Journal ArticleDOI
Structure of the Moon
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In this paper, the velocity structure of the moon's mantle has been analyzed by using natural impacts and deep moonquakes, and a simple model that can be proposed for the mantle consists of a "lithosphere" overlying an "asthenosphere".Abstract:
Seismic data fron the four stations of the Apollo passive seismic network have been analyzed to obtain the velocity structure of the moon. Analysis of body wave phases from artificial impacts of known impact time and position yields a crustal section. In the Mare Cognitum region the crust is about 60 km thick and is layered. In the 20-km-thick upper layer, velocity gradients are high and microcracks may play an important role. The 40-km-thick lower layer has a nearly constant 6.8-km/sec velocity. There may be a thin high-velocity layer present beneath the crust. The determination of seismic velocities in the lunar mantle is attempted by using natural impacts and deep moonquakes. The simplest model that can be proposed for the mantle consists of a 'lithosphere' overlying an 'asthenosphere'.read more
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A model for the hydrologic and climatic behavior of water on Mars
TL;DR: In this paper, an analysis of the hydrologic response of a water-rich Mars to climate change and to the physical and thermal evolution of its crust is carried out, with particular attention given to the potential role of the subsurface transport, assuming that the current models of insolation-driven change describe reasonably the atmospheric leg of the planet's long-term hydrological cycle.
Journal ArticleDOI
The Crust of the Moon as Seen by GRAIL
Mark A. Wieczorek,Gregory A. Neumann,Francis Nimmo,Walter S. Kiefer,G. Jeffrey Taylor,H. Jay Melosh,Roger J. Phillips,Sean C. Solomon,Sean C. Solomon,Jeffrey C. Andrews-Hanna,Sami W. Asmar,A. Konopliv,Frank G. Lemoine,David E. Smith,Michael M. Watkins,James G. Williams,Maria T. Zuber +16 more
TL;DR: In this article, high-resolution gravity data obtained from the dual Gravity Recovery and Interior Laboratory (GRAIL) spacecraft show that the bulk density of the Moon's highlands crust is 2550 kilograms per cubic meter, substantially lower than generally assumed.
Journal ArticleDOI
The Evolution of the Martian Hydrosphere: Implications for the Fate of a Primordial Ocean and the Current State of the Northern Plains
TL;DR: In this article, the authors consider the hydraulic and thermal conditions that gave rise to the elevated source regions of the Late Hesperian outflow channels and explore their implications for the evolution of the Martian hydrosphere.
Journal ArticleDOI
Attenuation of seismic waves in dry and saturated rocks: II. Mechanisms
TL;DR: In this article, several hypothesized attenuation mechanisms are discussed in relation to published data on the effects of pressure and fluid saturation on attenuation, including friction, fluid flow, viscous relaxation, and scattering.
Journal ArticleDOI
The Constitution and Structure of the Lunar Interior
Mark A. Wieczorek,Bradley L. Jolliff,Amir Khan,Matthew E. Pritchard,Benjamin P. Weiss,James G. Williams,Lon L. Hood,Kevin Righter,Clive R. Neal,Charles K. Shearer,I. Stewart McCallum,Stephanie Tompkins,B. Ray Hawke,C. A. Peterson,Jeffrey J. Gillis,Ben Bussey +15 more
TL;DR: The current state of understanding of the lunar interior is the sum of nearly four decades of work and a range of exploration programs spanning that same time period as discussed by the authors, which is the framework that unifies our knowledge of the structure and composition of the Moon.
References
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Book
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H. S. Carslaw,John Conrad Jaeger +1 more
TL;DR: In this paper, a classic account describes the known exact solutions of problems of heat flow, with detailed discussion of all the most important boundary value problems, including boundary value maximization.
Journal ArticleDOI
The velocity of compressional waves in rocks to 10 kilobars: 1.
TL;DR: The velocity of compressional waves has been determined by measurement of travel time of pulses in specimens of rock at pressures to 10 kilobars and room temperature as mentioned in this paper, mainly igneous and metamorphic rocks, furnished three specimens oriented at right angles to one another.
Journal ArticleDOI
Elastic moduli, pressure derivatives, and temperature derivatives of single‐crystal olivine and single‐crystal forsterite
Mineo Kumazawa,Orson L. Anderson +1 more
TL;DR: In this article, the adiabatic stiffness constants cij (in Mb), their temperature derivatives dcij/dT (10−4 Mb/deg), and their pressure derivatives dCij/dP, are measured as a function of pressure and of temperature near ambient conditions.
Journal ArticleDOI
The effect of saturation on velocity in low porosity rocks
Amos Nur,Gene Simmons +1 more
TL;DR: The shape of the pores in typical crystalline rocks plays an important role: increase in V p due to saturation of pores occurs when the pores are in the form of cracks but not when they are in a round hole as discussed by the authors.