Diciembre 2007
Percolation conditions in fractured hard rocks: A numerical approach using the three-dimensional binary fractal fracture network (3D-BFFN) model
Authors: Shinji Nakaya, Kiminori Nakamura et al
Link: Click Aquí

Abstract
We numerically investigate fracture connectivity and percolation conditions in fractured hard rocks using a three-dimensional binary fractal fracture network (3D-BFFN) model based on three fractal geometric parameters: the fractal dimensions (D2) of the spatial distribution of fractures, the exponent of the power-law cumulative fracture length distribution (a), and the maximum fracture length (l max) normalized by the domain length (L), l max/L. Numerical results clarify that the percolation threshold in 3D-BFFN models is strongly controlled by fractal geometric parameters and is independent of any anisotropy in the orientations T. In addition, when a < 1.8 and

Abstract
In our study we show that the locations of largest coseismic slip (asperities) on the fault plane of the M w = 8.0 1995 Antofagasta earthquake in Northern Chile can be mapped by the spatial distribution of the seismic b value obtained from the aftershock sequence of the megathrust earthquake. These areas of high seismic moment release and concurrent high-b values are congruent with anomalies of the gravity isostatic residual (IR) field in the Antofagasta region. They are superimposed on the seismogenic part of the north Chilean subduction zone where the

Abstract
Seafloor fault scarps and near-surface deformation of late Quaternary seismic reflectors occur along the eastern margin of the Wanganui Basin, 200 km behind the active Hikurangi subduction front, southern North Island, New Zealand. The offshore scarps are associated with the low-strain, compressional Kapiti-Manawatu Fault System (KMFS), which comprises high-angle (>60°) reactivated reverse and normal faults oriented NE-SW, highly oblique to the coast. Seafloor scarps range from <10 to 50 km in length with vertical seafloor offsets of 2 to 30 m. The longest structure is the Mascarin Fault, with

Abstract
Box counting is widely used for characterizing fracture networks as fractals and estimating their fractal dimensions (D). If this analysis yields a power law distribution given by N r -D , where N is the number of boxes containing one or more fractures and r is the box size, then the network is considered to be fractal. However, researchers are divided in their opinion about which is the best box-counting algorithm to use, or whether fracture networks are indeed fractals. A synthetic fractal fracture network with a known D value was used to develop a new algorithm for the box-counting method that returns improved estimates of D. The method is based on identifying the lower limit of fractal behavior (r cutoff) using the condition ds/dr ? 0, where s is the standard deviation from a linear regression equation fitted to log(N) versus log(r) with data for r < r cutoff sequentially excluded. A set of 7 nested fracture maps from the Hornelen Basin, Norway was used to test the improved method and demonstrate its accuracy for natural patterns. We also reanalyzed a suite of 17 fracture trace maps that had previously been evaluated for their fractal nature. The improved estimates of D for these maps ranged from 1.56 ± 0.02 to 1.79 ± 0.02, and were much greater than the original estimates. These higher D values imply a greater degree of fracture connectivity and thus increased propensity for fracture flow and the transport of miscible or immiscible chemicals.

Abstract
We investigate the rupture process of a sequence of repeating Mw 2.1 earthquakes on the San Andreas Fault in Parkfield spanning the occurrence of the September 28, 2004 mainshock by inverting seismic moment rate functions obtained from empirical Green's function deconvolution. The results show that these events have extremely concentrated slip patches with radii on the order of 10-20 m, with peak slip between 8.4 and 11.4 cm. The rupture speed and rise time are consistent with values of larger earthquakes. The spatial distribution of stress drop for the events shows low average values 2.5-5.6 MPa and very large peak values of 66.7-93.9 MPa. The results show that strong asperities can exist at small scales on an otherwise weak fault, and helps reconcile differences between traditional spectra-based and tectonic loading methods for determining the stress drop of small repeating earthquakes.

Abstract
A seismic experiment composed of streamer and ocean bottom seismometer (OBS) surveys was conducted in the summer of 2002 at southern Hydrate Ridge, offshore Oregon, to map the gas hydrate distribution within the hydrate stability zone. Gas hydrate concentrations within the reservoir can be estimated with P wave velocity (V p ); however, we can further constrain gas hydrate concentrations using S wave velocity (V s ), and use V s through its relationship to V p (V p /V s ) to reveal additional details such as gas hydrate form within the matrix (i.e., hydrate cements the grains, becomes part of the matrix frame or floats in pore

Abstract
The spatial pattern of the b value of the frequency-magnitude relation has been analyzed using gridding techniques beneath Mount Etna, Italy. A regional data set of 2900 events with M d (duration magnitude) =1.5 up to 15 km depth occurring between August 1999 and December 2005 has been used. Two regions with an abnormally high b value have been found, one centered beneath the southern part of the Valle del Bove, above the 6 km below sea level (bsl) deep basement, and the other beneath the summit region 2 km bsl

Abstract
The northern Longitudinal Valley fault in eastern Taiwan creeps at the surface with a small rate of ~1 cm/yr but slips in large earthquakes. To

Diciembre 2007

Interacciones entre terremotos
y actividad volcánica

Autores: Nicolas Lemarchand y Jean-Robert Grasso
Link: Click Aquí

Abstract
Utilizando el catálogo mundial 1973-2005 para sismicidad M >= 4.8 y erupciones volcánicas con VEI >= 0, encontramos un incremento del inicio de la actividad volcánica el día del terremoto. Este resultado emerge del estudio de las series de tiempo de razones diarias de erupción relativas al tiempo to del terremoto, respecto de la sismicidad global incluída en el catálogo. La correlación es fuerte para los pares terremoto-actividad volcánica (TV), siempre que el volcán se ubique dentro de una distancia al epicentro menor o igual a diez veces la longitud de ruptura. Los resultados muestran que para M >= 4.8 y VEI >= 0, los pares TV son tan importantes como los procesos de interacción con M >= 7 and VEI >= 2-5 previamente reportados. La agrupación temporal para los pares TV no está necesaria-mente referida a to. La correlación se distribuye en torno de to con una dispersión de 6 a 10 días (antes y después del terremoto) y sigue una ley de potencias . Estos patrones, los cuales son similares a las leyes directas e inversas de Omori observadas para terremotos tectónicos, corresponden a la primera evidencia que muestra que las erupciones volcánicas son contempo-ráneas al rompimiento de la corteza terrestre.
Las agrupaciones espaciotemporales que observamos nos permiten concluir lo siguiente:
i) Es incorrecto que el disparo del terremoto es el único proceso que influye en el par TV
ii) Se aportan pruebas que nos indican un acoplamiento regional tectónico en el daño de la corteza terrestre.

Abstract
A model is proposed to explain the spatial distribution of foreshocks of the June 17th 2000, M s 6.6 earthquake in the South Iceland Seismic Zone (SISZ) and the high stress drop of the

Abstract
One of the major objectives of the future Martian surface probes will be to reveal a past or present biological activity. We propose that biominerals could have recorded such an activity at Mars, and thus could be interesting targets for these missions. Therefore, we try to find a method

Abstract
Laboratory experiments show that the rate of decrease in gas phase permeability as a function of water saturation can be large at small saturations. Drying out the water saturation during gas injection has been observed to reduce absolute permeability. This paper proposes a quantitative grain-scale explanation for these observations. We also show why the effect is

Abstract
We report the magnetic properties of pure synthetic pseudo-single-domain (PSD) and multi-domain (MD) greigite and the grain size dependence of the magnetic properties of greigite for the first time. The dominantly PSD-like and MD-like behavior are demonstrated by hysteresis, first-order reversal curve diagrams, low -

Abstract
Este paper resume un marco conceptual para la investigación de la predictibilidad a partir de la Teoría de la Información. Este marco conecta y unifica una gran variedad de métodos estadísticos utilizados tradicionalmente en análisis de predictibilidad, incluyendo regresión lineal, análisis de correlación canónica, descomposición de valores singulares, análisis de discriminante y asimilación de datos. La base de este marco es un procedimiento llamado Análisis de Componentes Predecibles (PrCA). El PrCA realiza una descomposión óptima de las variables que se pueden utilizar para realizar predicitibilidad, así como el Análisis de Componentes Principales descompone óptimamente las variables a partir de su varianza. Para distribuciones normales se obtiene los mismos componentes predecibles, ya sea que se optimice la información predecible, la dispersión de la entropía relativa, la información mutua, el error de Mahalanobis, la razón entre la señal promedio y el ruido, el error cuadrático medio normalizado o la anomalía de correlación. Para distribuciones normales conectadas, el PrCA es equivalente al análisis de correlación canónico entre pronóstico y observaciones. El operador de regresión que mapea de observaciones a pronósticos juega un importante rol en este marco, dejando los vectores singulares del operador como los componentes predecibles, al tiempo que los valores singulares son las correlaciones canónicas. Esta última correspondencia ocurre sólo si los vectores singulares son calculados mediante la norma de Mahalanobis, un resultado que aclara el rol de la norma en la predictibilidad. En modelos estocásticos lineales el hecho que impone la minimización de la predicitibilidad es lo único que define la dinámica "blanca" del operador normal. Esta condición para predictibilidad mínima es invariante frente a las transformaciones lineales y es equivalente a un balance detallado. El marco también inspira algunos nuevos acercamientos para contabilizar las deficiencias de los modelos de pronóstico y estimar distribuciones a partir de un muestreo finito.

Abstract
Insight into the size and morphology of assemblages of magnetite particles can be gained by comparing temperature variations of remanence or susceptibility after zero-field cooling (ZFC) and after field cooling (FC) through the Verwey transition around T v = 120 K. At 10 K a sample is demagnetized following ZFC, but in the FC initial state before warming the sample has a transition cooling remanence (TrCRM) acquired in crossing T v. The matching transition warming remanence (TrWRM) acquired as a result of heating a demagnetized sample from low temperature across T v is often called inverse thermoremanent magnetization (ITRM). In TrCRM experiments, initially demagnetized samples were cooled in a 2 mT field from 300 K to 10 K. Magnetization M was measured at 1 K to 5 K

Abstract
Previous workers identified a magnetically anomalous clay layer deposited on the northern United States Atlantic Coastal Plain during the Paleocene-Eocene thermal maximum (PETM). The finding inspired the highly controversial hypothesis that a cometary impact triggered the PETM. Here we present ferromagnetic resonance (FMR), isothermal and anhysteretic remanent magnetization, first-order reversal curve, and

Abstract
We present a new crustal seismic velocity model for southern California derived from P and S arrival times from local earthquakes and explosions. To reduce the volume of data and ensure a more uniform source distribution, we compute "composite event" picks for 2597 distributed master events that include pick information for other events within spheres of 2 km radius. The approach reduces random picking error and maximizes the number of S wave picks. To constrain absolute event locations and shallow

Abstract
Volcanic and plutonic rocks provide abundant evidence for complex processes that occur in magma storage and transport systems. The fingerprint of these processes, which include fractional crystallization, assimilation, and magma recharge, is captured in petrologic and geochemical characteristics of suites of cogenetic rocks. Quantitatively evaluating the relative contributions of each process requires integration of mass, species, and energy constraints, applied in a self-consistent way. The energy-constrained model Energy-Constrained Recharge, Assimilation, and Fractional Crystallization (EC-Ra FC) tracks the trace element and isotopic evolution of a magmatic system (melt + solids) undergoing simultaneous fractional crystallization,

Abstract
Isotopic fractionation of carbon and hydrogen in methane and ethane during the formation of gas hydrates was investigated. The gas hydrate samples were experimentally prepared in a

Abstract
The presence of the global magnetic field of Mercury has implications for the interior structure of the planet and its thermal evolution. We use a thermal evolution model to explore the conditions under which excess entropy is available to drive a convective dynamo. The current state of the core is

Abstract
When choosing the rainfall-runoff modeling approach to be integrated in a river flow forecasting system, two crucial issues are the minimum data requirement for calibration purposes and the reliability of the predictions over different time horizons (lead-times). The paper presents an investigation of the real-time

Abstract
A novel data-driven artificial neural network (ANN) that quantitatively combines large numbers of multiple types of soft data is presented for performing stochastic simulation and/or spatial estimation. A counterpropagation ANN is extended with a radial basis function to estimate parameter fields that reproduce the spatial structure exhibited in autocorrelated parameters. Applications involve using three geophysical properties measured on a slab of Berea sandstone and the delineation of landfill leachate

Abstract
Seismograms from a dense, high-quality seismic network in Japan are used to investigate the characteristics of the 26 December 2004 Sumatra-Andaman and the 28 March 2005 Sumatran earthquakes. The onset of the P waveforms are aligned through cross correlation, and a simple concept of back-projecting seismic energy to a grid of potential source locations is applied. The waveform alignment removes the effects due to lateral variations in wave speed between the hypocenter and each station. To better approximate the effects of three- dimensional heterogeneity for paths originating from grid points away from the hypocenter, cross-

Abstract
Two tsunami earthquakes occurred in the Java subduction zone within the last 12 years, providing multiple well-recorded tsunami events for analysis. The June 2, 1994 Mw = 7.8 and July 17, 2006 Mw = 7.7 reverse mechanism earthquakes produced tsunami with locally large (>8 m)

Abstract
High time resolution monitoring of radon (=222Rn) in three boreholes, 4, 10 and 53 m deep, along a 0.6 km transect is carried out in massive granite in southern Israel. Three components of variation occur in the measured signal (MS) - seasonal radon (SR - periodic), multiday (MD), and daily radon (DR - periodic). Temporal variation of the components suggests an association between the overall level of the long-term variation and the amplitude of the daily variation. The daily mean level of radon and the daily standard deviation vary periodically throughout the year. Time offsets occur among

Abstract
The multi-dimensional transition probability model represents hydrofacies architecture in modeling aquifer heterogeneity. The structure of the aquifer architecture is mathematically characterized by a canonical representation of the transition probability matrix, solved by an eigenvalue decomposition method. Whereas the eigenvalue decomposition has been numerically solved previously, we show here that it can be analytically solved under the assumptions that

Abstract
Biogenic free-phase gas (FPG) formation was induced in a peat block (dimensions 0.28 × 0.21 × 0.21 m) extracted from a peatland in Maine. Electrical resistivity (ER), surface deformation, and methane (CH4) flux from the peat surface was monitored over a 48-day period during which the temperature remained constant at 21 ± 1°C. ER measurements were made on 5 vertical electrode arrays, each containing 20 electrodes spaced at 0.01-m intervals. Surface deformation was monitored using 30 elevation rods equally spaced across the surface of the block, and average CH4 flux from the peat surface estimated by integration of measurements obtained with a portable gas detector over a 20-min time period. Pore water conductivity was recorded at three depths (0.06, 0.09, and 0.15 m) at a single point in the block. ER measurements were inverted for the ratio resistivity change relative to a background data set and corrected for changes in pore fluid conductivity, permitting an estimate of equivalent change in gas content assuming (1) insignificant surface conduction, (2) porosity changes estimated from peat surface expansion, and (3)

Abstract
Pore magnetic anisotropy can be used to estimate the average geometry of void spaces in rocks in the form of the equivalent pore (EP) ellipsoid. Direct computation of EP from

Abstract
Ruddiman (2003) proposed that late Holocene anthropogenic intervention caused CH4 and CO2 increases that kept climate from cooling and that preindustrial pandemics caused CO2 decreases and a small cooling. Every aspect of this early anthropogenic hypothesis has been challenged: the timescale, the issue of stage 11 as a better analog, the ability of human activities to account

Abstract
We investigate the climate forcing from and response to projected changes in short-lived species and methane under an A1B scenario from 2000-2050 in the GISS climate model. We present a meta-analysis of new simulations of the full evolution of gas and aerosol species and other existing experiments with variations of the same model. The comparison highlights the importance of several physical processes in determining radiative forcing, especially the effect of climate change on stratosphere-troposphere exchange, heterogeneous sulfate-nitrate-dust chemistry, and changes in methane oxidation and

Abstract
The possibility that the frequency content of ground motion in earthquakes affects hydrological responses to earthquakes has yet to be extensively tested in the field. The M w = 7.6 Chi-Chi earthquake provided an opportunity to do so, as widespread liquefaction and groundwater level changes were recorded by instrumentation in the

Abstract
La deformación temporal observada en los ciclos de terremotos y la permanente tensión asociada a la convergencia de placas, nos puede propor-cionar pistas críticas para entender la geodiná-
mica y el riesgo de terremotos en las zonas de subducción. En el sector de Valdivia que se vio afectado por el terremoto Mw 9.5 en el año 1960, nosotros hemos obtenido información de ambos tipos a partir de lecturas de GPS. Nuestras esti-
maciones de velocidad coinciden con el rango latitudinal completo, considerando las primeras llegadas. Las nuevas observaciones revelaron un patrón de oposición del movimiento entre la costa y los sitios interiores, consistente con las observaciones septentrionales reportadas previamente. Los datos apoyan el modelo de prolongada deformación postsísmica como resultado de relajación tensional viscoelástica del manto. Nuestras observaciones también propor-
cionan la primera evidencia geodésica sobre el movimiento diestro del sistema de fallas intra-
volcánico y la consecuente traslación del frente de la curvatura. El movimiento puede ser modelado con una rapidez de 6.5 mm/a, incluyendo el 75% del margen paralelo de las placas de Nazca y Sudamericana, movimiento que disminuye hacia el norte. Además, las observaciones de GPS indican una disminución meridional en las velocidades del margen normal del área costera. Preferimos explicar el fenómeno en términos de cambios de las propiedades de la superficie de fricción. Debido a la juventud de la placa subducting y al régimen termal templado en el sur, el actual sector bloqueado de la placa puede ser más estrecho. Utilizando un modelo visco-
elástico 3D basado en elementos finitos, noso-
tros demostramos que nuestra explicación es consistente con las observaciones a primer orden (aunque no es la única explic. posible).

Abstract
We study the deformation and morphology of the magnetic field near Titan by a three-dimensional numerical quasi-neutral hybrid model (HYB-Titan). We analyze two runs, one in which the sub-rotating plasma consists of oxygen (O+) ions and protons (H+) and another with only protons. We

Abstract
Based on the hierarchical self-similar geometry of fault zones in which fault segments and jogs of different hierarchical ranks are nested, I

Abstract
Differential traveltimes of SS precursors have been widely used to map large-scale mantle structure and depths of discontinuities. Measurements are commonly made by stacking individual records to increase the signal-to-noise ratio pertaining to these mild reflections. However, ray parameters of the SS precursors are typically less well constrained and undesired seismic arrivals with vastly different slownesses (for example, scattered waves) could potentially contaminate the time domain stacks. To overcome these pitfalls, we introduce a processing scheme based on the Radon transform and well-constrained inversions. Our

Abstract
Reconnection occurs in a reconnection magnetic field geometry when there are positive electric field components tangential to the magnetopause and a magnetic field component normal to it. Because these three components are the smallest of the six electric and magnetic fields, their magnitudes are difficult to determine because of errors in, or oscillations of, the assumed constant direction normal to the current sheet. A method is described for minimizing these

Abstract
Titan's induced magnetotail is analyzed in terms of a three-dimensional hybrid model, treating the electrons as a massless, charge-neutralizing fluid, whereas a completely kinetic approach is used to cover ion dynamics. Since during the T9 flyby of Cassini, the spacecraft passed through

Abstract
Two years after the Great Sumatra-Andaman earthquake the 3.1 m WSW coseismic displacement at Port Blair, Andaman Islands, had increased by 32 cm. Postseismic uplift initially exceeded 1 cm per week and decreased to <1 mm/week. By 2007 points near Port Blair had

Abstract
Different from the conventional approach to tsunami warnings that rely on earthquake magnitude estimates, we have found that coastal GPS stations are able to detect continental slope displacements of faulting due to big earthquakes, and that the detected seafloor displacements are able to determine tsunami source energy and

Abstract
Scoria cones have been regarded to be formed by accumulation of ballistic bombs ejected by mild eruptions. However, more recent geological investigations show that some scoria cones could be formed during explosive eruptions. Here, we demonstrate how the scoria cone of the 1986 Izu-Oshima eruption was formed during the explosive

Abstract
We estimated the regional stress field before and after the 2000 Western Tottori Earthquake (Mw = 6.6) from numerous focal mechanisms. To constrain the stress field prior to the main shock, we compared the spatial distribution of the static stress changes generated by the main shock with the stress field following the main shock. In the northern and central parts of the aftershock region, it is inferred that the deviatoric stress magnitude prior to the main shock was too large to be affected by the static stress changes. The

Abstract
ULF waves generated by the release of a neutral gas in the equatorial plane of the Earth's magnetosphere will be trapped between two turning points forming a resonator. This effectively prolongs the lifetime of the ensuing turbulence making it more useful for pitch angle scattering

Abstract
This study proposes an approach, SATS-GWT, that combines simulated annealing (SA), tabu search (TS), and the three-dimensional groundwater flow and solute transport model (MODFLOW-GWT). Our approach is used to estimate the source information: source location, release concentration, and release period. The sampling concentrations at monitoring points are simulated by the MODFLOW-GWT with an assumed release concentration and release period at a known source location. In the source estimation process, the source location is

Abstract
This paper summarizes the histories of geomagnetism and paleomagnetism (1269–1950). The role of Peregrinus is emphasized. In the sixteenth century a debate on local versus global departures of the field from that of an axial dipole pitted Gilbert against Le

Abstract
We assessed the accuracy of earthquake source parameters inverted from simulated Interferometric Synthetic Aperture Radar (InSAR) data. Using focal mechanisms of Australian earthquakes (1959 to the present), we simulated synthetic two-pass InSAR observations with realistic spatial noise derived from the characteristics of actual ERS-2 and ENVISAT InSAR data observed over Australia. The precision of two-pass satellite SAR interferometry with ERS-2 and ENVISAT SAR data in the Australian region can approach ±2 mm (1σ) and is routinely at the ±4 mm level. The use of spatially correlated

Abstract
A group of geophysical applications, which from the mathematical point of view, can be formulated as complex, multidimensional, nonlinear mappings and which in terms of the neural network (NN) technique, utilize a particular type of

Abstract
The northern escarpments of the Hess Deep Rift provide cross-sectional views of in situ, aprox 1-Ma-old, upper oceanic crust that underwent extensive, spreading-related brittle deformation. Most of the deformation and associated alteration occurred within the locus of magmatic construction of the East Pacific Rise, in the presence of high-temperature hydrothermal fluids. Passing laterally from undeformed host rocks, brittle deformation zones are classified as (1) damage zones where densely spaced fractures overprint the primary structure of dikes and lavas, (2) cataclastic zones where interconnected fractures, comminuted grains, and matrix minerals define deformational fabrics, and (3) very fine-grained, gouge-filled fault cores. Relative to

Abstract
This work aims to provide insights into the initiation and evolution of segments along ocean ridges as they propagate and mature. It is based on the results of analogue modeling performed in a centrifuge with applied acceleration of gravity force. The effect of the varied degree of extension

Abstract
Quaternary lavas erupted in zones of tectonomagmatic extension within the Main Ethiopian Rift (MER) preserve details of lithospheric structure in the East African Rift System. Despite observed source heterogeneity, basalts, trachybasalts, and basaltic trachyandesites erupted in the Wonjii Fault Belt (WFB) and the Silti-Debre Zeyit Fault Zone (SDFZ) form coherent fractionation paths dominated by variable removal of observed phenocryst phases. Crustal assimilation is not widespread, though it is observed at the southern end of the WFB where both fault belts merge; farther north, assimilation of cumulate phases related to fractional crystallization of previous magmas is identified. Shallow fractionation conditions (1 kbar) within

Abstract
Models are great tools to test ideas. Their usefulness, however, depends on their ability to simulate the current reality and to predict the future. In this study, I have derived a new t* distribution. I show that a statistical model based on the t* distribution of station temporal data

Abstract
Measurements of 220Rn and 222Rn activity and of CO2 flux in soil and fumaroles were carried out on Mount Etna volcano in 2005–2006, both in its summit area and along active faults on its flanks.

Abstract
One of the principal sources of uncertainty in hydrological models is the absence of understanding of the complex physical processes of the hydrological cycle within the system. This leads to uncertainty in input selection and consequently its associated parameters, and hence evaluation of uncertainty in a model becomes important. While there has been considerable interest in developing methods for uncertainty analysis of artificial neural network (ANN) models, most of the methods are relatively complex and/or require assumption about the prior distribution of the uncertain parameters. This paper presents an effective and simple way to

Abstract
The early stages of the 2002-2003 lateral eruption at Mount Etna were accompanied by slow changes (over some hours) and some rapid step offsets in the local magnetic field. At five monitoring locations, the total magnetic field intensity has been measured using continuously operating Overhauser seismic events located roughly midway between the magnetic stations. We quantitatively examine possible geophysical mechanisms, which could cause the magnetic anomalies. The comparison between magnetic data, seismicity and surface phenomena implies that piezomagnetic effects are the primary

Septiembre 2007
Presentan EIA para explotación del Tatio como alternativa energética
(Boletín ACHS)
Link: Click Here

II Región.- Se presentó oficialmente el Estudio de Impacto Ambiental (EIA) del proyecto "Perforación Geotérmica Profunda El Tatio Fase Uno", a cargo

Abstract
We develop a new hierarchical earthquake rupture model that takes into account mesoscopic-scale fault structure; shear branches nucleated on the main fault are specifically assumed as an example of mesoscopic-scale fault structure. We numerically investigate dynamic formation of fault geometry and its effects on dynamic earthquake rupture process based on this rupture model. As long as the length of the main fault is below a certain threshold L m, the growth of these branches is shown to be arrested spontaneously soon after their nucleation. The spatial distribution of arrested branches is shown to form a self-

Abstract
A new planetary atmospheric numerical model, "planetWRF," has been developed by modifying the Weather Research and Forecasting (WRF) model. The model has generalized map projection, multiscale, and nesting capabilities, blurring the distinction between global and mesoscale models and enabling investigation of

Abstract
The Earth's shallow subsurface results from integrated biological, geochemical, and physical processes. Methods are sought to remotely assess these interactive processes, especially those catalysed by micro-organisms. Using saturated sand columns and the metal reducing bacterium Shewanella oneidensis MR-1, we show that electrically conductive appendages

Abstract
We have performed a series of experiments to investigate the compositional effect on the compression behavior of (Mg, Fe)O solid solutions at high pressure. The in-situ synchrotron X-ray diffraction data revealed abnormal volume contractions at about 40, 60 and 80 GPa for (Mg0.80, Fe0.20)O, (Mg0.61, Fe0.39)O,

Abstract
Three-dimensional advective transport of passive solutes through isotropic porous formations of stationary non-Gaussian log conductivity distributions is investigated by using an approximate semianalytical model, which is compared with accurate numerical simulations. The study is a continuation of our previous works in which formation heterogeneity is modeled using spherical nonoverlapping inclusions and an approximate analytical model was developed. Flow is solved for average uniform velocity, and transport of an ergodic plume is quantified by mass flux (traveltime distribution) at a control plane. The analytical model uses a self-consistent transport of an ergodic plume is quantified by mass flux (traveltime distribution) at

Abstract
This paper proposes a neural network (NN)-embedded genetic algorithm (GA) approach for solving inverse water quality modeling problems to overcome the computational bottleneck of inverse modeling by replacing a water quality

Abstract
Several models have been proposed to relate slab geometry to parameters such as plate velocity or plate age. However, studies on the observed relationships between slab geometry and a wide range of subduction parameters show that there is not a simple global relationship between slab geometry and any one of these other subduction parameters for all subduction zones. Numerical and laboratory models of subduction provide a method to explore the relative importance of different physical processes in determining subduction dynamics. Employing 2-D numerical models with a viscosity structure

Abstract
Volcanic tremor signals recorded by an infrasound array ~12.5 km from the active vent of Kilauea Volcano show clear diurnal amplitude variations and originate from a well defined direction pointing to the active Pu`u `O`o crater complex. Spectral amplitudes between 0.02-0.3 Hz, a proxy for wind speed, increase when the wind speeds increase during the daytime.