A new seismic velocity model for the Moon from a Monte Carlo inversion of the Apollo lunar seismic data

Khan, A.; Mosegaard, Klaus; Rasmussen, Kaare Lund

doi:10.1029/1999gl008452

Cited by 137 publications

(136 citation statements)

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“…The Khan et al model differs significantly from previous seismic models (Goins et al 1981, Nakamura 1983 especially in the lower mantle. Figure 2 shows that the lower mantle seismic velocities reported by Khan et al (2000) are petrologically unfeasible because they are too large to be consistent with theoretical seismic velocities calculated for plausible lunar compositions, densities, and temperatures. The calculated field of the seismic velocities in the lunar mantle reservoirs as a function of density and composition shows that the maximum velocity values are not greater than 4.61-4.69 km s −1 for V s and 8.21-8.39 km s −1 for V p (Fig.…”

Section: Models Of Composition and Internal Structure Of The Moonmentioning

confidence: 66%

“…The lower mantle velocities of the Khan et al model (V p = 11.0 ± 2.1 and V s = 6.0 ± 0.7 km s −1 at a depth of about 800 km) are similar to those in the Earth's mantle at depths of 400-800 km (P = 13-30 GPa, ρ = 3.7-4.45 g cm −3 according to the "PREM" and "iasp91" models), and demand significantly larger densities than those in the lunar mantle. From the standpoint of lunar petrology, and of elasticity and density of minerals, there are insuperable objections to the seismic velocities proposed by Khan et al (2000) in the lunar lower mantle.…”

Section: Models Of Composition and Internal Structure Of The Moonmentioning

confidence: 94%

“…Recently Khan et al (2000) have reported a reinvestigation of the Apollo lunar seismic data using an inverse Monte-Carlo method. The Khan et al model differs significantly from previous seismic models (Goins et al 1981, Nakamura 1983 especially in the lower mantle.…”

Section: Models Of Composition and Internal Structure Of The Moonmentioning

confidence: 99%

“…Dotted lines-upper mantle (3.22 < ρ < 3.34 g cm −3 ); solid lines-middle mantle (3.29 < ρ < 3.44 g cm −3 ); dashed lines-lower mantle (3.34 < ρ < 3.52 g cm −3 ). Seismic velocity models of Nakamura (1983) and Khan et al (2000), not associated with densities, are shown for comparison: the Nakamura seismic data at depths of 60-270 km (1), 270-500 km (2), and 500-1000 km (3); the Khan et al (2000) seismic and model at depths of 45-500 km (4), 500-560 km (5), 560-600 km (6), and ≥ 780 km (7). tion satisfies the bulk Moon derived from the totality of geophysical constraints.…”

Section: Figmentioning

confidence: 99%

See 3 more Smart Citations

Core Sizes and Internal Structure of Earth's and Jupiter's Satellites

Kuskov

Kronrod

2001

Icarus

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Section: Models Of Composition and Internal Structure Of The Moonmentioning

confidence: 66%

Section: Models Of Composition and Internal Structure Of The Moonmentioning

confidence: 94%

Section: Models Of Composition and Internal Structure Of The Moonmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

See 2 more Smart Citations

Core Sizes and Internal Structure of Earth's and Jupiter's Satellites

Kuskov

Kronrod

2001

Icarus

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“…Khan et al [25] suggested that the crustal thickness was 45 ± 5 km in the Apollo zone (which is most representative of the Apollo 12 and 14 landing sites given the distribution of seismic events used in their analysis). In a subsequent analysis that tested the hypothesis of having a crust thinner than the Apollo-era analyses, they showed that models with thicker crusts had unrealistic P-wave velocity profiles and that a crustal thickness of 38 ± 3 was preferred [26].…”

Section: Thickness Of the Crustmentioning

confidence: 99%

Lunar bulk chemical composition: a post-Gravity Recovery and Interior Laboratory reassessment

Taylor

Wieczorek

2014

Phil. Trans. R. Soc. A.

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New estimates of the thickness of the lunar highlands crust based on data from the Gravity Recovery and Interior Laboratory mission, allow us to reassess the abundances of refractory elements in the Moon. Previous estimates of the Moon fall into two distinct groups: earthlike and a 50% enrichment in the Moon compared with the Earth. Revised crustal thicknesses and compositional information from remote sensing and lunar samples indicate that the crust contributes 1.13–1.85 wt% Al 2 O 3 to the bulk Moon abundance. Mare basalt Al 2 O 3 concentrations (8–10 wt%) and Al 2 O 3 partitioning behaviour between melt and pyroxene during partial melting indicate mantle Al 2 O 3 concentration in the range 1.3–3.1 wt%, depending on the relative amounts of pyroxene and olivine. Using crustal and mantle mass fractions, we show that that the Moon and the Earth most likely have the same (within 20%) concentrations of refractory elements. This allows us to use correlations between pairs of refractory and volatile elements to confirm that lunar abundances of moderately volatile elements such as K, Rb and Cs are depleted by 75% in the Moon compared with the Earth and that highly volatile elements, such as Tl and Cd, are depleted by 99%. The earthlike refractory abundances and depleted volatile abundances are strong constraints on lunar formation processes.

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Apollo 17 and the Moon

Schmitt

2003

Encyclopedia of Space Science and Technology

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Apollo 17 was not the last flight of humans to the Moon. More lunar exploration and even lunar settlement will occur, baring the future stagnation or disappearance of our civilization. Exploration and scientific investigations in the earth sciences are rarely complete, particularly for studies related to a specific field site. A long hiatus between field investigations may occur, but other forms of investigation, directly or indirectly related, continue. Apollo 17's field study of the Valley of Taurus‐Littrow on the Moon in 1972 and subsequent examination of its significance to our understanding of the origin and evolution of that small planet and of our own constitute a good example of these facts of scientific life. As the third of the specifically “science” missions to the Moon in the twentieth century, Apollo 17 actually became the last lunar landing of the Apollo Program in September 1970 rather than on 11 December 1972 when the mission reached Taurus‐Littrow. The National Aeronautics and Space Administration (NASA) and the Administration of President Richard M. Nixon, with the acquiescence of the Congress, had concluded that no further planned amortization of the American taxpayer's investment in deep space exploration would be undertaken. The scientists became increasingly interested in an unnamed, 2300‐m deep, 50‐km long valley, radial to the 740‐km diameter circular basin, Serenitatis, that cut through the Taurus Mountain ring near the crater Littrow. This Valley of “Taurus‐Littrow,” however, was not a favorite of the operational mission planners. In spite of the pinpoint landing accuracy they had demonstrated on all previous missions since Apollo 11, the narrow valley, the mountainous approach, and the high valley walls gave the planners pause. Their legitimate concerns were compounded by the relatively short time, only 14 minutes, for navigational updates after acquisition of communications from the lunar module, Challenger, as its last orbit before landing carried it around the Moon from the farside. Initially, trajectory calculations indicated that three‐sigma errors, the normal extremely conservative planning limit, might result in hitting the side of the northern mountain wall. Gradually, however, refinements in navigational techniques for the mission and the inevitable synergistic give and take that so characterized Apollo interactions narrowed the three‐sigma errors to about 1 km, the limit where all agreed that Taurus‐Littrow could be the selected site. Thus, in late February 1972, only 9 months from launch, Taurus‐Littrow was approved as the exploration site for Apollo 17. The Valley of Taurus‐Littrow offered four major benefits as the last Apollo landing site, taken in the context of a final test of then current hypotheses related to the origin and evolution of the Moon. First, photogeologic analysis indicated that Taurus‐Littrow provided access to a three‐dimensional window into a mountain ring created by the Serenitatis large basin‐forming event, by now well established as the result of a giant impact of an asteroid or comet. Second, major units of mare basalt and older nonmare rocks would be within easy reach of roving vehicle traverses. Third, a mantle of dark, possibly young volcanic debris partially covered the region as well as portions of the valley, and craters of a range of depths penetrated this debris and the underlying basalt. And, fourth, the valley lies about 600 km north and 200 km east of the Apollo 11 and Apollo 15 sample areas, respectively, adding significantly to our exploration coverage of the Moon's nearside. Due to the foreknowledge that Apollo 17 would be the last of the Apollo series, selection of its landing site became a contentious issue among lunar scientists and between lunar scientists and operational planners. Impact cratering, origin and evolution of the Moon were subjects of Apollo 17's scientific informers and enquiries and are discussed.

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A new seismic velocity model for the Moon from a Monte Carlo inversion of the Apollo lunar seismic data

Cited by 137 publications

References 15 publications

Core Sizes and Internal Structure of Earth's and Jupiter's Satellites

Core Sizes and Internal Structure of Earth's and Jupiter's Satellites

Lunar bulk chemical composition: a post-Gravity Recovery and Interior Laboratory reassessment

Apollo 17 and the Moon

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