Regional tectonism and volcanism affect crater modification and crater loss on Venus, but a comparison of Venusian craters to lunar floor-fractured craters uggests that a third style of more localized, crater-controlled magmatism also may occur on Venus. Based on lunar models for such magmatism, Venusian crustal conditions hould generally favor crater-filling volcanism over crater-centered floo...

Arecibo high-resolution (1.5 to 2 km) radar data of Venus for the area extending from Beta Regio to western Eisila Regio provide strong evidence that the mountains in Beta and Eisila Regiones and plains in and adjacent to Guinevere Planitia are of volcanic origin. Recognized styles of volcanism include large volcanic edifices on the Beta and Eisila rises related to regional structural trends, p...

This paper presents a general overview of ow in deformable porous media with emphasis on melt extraction processes beneath mid-ocean ridges. Using a series of simple model problems, we show that the equations governing magma migration have two fundamentally different modes of behaviour. Compressible two-phase ow governs the separation of melt from the solid and forms a non-linear wave equation ...

around the crater floor (Schultz 1976). Rarely, in cases of extreme crater modification (e.g., Gassendi), deformation Many floor-fractured craters on the Moon show surface deformation like that seen over terrestrial laccoliths. Consequently, can extend beyond the crater rim to form another annular terrestrial laccoliths provide one model for such crater modifitrough surrounding a narrowed, ridg...

Mount St Helens is the most active volcano within the Cascade arc; however, its location is unusual because it lies 50 km west of the main axis of arc volcanism. Subduction zone thermal models indicate that the down-going slab is decoupled from the overriding mantle wedge beneath the forearc, resulting in a cold mantle wedge that is unlikely to generate melt. Consequently, the forearc location ...

Long-standing debates exist over the timing and mechanism of uplift of the Tibetan Plateau and, more specifically, over the connection between lithospheric evolution and surface expressions of plateau uplift and volcanism. Here we show a T-shaped high wave speed structure in our new tomographic model beneath South-Central Tibet, interpreted as an upper-mantle remnant from earlier lithospheric f...

[1] Jupiter’s sodium nebula showed an enhancement in late May through the beginning of June 2007. This means Io’s volcanic activity and the magnetosphere’s plasma content increased during this period. On the other hand, Jupiter’s radio emission called HOM became quiet after the sodium nebula enhancement. The HOM emission is considered to be related to the activity of aurorae on Jupiter. These o...