using tidal potential, the effect of tide on the gravity field, crustal deformation due to tidal force, and gravity variations resulted from the crustal deformation are presented. tidal potential is divided into constant and periodic (diurnal and semi-diurnal) constituents, and for each constituents crustal displacements in radial, south-north, and east-west directions are computed. the aforeme...

[1] Admittance estimates from line-of-sight (LOS) acceleration profiles of the Mars Global Surveyor spacecraft are used to constrain the mean crustal thickness and surface density centered on the hemispheric dichotomy, from 110 E to 220 E, 40 S to 20 N. Models with uniform crustal properties predict lower than expected bulk crustal densities. Two-layer models with loading only at the surface an...

[1] Topographic profiles across a lobate fault scarp on Mercury have been used to constrain the depth of faulting to 30–40 km. Here we use this depth to place constraints on the crustal thickness and heat flow into the base of the crust. With no crustal heat production, the mantle heat flux on Mercury at the time of scarp formation was 30–50 mWm . However, higher crustal heat production rates a...

Crustal plateaus and volcanic rises, major physiographic features on Venus, both formed over mantle plumes. Crustal plateaus were produced by large degrees of plume melting beneath thin lithosphere. The oldest tectonic features in crustal plateaus are ribbon-like troughs indicating early uplift and tensile stretching; their shallow depths suggest that surface temperature there was higher in the...

H-κ stacking is a routinemethod for determining crustal thickness (H) and Vp/Vs (κ) using P-to-S (Ps) receiver functions. In this paper we show that S-to-P (Sp) receiver functions may also be used to determine crustal parameters. Sp provides independent information, complementary to Ps. We develop a method called H-V (crustal thickness-velocity) stacking where Ps and Sp receiver functions are s...

[1] The driving forces for crustal deformation are often inferred from the crustal kinematics. In the Southwestern United States, however, crustal kinematics delineated by the Global Positioning System (GPS) measurements differs significantly from that reconstructed from the geological records. This discrepancy is likely due to the different timescales reflected in these datasets. Here we explo...

Mantle convection patterns of the past are not well known, yet an understanding of changing mantle convection characteristics i fundamental to understanding the evolution of plate tectonics. There are very few ways to examine mantle characteristics of the past. Changes in spreading rate and volcanic activity with time have been used to draw conclusions about historic changes in mantle activity....

Small variations in gravity anomalies and topographic elevation observed in areas that have undergone highly variable amounts of upper crustal thinning can be satisfactorily explained by ductile flow of lower crustal material under the proper conditions. In this study we examine the boundary between the unextended Colorado Plateau and a strongly extended domain in the Basin and Range Province i...

The viscosity of lavas erupted at volcanic arcs varies over orders of magnitude. A comparison of the relative abundance of viscous lava dome eruptions indicates that the average viscosity of arc lavas also varies considerably between arcs. It is shown that for continental or transitional arcs with little within-arc crustal deformation and without underlying slab windows or tears, average lava v...

There is considerable controversy over the nature of geophysically recognized low-velocity-high-conductivity zones (LV-HCZs) within the Tibetan crust, and their role in models for the development of the Tibetan Plateau. Here we report petrological and geochemical data on magmas erupted 4.7-0.3 Myr ago in central and northern Tibet, demonstrating that they were generated by partial melting of cr...