil-num=4
ORCID=

affil-num=1
en-affil=
kn-affil=Department of Earth Science, Okayama University

affil-num=2
en-affil=
kn-affil=Department of Earth Science, Okayama University

affil-num=3
en-affil=
kn-affil=Department of Earth Science, Okayama University

affil-num=4
en-affil=
kn-affil=The Isotope Center, University of Tokyo
en-keyword=diopside
kn-keyword=diopside
en-keyword=single crystal
kn-keyword=single crystal
en-keyword=resonace
kn-keyword=resonace
en-keyword=sphere
kn-keyword=sphere
en-keyword=elasticity
kn-keyword=elasticity
END

start-ver=1.4
cd-journal=joma
no-vol=7
cd-vols=
no-issue=1
article-no=
start-page=15
end-page=18
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2000
dt-pub=20000920
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=S-wave velocity structure estimated from long-period coda waves
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=Long-period coda waves were recorded on the vertical-component seismograms of aftershocks of the Hyogo-ken Nanbu earthquake, 1995. We identify the long-period coda waves as Rayleigh wave, because they appear after the S-arrival times and exhibit the normal dispersion that propagation velocity of the coda waves increases with an increase in period. By applying the moving window analysis to the coda waves from nine aftershocks, the group velocities are determined as a function of period within the range of 2 to 8 s. The group velocity dispersion data are inverted to investigate the S-wave velocity structure of the upper crust. The S-wave velocity structure is consistent with those obtained in previous studies using traval time analysis of bood waves.
en-copyright=
kn-copyright=

en-aut-name=OdaHitoshi
en-aut-sei=Oda
en-aut-mei=Hitoshi
kn-aut-name=小田仁
kn-aut-sei=小田
kn-aut-mei=仁
aut-affil-num=1
ORCID=

en-aut-name=
en-aut-sei=
en-aut-mei=
kn-aut-name=ItoAki
kn-aut-sei=Ito
kn-aut-mei=Aki
aut-affil-num=2
ORCID=

affil-num=1
en-affil=
kn-affil=Department of Earth Sciences, Okayama University

affil-num=2
en-affil=
kn-affil=Observation Center for Prediction of Earthquakes and Volcanic Eruptions, Tohoku University
en-keyword=surface wave dispersion
kn-keyword=surface wave dispersion
en-keyword=coda wave
kn-keyword=coda wave
en-keyword=S-wave velocity structure
kn-keyword=S-wave velocity structure
en-keyword=upper crust
kn-keyword=upper crust
en-keyword=Hyogo-ken
kn-keyword=Hyogo-ken
END

start-ver=1.4
cd-journal=joma
no-vol=4
cd-vols=
no-issue=1
article-no=
start-page=1
end-page=20
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=1997
dt-pub=19970920
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=Three-dimensional structure of P wave velocity in the crust and upper mantle beneath southwest Japan
kn-title=西南日本の地殻及び上部マントルの三次元P波速度構造
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=Trevel-time data of the P wave were inverted to study three-dimensional structure of the P wave velocity in the upper mantle and crust beneath the Shikoku and Chugoku districts, southwest Japan. Low-velocity and high-velocity regions were found in the upper crust of the eastrn and western regions in the Shikoku district, respectively. The activity of crustal earthquakes is high in the eastern region. Moreover a significant high-velocity region exists in the uppermost mantle, where the activity of small earthquakes is very high. A low-velocity region with velocity of 7.0km/s was found just above the descending Philippine Sea plate with high velocity of 8.0 km/s. This region is continued to oceanic crust in the vicinity of the Nankai trough and its velocity is nearly equal to the P wave velocity (6.7 km/s) of oceanic crust. Thus the low velocity is interpreted as the oceanic crust. A high-velocity region is found below the depth of 50km in the Shikoku district. This region suggests the Philippine sea plate lying horizontally from the Shikoku districts to the ocast of the Seto Inland Sea of the Chugoku district. A low-velocity zone suggesting the volcanic front is found around the depth of 50km at the coast of the Japan Sea of the Chugoku distrit.
en-copyright=
kn-copyright=

en-aut-name=TanakaTakashi
en-aut-sei=Tanaka
en-aut-mei=Takashi
kn-aut-name=田中猛士
kn-aut-sei=田中
kn-aut-mei=猛士
aut-affil-num=1
ORCID=

en-aut-name=OdaHitoshi
en-aut-sei=Oda
en-aut-mei=Hitoshi
kn-aut-name=小田仁
kn-aut-sei=小田
kn-aut-mei=仁
aut-affil-num=2
ORCID=

affil-num=1
en-affil=
kn-affil=

affil-num=2
en-affil=
kn-affil=岡山大学理学部地球学科
en-keyword=Three-dimenrsional structure
kn-keyword=Three-dimenrsional structure
en-keyword=P wave
kn-keyword=P wave
en-keyword=Crust
kn-keyword=Crust
en-keyword=Upper mantle
kn-keyword=Upper mantle
en-keyword=Philippine Sea plate
kn-keyword=Philippine Sea plate
END

start-ver=1.4
cd-journal=joma
no-vol=3
cd-vols=
no-issue=1
article-no=
start-page=33
end-page=42
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=1996
dt-pub=19960920
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=Inversion of normal mode frequencies for estimation of lateral heterogeneity of the earth's elasticity atructure: A numerical test
kn-title=固有周波数のインバージョンによる地球内部構造の不均質性の推定 　―数値実験―
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=An investigation was made on effect of lateral heterogenity of the earth's elasticity structure on the normal mode frequencies. The lateral heterogeneity is expressed by an expansion of spherical harmonic functions, Pιm(cosθ)sinmΦ and Pιm(cosθ)cosmΦ, up to the second order harmonics (ι?2). Free oscillation freguencies of the heterogeneous earth were computed by the xyz algorithm. Further we derived an analytic expression of partial derivatives of eigenfrequency with respect to the expansion coefficients, and performed a numerical test to verify whether or not it is possible to estimate the heterogeneity of the earth's structure by the inversion of noemal mode frequencies.
 When the earth is assumed to be elastically isotropic spheroid with short polar and long equatorial radii, frequency spectra affected by longitudinal heterogeneity terms, Pιm(cosθ)(sinmΦ, cosmΦ) (m≠ 0), for given values of ι and m coincide with each other, because these two terms describe the same heterogeneity when the earth is rotated by π/2m around rotation axis. In such a case, we cannot determine accurately the expansion coefficients of tha two heterogeneity terms by inversion of normal mode frequencies, whereas the coefficients of the latitudinal heterogeneity Pι0(cosθ) can be precisely determined. Therefore it is difficult to estimate of lateral heterogeneity of the earth's elasticity structure by the inversion of normal mode frequencies.
en-copyright=
kn-copyright=

en-aut-name=OnishiSeiji
en-aut-sei=Onishi
en-aut-mei=Seiji
kn-aut-name=大西星司
kn-aut-sei=大西
kn-aut-mei=星司
aut-affil-num=1
ORCID=

en-aut-name=OdaHitoshi
en-aut-sei=Oda
en-aut-mei=Hitoshi
kn-aut-name=小田仁
kn-aut-sei=小田
kn-aut-mei=仁
aut-affil-num=2
ORCID=

affil-num=1
en-affil=
kn-affil=岡山大学大学院理学研究科

affil-num=2
en-affil=
kn-affil=岡山大学理学部地球科学科
en-keyword=Normal Mode
kn-keyword=Normal Mode
en-keyword=Inversion
kn-keyword=Inversion
en-keyword=Earth's Structure
kn-keyword=Earth's Structure
en-keyword=Lateral Heterogeneity
kn-keyword=Lateral Heterogeneity
END

start-ver=1.4
cd-journal=joma
no-vol=1
cd-vols=
no-issue=1
article-no=
start-page=19
end-page=26
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=1994
dt-pub=19940920
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=ScSp Phase observed on the Coast of the Seto Inland Sea
kn-title=瀬戸内海沿岸で観測されたScSp相について
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=Observation of ScSp phase, P wave converted from ScS phase, has been made at a seismological observatory (SBK) located on the coast of the Seto Inland Sea, southwest Japan. The ScSp phases were found on the seismograms of earthqukes with long epicentral distances, but not observed for those with short epicentral distances. Such dependence of appearance of the ScSp phase on epientral distance is interpreted as being due to the Philippine Sea plate horizontally lying beneath the Shikoku and Chugoku districts.
en-copyright=
kn-copyright=

en-aut-name=NishiMasaki
en-aut-sei=Nishi
en-aut-mei=Masaki
kn-aut-name=西政樹
kn-aut-sei=西
kn-aut-mei=政樹
aut-affil-num=1
ORCID=

en-aut-name=OdaHitoshi
en-aut-sei=Oda
en-aut-mei=Hitoshi
kn-aut-name=小田仁
kn-aut-sei=小田
kn-aut-mei=仁
aut-affil-num=2
ORCID=

affil-num=1
en-affil=
kn-affil=Tottori Meteorological Obseruvatory

affil-num=2
en-affil=
kn-affil=Department of Earth Sicences, Okayama University
en-keyword=ScS Phase
kn-keyword=ScS Phase
en-keyword=ScSp Phase
kn-keyword=ScSp Phase
en-keyword=Philippine Sea Plate
kn-keyword=Philippine Sea Plate
en-keyword=Southwest Japan
kn-keyword=Southwest Japan
END

start-ver=1.4
cd-journal=joma
no-vol=22
cd-vols=
no-issue=1
article-no=
start-page=1
end-page=7
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2015
dt-pub=20151227
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=The effect of the seismic attenuation on the S-wave polarization anisotropy
kn-title=地震波の減衰がS 波偏向異方性に及ぼす影響
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=We investigate the effect of the seismic attenuation on the shear-wave polarization anisotropy by numerical experiments. For the experiments, the P-wave receiver functions are synthesized by assuming that a plane P wave is incident on an anisotropic multi-layer structure with anelastic properties. The synthetic receiver function shows smooth Ps phase waveforms with small amplitudes due to the attenuation of high-frequency spectral components, compared to that calculated for a multi-layer structure with perfect elasticity. From the shear-wave splitting of the Ps converted phases in the synthetic receiver functions, the S-wave polarization anisotropies for the anisotropic layers are measured as a function of propagation direction of the incident P wave. Consequently, we conclude that the seismic attenuation has a minor influence on the measurements of the S-wave polarization anisotropy.
en-copyright=
kn-copyright=

en-aut-name=OdaHitoshi
en-aut-sei=Oda
en-aut-mei=Hitoshi
kn-aut-name=小田仁
kn-aut-sei=小田
kn-aut-mei=仁
aut-affil-num=1
ORCID=

affil-num=1
en-affil=
kn-affil=岡山大学理学部地球科学科
en-keyword=shear-wave polarization anisotropy
kn-keyword=shear-wave polarization anisotropy
en-keyword=shear-wave splitting
kn-keyword=shear-wave splitting
en-keyword=seismic attenuation
kn-keyword=seismic attenuation
en-keyword=Psconverted phase
kn-keyword=Psconverted phase
en-keyword=P-wave receiver function
kn-keyword=P-wave receiver function
END