The purpose of this paper is to clarify the dynamic role lithospheric density heterogeneities, in particular with respect mountain building and other processes intraplate deformation. Density anomalies within or just beneath lithosphere constitute major sources for tectonic stress fields: product their magnitude by depth shown characterize ability induce This rule moment directly yields thickening thinning rate when applied structures large lateral extent. For extent that small comparison...

We address the question of how convective processes control thicknesses oceanic and continental lithospheres. The numerical convection model involves a Newtonian rheology which depends on temperature pressure. A repeated plate tectonic cycle is modeled by imposing time‐dependent surface velocity. One part surface, representing continent, never subducts. asymptotic equilibrium thickness lithosphere varies with viscosity at base lithosphere, but not directly sensitive to pressure dependence...

Narrow zones of intense shear deformation, i.e. viscous slip zones, are studied analytically with a one-dimensional time-dependent model two half-spaces identical or contrasting rheologies and ambient temperatures in relative motion. The the strongly temperature-dependent heating maintains thin zone high temperature, low viscosity large strain rate. mathematical is used to describe structures at ridge plate-boundary transform faults, major continental strike—slip faults top subducting...

Various types of observables (earthquake focal mechanisms, in situ measurements and geological deformations) give information about the large scale lithospheric stress field. The latter has often been explained by postulating appropriate forces acting at edges beneath plates. This approach ignores role mass heterogeneities within lithosphere. Here we analyze effect both boundary internal on pattern show that contributions are comparable magnitude. presence sources makes problem...

Megathrust earthquakes of magnitude close to 9 are followed by large-scale (thousands km) and long-lasting (decades), significant crustal mantle deformation. This deformation can be observed at the surface quantified with GPS measurements. Here we report on during 5 yr time span after 2010 Mw 8.8 Maule Earthquake (2010 February 27) over whole South American continent. With first 2 those data, use finite element modelling (FEM) relate this slip plate interface relaxation in mantle, using a...

Research Article| May 25, 2016 The Seismic Sequence of the 16 September 2015 Mw 8.3 Illapel, Chile, Earthquake Sergio Ruiz; Ruiz aDepartamento de Geofísica, Universidad Blanco Encalada 2002, Santiago, Chilesruiz@dgf.uchile.cl Search for other works by this author on: GSW Google Scholar Emilie Klein; Klein bLaboratoire Géologie, École Normale Supérieure, 24 Rue Lhomond, 75231 Paris, France Francisco del Campo; Campo cCentro Sismologico Nacional, Chile Efrain Rivera; Rivera dDepartamento...

Abstract We model surface displacements induced by variations in continental water, atmospheric pressure, and nontidal oceanic loading, derived from the Gravity Recovery Climate Experiment (GRACE) for spherical harmonic degrees two higher. As they are not observable GRACE, we use at first degree‐1 coefficients Swenson et al. (2008, https://doi.org/10.1029/2007JB005338 ). compare predicted with position time series of 689 globally distributed continuous Global Navigation Satellite System...

A numerical model of two‐dimensional Rayleigh‐Bénard convection is used to study the relationship between surface heat flow (or Nusselt number) and viscosity at base lithosphere. Newtonian or non‐Newtonian, temperature‐ pressure‐dependent rheologies are considered. In high Rayleigh number time‐dependent regime, calculations yield Nu ∝ Ra BL 1/3 b eff −4/3 where effective dependence with temperature upper thermal boundary layer calculated ν viscosity) layer. The same for non‐Newtonian if...

Abstract The occurrence of large earthquakes in stable continental interiors challenges the applicability classical steady state “seismic cycle” model to such regions. Here we shed new light onto this issue using as a case study cluster reverse faulting that occurred Fennoscandia at 11–9 ka, triggered by removal ice load during final phase regional deglaciation. We show these reverse‐faulting time when horizontal strain rate field was extensional, which implies events did not release...

We have investigated the impact of lateral viscosity variations (LVV) in top 300 km mantle on long-wavelength gravitational response Earth. In contrast to previous studies we demonstrate that LVV may play a crucial role if model with imposed plate velocities and partial layering is considered. Assuming associated continental roots oceanic asthenosphere, are able explain significant portion geoid (85 per cent) free-air gravity data (55 without invoking complex radial profile or assuming...

We have constructed a thermomechanical model for upper mantle convection such that the thickness and structure of lithosphere are determined self‐consistently by heat transported convection. In this study interaction between mantle, strongly temperature‐ pressure‐dependent rheologies both Newtonian non‐Newtonian creep mechanisms employed. For strictly temperature‐dependent rheology an insignificant amount heat, less than 12.5 mW/m 2 , can be convectively interior viscosity, 0(10 21 Pas),...

Topography associated with large wave‐length geoid is derived by two methods. First, the bathymetry corrected for sediment loading decomposed using a least‐squares method as function of age plus terms proportional to geoid. The topography at old ages flatter predicted law. At degrees 2 and 3, very little transfer not even certain in sign but never smaller than 0.6. More seems higher degree harmonics (6 7). Second, alone best fitting determined. correlation coefficients residual are then...

Fully two‐dimensional analytic boundary layer solutions are used to model the thermomechanical structure of oceanic upper mantle when a shallow horizontal return flow helps balance lithospheric transport mass from ridge trench. The following all incorporated in solutions: and vertical advection heat, heat conduction, viscous dissipation, adiabatic heating cooling, buoyancy, pressure‐ temperature‐dependent nonlinear rheology olivine. Depth profiles velocities, temperature, shear stress...

Geoid anomalies in the wavelength range corresponding to spherical harmonies 6 30 are used bring new constraints on deep structure of continental lithosphere, nature upper mantle seismic anomalies, and thermal evolution oceanic lithosphere. For shallow lithospheric density considered here, geoid anomaly is shown follow approximately moment law derived from isostasy. By a procedure least squares inversion, over old cratons found be equal that relatively young (50 Myr) The as function age...

The 2004 Aceh and 2005 Nias events are the two greatest earthquakes of past 40 years with a total rupture 1700 km long coseismic slip reaching up to 25 m. These have caused large stress perturbations which significantly altered seismic activity in Sumatra‐Andaman region. Using both detailed mapping failure planes various distributions, we calculate this change along Sumatra‐Andaman‐Sagaing fault system from central Sumatra southern Myanmar. static Coulomb Δ CFF observed very good agreement...

Glacial Isostatic Adjustment (GIA) models commonly assume a mantle with viscoelastic Maxwell rheology and fixed ice history model. Here, we use Bayesian Monte Carlo approach Markov chain formalism to invert the global GIA signal simultaneously for mechanical properties of volumes sheets, using as starting two previously published histories. Two stress relaxing rheologies are considered: Burgers linear viscoelasticities. A total 5720 palaeo sea level records used, covering last 35 kyr. Our...

Abstract Gravity Recovery And Climate Experiment and Follow On (GRACE/‐FO) global monthly measurements of Earth's gravity field have led to significant advances in quantifying mass transfer. However, a temporal gap between missions hinders evaluating long‐term variations. Moreover, instrumental processing errors translate into large non‐physical North‐South stripes polluting geophysical signals. We use Multichannel Singular Spectrum Analysis (M‐SSA) overcome both issues by exploiting...