The Spectrum of Torsional Oscillations of the Moon
Tóm tắt
The diagnostic potentialities of the torsional oscillations for probing the structure of the interiors of the Moon are investigated. Models with no core, a liquid core, and a solid core are considered. The profiles of compressional and shear wave velocities V
P and V
S for the lunar interior estimated by Bills and Ferrari (1977), Goins et al. (1981), and Nakamura (1983) from the Apollo lunar seismic network are used. For all these models, the periods of torsional oscillations for n = 2–100 and four overtones have been calculated. The derivatives of the dimensionless eigenfrequency with respect to the dimensionless shear modulus and density are calculated and tabulated for use. These data can be used to determine corrections to the model density and shear modulus distributions due to their small change. The damping of torsional oscillations is studied. Several trial radial distributions of the dissipative function Q are considered.
Tài liệu tham khảo
Alterman, Z., Jarosch, H., and Pekeris, C.L., Oscillations of the Earth, Proc. R. Soc., 1959, vol. A259, pp. 80–95.
Bills, B.G. and Ferrari, A.J., A Lunar Density Model Consistent with Topographic, Gravitational, Librational, and Seismic Data, J. Geophys. Res., 1977, vol. 82, no. 8, pp. 1306–1314.
Bolt, B.A. and Derr, J.S., Free Bodily Vibrations of the Terrestrial Planets, Vistas Astron., 1969, vol. 11, pp. 69–102.
Carr, R.E. and Kovach, R.L., Toroidal Oscillations of the Moon, Icarus, 1962, vol. 1, no. 1, pp. 75–76.
Derr, J.S., Free Oscillations of New Lunar Models, Phys. Earth Planet. Inter., 1969, vol. 2, pp. 61–68.
Goins, N.R., Dainty, A.M., and ToksÖz, M.N., Lunar Seismology: The Internal Structure of the Moon, J. Geophys. Res., 1981, vol. 86, no. B7, pp. 5497–5501.
Hood, L.L., Mitchell, D.L., Lin, R.P., et al., Initial Measurements of the Lunar Induced Magnetic Dipole Moment Using Lunar Prospector Magnetometer Data, Geophys. Res. Lett., 1999, vol. 26, no. 15, pp. 2327–2330.
Jeans, J.H., The Propagation of Earthquake Waves, Proc. R. Soc., 1923, vol. A102, p. 554.
Konopliv, A.S., Binder, A.B., Hood, L.L., et al., Improved Gravity Field of the Moon from Lunar Prospector, Science, 1998, vol. 281, no. 5382, pp. 1476–1479.
Lognonné, Ph. and Mosser, B., Planetary Seismology, Surv. Geophys., 1993, vol. 14, pp. 239–302.
Nakamura, Y., Latham, G., Lammlein, D., et al., Deep Lunar Interior Inferred from Recent Seismic Data, Geophys. Res. Lett., 1974, vol. 1, no. 3, pp. 137–140.
Nakamura, Y., Seismic Velocity Structure of the Lunar Mantle, J. Geophys. Res., 1983, vol. 8, no. B1, pp. 677–686.
Takeuchi, H., Saitov, M., and Kobayashi, N., Free Oscillations of the Moon, J. Geophys. Res., 1961, vol. 66, no. 11, pp. 3895–3897.
ToksÖz, M.N., Dainty, A.M., Solomon, S.C., and Anderson, K.R., Structure of the Moon, Rev. Geophys. Space Phys., 1974, vol. 12, pp. 539–567.
Zharkov, V.N., Free Oscillations of the Earth: Damping, Izv. Akad. Nauk SSSR, Ser. Geofiz., 1962, no. 2, pp. 159–170.
Zharkov, V.N., Lyubimov, V.M., Movchan, A.A., and Movchan, A.I., Effect of the Shell Physical Parameters on the Periods of Torsional Oscillations of the Earth, Fiz. Zemli, 1967, vol. 2, pp. 3–12.
Zharkov, V.N., Pan'kov, V.A., Kalachnikov, A.A., and Osnach, A.I., Vvedenie v fiziku Luny (Introduction to Lunar Physics), Moscow: Nauka, 1969.
Zharkov, V.N., Interior Structure of the Earth and Planets, Switzerland: Harwood Academic Publ. Chur., 1986.
Zharkov, V.N., Molodensky, S.M., Brzezinski, A., et al., The Earth and Its Rotation, Heidelberg: Wichmann, 1996.