Lunar gravity: A mass point model

Ananda, M. P.

doi:10.1029/jb082i020p03049

Cited by 32 publications

(13 citation statements)

References 17 publications

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“…However, we believe there are strong indications of mascons for six large farside basins as listed in Table II. Most of these features have been identified before as negative anomalies (Ananda 1977, Konopliv et al 1993. However, in the LP models it has become apparent that these features also have a central gravity high in the center of the basin with a surrounding negative ring.…”

Section: Figmentioning

confidence: 94%

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Recent Gravity Models as a Result of the Lunar Prospector Mission

Konopliv

Asmar

Carranza

et al. 2001

Icarus

326

256

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Section: Figmentioning

confidence: 94%

“…From these data as well as tracking data from the Apollo Command Service Modules (CSM), many additional line-of-sight analyses were performed (e.g., Phillips et al (1972) on the Serenitatis mascon) in addition to surface mass distribution models by Wong et al (1971) and Ananda (1977).…”

Section: Introductionmentioning

confidence: 99%

Recent Gravity Models as a Result of the Lunar Prospector Mission

Konopliv

Asmar

Carranza

et al. 2001

Icarus

326

256

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“…This seismic model can then be interpreted in conjunction with other geophysical data, such as magnetic sounding (Parkin et al, 1973;Duba and Ringwood, 1973;Olhoeft et al, 1974;Dyal et al, 1974Dyal et al, , 1975Dyal et al, , 1976Piwinskii and Duba, 1975;Vanyan and Egorov, 1977;Schwerer et al, 1974;Wiskerchen and Sonett, 1927), gravity and topographic figure analyses (Kaula, 1971(Kaula, , 1975bKaula et al, 1974;Runcorn, 1975;Bills and Ferrari, 1977;Ananda, 1977;Ferrari, 1977;Thurber and Solomon, 1978;Vermillion, 1976) and average density and moment of inertia values (Blackshear and Gapcynski, 1977;Solomon, 1974;Solomon and Toksbz, 1973;Michael and Blackshear, 1972;Gast and Guili, 1972) so that the final structural model is compatible with all information.…”

mentioning

confidence: 99%

Lunar seismology: The internal structure of the Moon

Goins¹,

Dainty²,

Toksöz³

1981

J. Geophys. Res.

147

104

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Tables A1–A4 and Figures A1–A3 are available with entire articleon microfiche. Order from American Geophysical Union, 2000 Florida Avenue, N.W., Washington, D.C. 20009. Document J81‐003;$1.00. Payment must accompany order. The arrival times of direct P and S waves, measured on seismograms recorded from natural lunar seismic events, have been analyzed using linearized inversion and parameter search methods to simultaneously determine event locations, origin times, and structural parameters (seismic velocities). Polarization‐filtered record section plots are correlated with theoretical travel time curves to identify later phases and obtain additional structural and velocity information. Shear wave amplitudes plotted as a function of distance provide data on the existence and magnitude of seismic velocity gradients in the interior. These studies are used to delineate the structure of the moon below the crust to a depth of about 1100 km. This structure has been divided into an upper and a lower mantle. The upper mantle, from 60‐ to 400‐km depth, has average seismic wave velocities of Vp = 7.70 ±0.15 km/s and Vs = 4.45 ± 0.05 km/s with corresponding Q values (taken from the literature) of Qp ∼ 5000 and Qs ∼ 3000. The shear wave velocity decreases with a negative gradient of at most −6 × 10−4 km/s/km, implying a Vs variation of from 4.57 km/s at 60‐km depth to 4.37 km/s at 400‐km depth; this decrease can be accounted for by increasing temperature, and so no major compositional gradient is required in the upper mantle. A small negative P wave velocity gradient may also be present. Between 400‐ and 480‐km depth there is a transition zone with a sharply decreasing shear wave velocity and possibly an accompanying small decrease in Vp. The dominant shear velocity decrease may occur at a 480‐km interface and may represent a compositional change, although the effects of increased temperature cannot be totally ruled out. The lower mantle extends from 480‐km depth to at least 1100‐km depth; few seismic waves recorded by the lunar network penetrate below 1100 km. The average velocities are Vp = 7.6 ± 0.6 km/s and Vs = 4.2 ± 0.1 km/s. Q values (taken from the literature) are Qp ∼ 1500 and Qs ∼ 1000. Below 1100 km there is some indication that the attenuation may increase still further for shear waves, with Qs dropping to a few hundreds or less. This seismic model of the moon is well constrained, with uncertainties on the above values given explicitly by the analysis methods, and so it serves as a strong control on the present‐day lunar compositional and thermal structure.

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“…1) and density of 3.0 g/cm3, no isostatic compensation appears to exist. Recent studies of long-term perturbations in the or bits of lunar satellites has resulted in gravity maps of the far side (Ferrari, 1975;Ananda, 1975). These maps generally show negative anomalies to be associated with multiringed basins; thus they represent mass deficiencies rather than mascons.…”

Section: Gravity and Geologic Structurementioning

confidence: 99%