Pablo M. Jacovkis

Evolution of the Upper Crustal Deformation in Subduction Zones

The uplift and evolution of a noncollisional orogen developed along a subduction zone, such as the Andean system, is a direct consequence of the interrelation between plate tectonic stresses and erosion. Tectonic stresses are related to the convergence velocity and thermal state, among other causes. In this paper, a new model designed to investigate the evolution of the topography and the upper crustal deformation of noncollisional orogens in a subduction zone produced by the oceanic crust being subducted is presented. The mechanical behavior of the crust was modeled by means of finite elements methods to solve Stokes equations for a strain-rate-dependent viscnplastic rheology. The model takes into account erosion effects using interface-trncking methods to assign fictitious properties to nonmaterial elements.

Statistical analysis of heterogeneities and their effect on build-up and drawdown tests

The objective of this work is to determine the effect of permeability and porosity spatial variations on well test pressure response. Data from three wells and synthetic data are used. Field data consist of permeability and porosity as functions of depth and pressure transient test measurements from the same wells. To achieve the objective, two different tools are applied: statistical characterization of heterogeneities and a well test interpretation method. For the data: (1) permeabilities are represented by exponential distribution functions; (2) constant porosity estimates that fit measured transient pressures are almost equal to the statistical arithmetic mean, while constant permeability estimates lie between the median and the arithmetic mean; and (3) minor permeability variations cause important changes in pressure response.

The First Decade of Computer Science in Argentina

Computer science has a curious history in Argentina: it began late (more than ten years later than in USA), had a ten-year span of flowering, was completely destroyed by the military dictatorship in 1966 and, disregarding some advances in small universities in the 1970s, began to weakly revive in 1983. In this article we shall analyze the ten-years long (1956–1966) “golden age” of computer science in Argentina, that is imbedded into a “golden age” of Argentinean universities.

Sensitivity analysis of shallow water problems via perturbative methods

We applied the perturbative theory to perform sensitivity analysis of the shallow water equations. The numerical solution of these equations was found via the mass lumping finite element technique. Then, the adjoint system of the shallow water equations was derived for the one-dimensional case and the expression of the sensitivity coefficient of a generic functional with respect to a generic parameter (Chezy resistance coefficient, solitary wave amplitude and bed channel slope) was obtained, using the differential formalism. The sensitivity of the mean functional, representing the first approximation of the velocity and the depth, was analyzed with regard to these parameters. Results of the sensitivity coefficients obtained via the perturbative methodology satisfactorily matched the values computed by the direct method, i.e., by means of the direct solution of the shallow water equations changing the values of input parameters for each case considered.

One-Dimensional Hydrodynamic Flow in Complex Networks: State of the Art, Some Applications and Generalizations

Climates differing from the present may result in other run-off systems, resulting in a change on any scale of river networks. While this is only of minor importance in the case of small creeks, large rivers adjusting to new equilibria may result in significant changes in erosion, sedimentation, and water discharge. Knowing more about such changes is therefore essential. Fluvial deltas and basins may be simulated by means of one-dimensional mathematical models that evolve in time and take into account the partial differential equations that govern the flow in each reach and the special equations needed at the junction points of the network. In this work, some theoretical and numerical analysis of this type of modeling is described, and some implications and generalizations are indicated.

Chaotic Toy Model of Mobile Beds in Natural Channels

The aim of this work is to formulate a dynamical model of mobile beds in natural channels. The proposed model is based on a simplified form of the rivers hydrodynamic equations and is similar to the generalized logistic map. As a natural consequence, the two parameters of the model are the control variables and they are related to properties of the real system. The qualitative regime of the phenomena has been totally reproduced by the proposed model.