A swarm of minette and melanephelinite dikes is exposed over 2500 km 2 in and near the Wasatch Plateau, central Utah, along the western margin of the Colorado Plateaus in the transition zone with the Basin and Range province. To date, 110 vertical dikes in 25 dike sets have been recognized. Strikes shift from about N80øW for 24 Ma dikes, to about N60øW for 18 Ma, to due north for 8-7 m.y. These...

[1] Phase equilibrium experiments on primitive Miocene olivine leucitite (Bb-107) from the Qiangtang terrane of the Tibetan Plateau were performed from 1.0 to 2.2 GPa and 1270 to 1440 C. The composition is multiply saturated with olivine and clinopyroxene from 1.2 to 2.2 GPa and 1340 C under nominally anhydrous conditions. Phase assemblages in the experiments have been used to model the effects...

The northeastern boundary of the Tibetan high plateau is marked by a 2 km topographic drop and a coincident rapid change in crustal thickness. Surface tectonics are dominated by the Kunlun strike-slip fault system and adjacent Kunlun concealed thrust. The main objective of the current study is to map lateral variations of seismic anisotropy parameters in this region along the linear INDEPTH IV ...

After the 1960 M9.5 Valdivia, Chile earthquake, three types of geodetic observations were made during four time periods at nearby locations. These post-seismic observations were previously explained by post-seismic afterslip on the down-dip extension of the 1960 rupture plane. In this study, we demonstrate that the post-seismic observations can be explained alternatively by volumetric viscoelas...

Multi-ring basins represent some of the largest, oldest, rarest and, therefore, least understood impact crater structures. Various theories have been put forward to explain their formation; there is currently, however, no consensus. Here, numerical modeling is used to investigate the onset of multi-ring basin formation on the Moon using two thermal profiles suitable for the lunar basin-forming ...

It is commonly thought hot diapiric flows prevail in the mantle wedge above the subducting slab. However, hydration and partial melting along the slab can create a situation in which a Rayleigh-Taylor instability can develop at the top of a cold subducting slab. We have modelled numerically with a high-resolution 2-D regional model this parodoxically interesting geological phenomenon in which r...

[1] The boundary of the Martian crustal dichotomy in the eastern hemisphere is one of the most striking topographic features on the planet. The long wavelength topography of much of the boundary is expressed by a broad rise and an arched ramp that slopes downward from the southern highlands into the northern lowlands and often ends in a steep scarp. Lithospheric flexure of the southern highland...

The process of stress accumulation near earthquake faults during the aseismic period in between two major seismic events in seismically active regions has become a subject of research during the last few decades. Earthquake fault of finite length of strike-slip nature in a viscoelastic layer over a viscoelastic half space representing the lithosphere-asthenosphere system has been considered her...

[1] Mantle dynamics can strongly affect melting processes beneath spreading centers and volcanic arcs. A 2-D numerical model of the Tonga subduction zone, with the slab viscously coupled to the mantle beneath the brittleductile transition but faulted above, shows that induced corner flow may cause asymmetric melting at the Lau backarc spreading center, 400 km away. The down-going slab also entr...

The analysis of GRACE gravity data revealed postseismic gravity increase by 6 μGal over a 500 km scale within a couple of years after the 2011 Tohoku-Oki earthquake, which is nearly 40-50% of the coseismic gravity change. It originates mostly from changes in the isotropic component corresponding to the Mrr moment tensor element. The exponential decay with rapid change in a year and gradual chan...