north-east khorasan is one of the most active regions in the world because of is setting on the alpine-himalayan belt. historical and geological backgrounds suggest that this region has experienced many destructive earthquakes throughout history. compared with the historical background, the seismicity of the region, in the present century, is better known both from the macroseismic and instrume...

The number of broa.dband three-component seismic stations in southern California. has more tb an tripled recently. In th is study we use the teleseismic receiver function technique to determine the crustal thicknesses and Vp / Vs ratios for th ese stations and map out t he lateral variation of Moho dept h under southern California. It is shown t hat a. receiver function can provide a very good ...

We derive expressions for computing the gravitational field (potential and its radial derivative) generated by an arbitrary homogeneous or laterally varying density contrast layer with a variable depth and thickness based on methods for a spherical harmonic analysis and synthesis of gravity field. The newly derived expressions are utilised in the gravimetric forward modelling of major known den...

Introduction: The two most striking surface features on Mars are the crustal dichotomy and the Tharsis Rise [1]. While it is generally accepted that the Tharsis Rise is formed as a result of plume related volcanism [2], the formation mechanism for the crustal dichotomy is controversial with two main competing proposals: endogenic (mantle convection and flow) [3-5] and exo-genic (mega-impact) me...

Crustal plateaus on Venus constitute one of that planet’s most intriguing tectonic features. They host so-called “tessera” terrain, or deformed crust exhibiting two or more sets of intersecting tectonic lineaments, which comprises ∼8% of Venus’ surface. Major questions surrounding crustal plateaus and tessera terrain include: (1) What is the nature of crustal plateau deformation? What structure...

Spreading segments of the Mid-Atlantic Ridge show negative bull's-eye anomalies in the mantle Bouguer gravity field. Seismic refraction results from 33 degrees S indicate that these anomalies can be accounted for by variations in crustal thickness along a segment. The crust is thicker in the center and thinner at the end of the spreading segment, and these changes are attributable to variations...