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Three-dimensional shear wave velocity structure in the upper mantle beneath the Philippine Sea region
Earth, Planets and Spacevolume 50, pages939–952 (1998)
The three-dimensional shear wave velocity structure in the upper mantle beneath the Philippine Sea was investigated with Rayleigh wave phase velocities in the periods 30–100 s. More than 900 Rayleigh wave phase velocity curves were obtained for this region with good path coverage. The phase velocity data were inverted for the phase velocity distribution maps in the Philippine Sea with 2-D tomographic technique without any a priori regionalization. The resolutions of the tomographic analysis were quite good in almost of the target region. The phase velocity maps were inverted for the 3-D shear wave velocity structure in the upper mantle down to 220 km.
In the shallow depths lateral heterogeneities with short wavelength were seen in the shear wave velocity maps. This might be related with complicated surface structures. In the middle depths the shear wave velocity was well correlated to the main tectonic features seen at the surface and well explained by the evolution history of the Philippine Sea. The older western Philippine Sea had higher shear wave velocities than the younger eastern Philippine Sea. In the western Philippine Sea the central basin ridge, which is the youngest in this area, showed the low velocity anomaly. This is supported by the fact that the West Philippine Basin was formed in this area. In the depths 150–200 km the low velocity anomaly was dominant inside the Philippine Sea, which might suggest the existence of the mantle return flows. The thickness of the lithosphere in the south of the West Philippine Basin reached about 100 km, which is much thicker than the results of previous studies for this region.
Akaike, H., Likelihood and Bayes procedure, in Bayesian Statistics, edited by J. M. Bernado et al., pp. 141–166, Univ. Press, Valencia, Spain, 1980.
Cara, M., Filtering of dispersed wavetrains, Geophys. J. R. astr. Soc., 33, 65–80, 1973.
Dziewonski, A. M. and D. L. Anderson, Preliminary reference Earth model, Phys. Earth Planet. Inter., 25, 297–356, 1981.
Dziewonski, A. M., A. L. Hales, and E. R. Lapwood, Parametrically simple Earth models consistent with geophysical data, Phys. Earth Planet. Inter., 10, 12–48, 1975.
Ekström, G., J. Tromp, and E. W. F. Larson, Measurements and global models of surface wave propagation, J. Geophys. Res., 102, 8137–8158, 1997.
Iidaka, T., K. Suyehiro, and H. Kinoshita, Lateral heterogeneity of the upper mantle velocity structure in the northern Philippine Sea basin, J. Phys. Earth, 37, 147–153, 1989.
Kanamori, H. and K. Abe, Deep structure of island arcs as revealed by the surface waves, Bull. Earthq. Res. Inst. Univ. Tokyo, 86, 1001–1025, 1968.
Kato, M. and T. H. Jordan, Seismic structure of the upper mantle beneath the Western Philippine Sea, Phys. Earth Planet. Inter., 1998 (submitted).
Kono, Y. and T. Yoshii, Numerical experiment on the thickening plate model, J. Phys. Earth, 23, 63–75, 1975.
Lebedev, S., G. Nolet, and R. D. van der Hilst, The upper mantle beneath the Philippine Sea region from waveform inversions, Geophys. Res. Lett., 24, 1851–1854, 1997.
Masters, G., T. H. Jordan, P. G. Silver, and F. Gilbert, Aspherical Earth structure from fundamental spheroidalmode data, Nature, 298, 609–613, 1982.
Mooney, W. D., G. Laske, and T. G. Masters, CRUST 5.1: A global crustal model at 5° × 5°, J. Geophys. Res., 103, 727–747, 1998.
Murauchi, S., N. Den, S. Asano, H. Hotta, T. Yoshii, T. Asanuma, K. Hagiwara, K. Ichikawa, T. Sato, W. J. Ludwig, J. I. Ewing, N. T. Edgar, and R. E. Houtz, Crustal structure of the Philippine Sea, J. Geophys. Res., 73, 3143–3171, 1968.
Nataf, H. C., I. Nakanishi, and D. L. Anderson, Measurements of mantle wave velocities and inversion for lateral heterogeneities and anisotropy, J. Geophys. Res., 91, 7261–7307, 1986.
Oda, H. and N. Senna, Regional variation of surface wave group velocities in the Philippine Sea, Tectonophys., 233, 265–277, 1994.
Saito, M., DISPER80: A subroutine package for the calculation of seismic normal mode solutions, in Seismological Algorithms, edited by D. J. Doornbos, pp. 293–319, Academic Press, San Diego, 1988.
Seekins, L. C. and T. Teng, Lateral variations in the Structure of the Philippine Sea Plate, J. Geophys. Res., 82, 317–325, 1977.
Senna, N., H. Oda, and K. Seya, Regional variation of Rayleigh wave group velocities in the Philippine Sea Area, Zisin, 43, 91–100, 1990 (in Japanese with English abstract).
Seno, T. and S. Maruyama, Paleogeographic reconstruction and organ of the Philippine Sea, Tectonophys., 102, 53–84, 1984.
Shiono, K., I. S. Sacks, and A. T. Linde, Preliminary velocity structure of Japanese Islands and Philippine Sea from surface wave dispersion, Carnegie Inst. Washington Year Book, 79, 498–505, 1980.
Suetsugu, D. and I. Nakanishi, Three-dimensional velocity map of the upper mantle beneath the Pacific Ocean as determined from Rayleigh wave dispersion, Phys. Earth Planet. Inter., 47, 205–229, 1987.
Tarantola, A. and B. Valette, Generalized non-linear inverse problems solved using the least squares criterion, Rev. Geophys. Space Phys., 20, 219–232, 1982.
Trampert, J. and J. H. Woodhouse, Global phase velocity maps of Love and Rayleigh waves between 40 and 150 seconds, Geophys. J. Int., 123, 675–690, 1995.
Trampert, J. and J. H. Woodhouse, High resolution global phase velocity distributions, Geophys. Res. Lett., 23, 21–24, 1996.
Xu, Y. and D. A. Wiens, Upper mantle structure of the southwest Pacific from regional waveform inversion, J. Geophys. Res., 102, 27439–27453, 1997.
Zhang, Y. S. and T. Lay, Global surface wave phase velocity variations, J. Geophys. Res., 101, 8415–8436, 1996.