Shear-wave splitting analysis of later phases in southwest Japan —A lineament structure detector inside the crust—

Iidaka, Takashi

doi:10.1186/bf03351760

Cited by 8 publications

(7 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure 11 shows that the fast polarization directions in the crust are in the trend of north-south to northeastsouthwest. Iidaka (2003) determined the fast polarization directions by a splitting analysis of multiple-reflected shear waves within the crust and emphasized that the fast polarization directions of the crust were from north-south to northeast-southwest (see Fig. 11).…”

Section: Real Splitting Analysis Of Ps Phases On the Receiver Functionsmentioning

confidence: 99%

“…Thus, the fast polarization direction of the shear wave is expected to be in the same direction as the maximum principal stress. But Iidaka (2003) reported by the splitting analysis of two phases reverberated in the crust that the fast polarization directions were inconsistent with the maximum principal stress direction in southwest Japan. This result may arise because the seismic phases analyzed in Iidaka's study were not clear enough to apply the splitting analysis.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Receiver Functions of Seismic Waves in Layered Anisotropic Media: Application to the Estimate of Seismic Anisotropy

Nagaya

Oda

Akazawa

et al. 2008

Bulletin of the Seismological Society of America

View full text Add to dashboard Cite

We investigate the effect of seismic anisotropy on P-wave receiver functions, calculating synthetic seismograms for P-wave incidence on multilayered anisotropic structure with hexagonal symmetry. The main characteristics of the receiver functions affected by the anisotropy are summarized as (1) appearance of seismic energy on radial and transverse receiver functions, (2) systematic change of P-to-S (Ps) converted waveforms on receiver functions as ray back-azimuth increases, and (3) reversal of the Ps-phase polarity on the radial receiver function in a range of the back azimuth. Another important influence is shear-wave splitting of the Ps-converted waves and other later phases reverberated as S wave. By numerical experiments using synthetic receiver functions, we demonstrate that the waveform cross-correlation analysis is applicable to splitting Ps phases on receiver functions to estimate the seismic anisotropy of layer structure. Advantages to utilizing the Ps phases are (1) they appear more clearly on receiver functions than on seismograms and (2) they inform us about what place along the seismic ray path is anisotropic. Real analysis of shear-wave splitting is executed to the Moho-generated Ps phases that are identified on receiver functions at six seismic stations in the Chugoku district, southwest Japan. The time lags between the two arrivals of the split Ps phases are estimated at 0.2-0.7 sec, and the polarization directions of the fast arrival components are from north-south to northeast-southwest. This result is consistent with recent results of shear-wave splitting measurements and the trend of linear epicenter distributions of crustal earthquakes and active fault strikes in the Chugoku district.

show abstract

Section: Real Splitting Analysis Of Ps Phases On the Receiver Functionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Receiver Functions of Seismic Waves in Layered Anisotropic Media: Application to the Estimate of Seismic Anisotropy

Nagaya

Oda

Akazawa

et al. 2008

Bulletin of the Seismological Society of America

View full text Add to dashboard Cite

show abstract

“…Shear wave splitting observations are a straight‐forward and powerful method to study the anisotropy of the crust and mantle [e.g., Maupin and Park , 2007; Savage , 1999; Silver , 1996]. Seismic anisotropy of the crust and upper mantle beneath SW Japan has been revealed by shear wave splitting measurements [e.g., Iidaka , 2003; Salah et al , 2008]. Although shear wave splitting measurements can provide useful information for characterizing the upper mantle deformation, the interpretation of the results in a subduction zone is very difficult because of the existence of complex 3‐D mantle flow [ Long and Silver , 2008] and different contributions of the minerals and hydrous phases [ Mainprice and Ildefonse , 2009].…”

Section: Introductionmentioning

confidence: 99%

P wave anisotropic tomography of the Nankai subduction zone in Southwest Japan

Wang

Zhao

2012

Geochem Geophys Geosyst

View full text Add to dashboard Cite

[1] The active subduction of the young Philippine Sea (PHS) plate and the old Pacific plate has resulted in significant seismic heterogeneity and anisotropy in Southwest (SW) Japan. In this work we determined a detailed 3-D P wave anisotropic tomography of the crust and upper mantle beneath SW Japan using $540,000 P wave arrival times from 5,249 local earthquakes recorded by 1095 stations. The PHS slab is imaged clearly as a high-velocity (high-V) anomaly which exhibits considerable lateral variations. Significant low-velocity (low-V) anomalies are revealed above and below the PHS slab. The low-V anomalies above the PHS slab may reflect the upwelling flow in the mantle wedge and the PHS slab dehydration, and they form the source zone of the arc volcanoes in SW Japan. The low-V zones under the PHS slab may reflect the upwelling flow in the big mantle wedge above the Pacific slab. The anisotropy in the crust and upper mantle is complex. In Kyushu, the P wave fast velocity direction (FVD) is generally trenchnormal in the mantle wedge under the back-arc, which is consistent with the corner flow driven by the PHS slab subduction. The FVD is trench-parallel in the subducting PHS slab under Kyushu. We think that the intraslab seismicity is a potential indicator to the slab anisotropy. That is, the PHS slab with seismicity has kept its original fossil anisotropy formed at the mid-ocean ridge, while the aseismic PHS slab has reproduced the anisotropy according to its current deformation.

show abstract

“…In addition, there are other contributions from converted/reflected phases in the crust that can mask this particular arrival. Nevertheless, this is an often-utilized procedure (e.g., McNamara and Owens 1993;Iidaka 2003;Rai et al 2008) that continues to yield consistent characteristics for crustal splitting, namely delay times averaging about 0.2 s.…”

Section: Array Datamentioning

confidence: 99%

“…However, if converted phases such as Ps, P410s, or P660s with good waveform clarity and high signal-to-noise ratio (SNR) can be indentified on seismic records, they can be subjected to splitting analysis and the results can be used to place some depth constraints on the responsible anisotropy. Of course, detection of such phases with sufficient SNR can be difficult, but a few studies have looked at splitting above the Moho or above the 660 km transition using converted phases (e.g., Iidaka and Niu 1998;Iidaka 2003) have been carried out. Measurements of shear wave splitting on phases converted at the Moho provide constraints on crustal anisotropy at the frequencies of interest (e.g., McNamara et al 1994;Herquel et al 1995;Ozacar and Zandt 2004), which is not only interesting in its own right, but can also be used to ''correct'' shear wave splitting measurements for the effect of crustal anisotropy and isolate the contribution from the mantle.…”

Section: The Use Of Reflected and Converted Phasesmentioning

confidence: 99%

Shear Wave Splitting and Mantle Anisotropy: Measurements, Interpretations, and New Directions

2009

View full text Add to dashboard Cite

Measurements of the splitting or birefringence of seismic shear waves that have passed through the Earth's mantle yield constraints on the strength and geometry of elastic anisotropy in various regions, including the upper mantle, the transition zone, and the D 00 layer. In turn, information about the occurrence and character of seismic anisotropy allows us to make inferences about the style and geometry of mantle flow because anisotropy is a direct consequence of deformational processes. While shear wave splitting is an unambiguous indicator of anisotropy, the fact that it is typically a near-vertical path-integrated measurement means that splitting measurements generally lack depth resolution. Because shear wave splitting yields some of the most direct constraints we have on mantle flow, however, understanding how to make and interpret splitting measurements correctly and how to relate them properly to mantle flow is of paramount importance to the study of mantle dynamics. In this paper, we review the state of the art and recent developments in the measurement and interpretation of shear wave splitting-including new measurement methodologies and forward and inverse modeling techniques,-provide an overview of data sets from different tectonic settings, show how they help us relate mantle flow to surface tectonics, and discuss new directions that should help to advance the shear wave splitting field.

show abstract

Shear-wave splitting analysis of later phases in southwest Japan —A lineament structure detector inside the crust—

Cited by 8 publications

References 18 publications

Receiver Functions of Seismic Waves in Layered Anisotropic Media: Application to the Estimate of Seismic Anisotropy

Receiver Functions of Seismic Waves in Layered Anisotropic Media: Application to the Estimate of Seismic Anisotropy

P wave anisotropic tomography of the Nankai subduction zone in Southwest Japan

Shear Wave Splitting and Mantle Anisotropy: Measurements, Interpretations, and New Directions

Contact Info

Product

Resources

About