Structure and recent evolution of the Hazar Basin: a strike‐slip basin on the East Anatolian Fault,Eastern Turkey     

D. Garcia Moreno  A. Hubert‐Ferrari  J. Moernaut  J. G. Fraser  X. Boes  M. Van Daele  U. Avsar  N. Çağatay  M. De Batist 《Basin Research》2011,23(2):191-207

The Hazar Basin is a 25 km‐long, 7 km‐wide and 216 m‐deep depression located on the central section of the East Anatolian Fault zone (eastern Turkey) and predominantly overlain by Lake Hazar. This basin has been described previously as a pull‐apart basin because of its rhombic shape and an apparent fault step‐over between the main fault traces situated at the southwestern and northeastern ends of the lake. However, detailed structural investigation beneath Lake Hazar has not been undertaken previously to verify this interpretation. Geophysical and sedimentological data from Lake Hazar were collected during field campaigns in 2006 and 2007. The analysis of this data reveals that the main strand of the East Anatolian Fault (the Master Fault) is continuous across the Hazar Basin, connecting the two segments previously assumed to be the sidewall faults of a pull‐apart structure. In the northeastern part of the lake, an asymmetrical subsiding sub‐basin, bounded by two major faults, is cross‐cut by the Master Fault, which forms a releasing bend within the lake. Comparison of the structure revealed by this study with analogue models produced for transtensional step‐overs suggests that the Hazar Basin structure represents a highly evolved pull‐apart basin, to the extent that the previous asperity has been bypassed by a linking fault. The absence of a step‐over structure at the Hazar Basin means that no significant segmentation boundary is recognised on the East Anatolian Fault between Palu and Sincik. Therefore, this fault segment is capable of causing larger earthquakes than recognised previously.  相似文献   

The United Nations system responds to Agenda 21.17: Oceans     

Heiner Naeve  Serge M. Garcia 《Ocean & Coastal Management》1995,29(1-3)

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On spin-driven inflation from inflation fields in General Relativity and COBE data     

L. C. Garcia de Andrade 《Astrophysics and Space Science》2004,294(3-4):213-217

Obukhov spin-driven inflation in general relativity is extended to include inflation fields. A de Sitter phase solution is obtained and new slow-rolling conditions for the spin potential are obtained. The spin potential reduces to Obukhov result at the present epoch of the Universe where the spin density is low with comparison to the Early Universe spin densities. A relation between the spin density energy and the temperature fluctuation can be obtained which allow us to determine the spin density energy in terms of the COBE data for temperature fluctuations.  相似文献   

The solar flares of February 1986 and the ensuing intense geomagnetic storm     

Howard A. Garcia  Murray Dryer 《Solar physics》1987,109(1):119-137

A very intense geomagnetic storm, the largest observed in 26 years, was observed in early February 1986 having just been preceded by a series of six solar flares during the period 3–7 February. The storm and its antecedent flares are currently a subject of great interest because of the unusually large magnitude of the various geomagnetic effects that obtained. The fact that the flares were moderate to large in soft X-ray intensity, but much smaller than the largest that the Sun is capable of producing, coupled with the fact that these events occurred near the minimum of the current solar activity cycle, adds to the uniqueness of the overall episode. This paper describes the special circumstances surrounding these events and offers an interpretation of the cause and effect relationships through a numerical simulation of the dynamical evolutionary processes that may have occurred in interplanetary space.  相似文献   

Are the small active regions related to the decay of the larger ones?     

J. I. De La Rosa Garcia 《Solar physics》1983,89(1):51-62

According to several properties, the active regions are divided in two groups whose limit is roughly set at 10²¹ Mx. A statistical analysis indicates that the small regions emerge almost exclusively in the remnant magnetic regions, resulting from the decay of previous active centers. According to these facts, a tentative picture is proposed, where the small active regions and perhaps also the ephemeral ones, are the secondary effects after the decay of the large active regions and complexes of activity.  相似文献   

Preface     

Michael Garcia  Robert W. Decker 《Bulletin of Volcanology》1980,43(4):625-625

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THERMAP: a mid-infrared spectro-imager for space missions to small bodies in the inner solar system     

O. Groussin  J. Licandro  J. Helbert  J. L. Reynaud  P. Levacher  M. Reyes García-Talavera  V. Alí-Lagoa  P. E. Blanc  E. Brageot  B. Davidsson  M. Delbó  M. Deleuze  A. Delsanti  J. J. Diaz Garcia  K. Dohlen  D. Ferrand  S. F. Green  L. Jorda  E. Joven Álvarez  J. Knollenberg  E. Kührt  P. Lamy  E. Lellouch  J. Le Merrer  B. Marty  G. Mas  C. Rossin  B. Rozitis  J. Sunshine  P. Vernazza  S. Vives 《Experimental Astronomy》2016,41(1-2):95-115

We present THERMAP, a mid-infrared spectro-imager for space missions to small bodies in the inner solar system, developed in the framework of the MarcoPolo-R asteroid sample return mission. THERMAP is very well suited to characterize the surface thermal environment of a NEO and to map its surface composition. The instrument has two channels, one for imaging and one for spectroscopy: it is both a thermal camera with full 2D imaging capabilities and a slit spectrometer. THERMAP takes advantage of the recent technological developments of uncooled microbolometer arrays, sensitive in the mid-infrared spectral range. THERMAP can acquire thermal images (8–18 μm) of the surface and perform absolute temperature measurements with a precision better than 3.5 K above 200 K. THERMAP can acquire mid-infrared spectra (8–16 μm) of the surface with a spectral resolution Δλ of 0.3 μm. For surface temperatures above 350 K, spectra have a signal-to-noise ratio >60 in the spectral range 9–13 μm where most emission features occur.  相似文献   

<Superscript>10</Superscript>Be surface exposure dating of the last deglaciation in the Aare Valley,Switzerland     

Lorenz Wüthrich  Ezequiel Garcia Morabito  Jana Zech  Mareike Trauerstein  Heinz Veit  Christian Gnägi  Silke Merchel  Andreas Scharf  Georg Rugel  Marcus Christl  Roland Zech 《Swiss Journal of Geoscience》2018,111(1-2):295-303

The combined Rhone and Aare Glaciers presumably reached their last glacial maximum (LGM) extent on the Swiss Plateau prior to 24 ka. Two well-preserved, less extensive moraine stades, the Gurten and Bern Stade, document the last deglaciation of the Aare Valley, yet age constraints are very scarce. In order to establish a more robust chronology for the glacial/deglacial history of the Aare Valley, we applied ¹⁰Be surface exposure dating on eleven boulders from the Gurten and Bern Stade. Several exposure ages are of Holocene age and likely document post-depositional processes, including boulder toppling and quarrying. The remaining exposure ages, however yield oldest ages of 20.7 ± 2.2 ka for the Gurten Stade and 19.0 ± 2.0 ka for the Bern Stade. Our results are in good agreement with published chronologies from other sites in the Alps.  相似文献   

Recent effects of tidal and hydro‐meteorological changes on coastal plains near the mouth of the Amazon River     

José Tasso Felix Guimarães  Marcelo Cancela Lisboa Cohen  Marlon Carlos França  Luiz Carlos Ruiz Pessenda  Eduardo de Jesus Souza  Afonso César Rodrigues Nogueira  Ronnie Alves 《地球表面变化过程与地形》2013,38(13):1535-1549

The goal of this work was to understand the main hydrodynamic processes acting on tidal flats of the coast of Amapá near the mouth of the Amazon River, and how they change over the short term (~ 20 years). The analysis of morphological and geobotanical units was carried out by applying processing and interpretation methods to optical and synthetic aperture radar (SAR) images, combined with data on water salinity, maximum flood height, sedimentary facies data, rainfall and river discharge. The temporal analysis of morphological and geobotanical units suggests the relative stabilization of savannah, ‘várzea’ and mangrove areas during the drier period and increasing tidal amplitude between 1987 to 1997. The wetter period and decreasing tidal amplitude between 1997 to 2008 led to an increase in the area of ‘várzea’ and lakes over savannah, and the expansion of mangroves mainly over the inundated field and tidal mud/mixed flats. Therefore, the decrease in rainfall index during the drier period is well‐correlated with the reduction of the Calçoene River discharge and jointly with increasing tidal amplitude favored the increase of migration rate of the mud bank and erosion profile along the littoral. It was followed by the increase of the Calçoene River discharge and jointly with decreasing tidal amplitude during the wetter period, favoring the development of mangroves on muddy substrates near the coastline. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Modulation of the flow structure by progressive bedforms in the Kinoshita meandering channel     

Jorge D. Abad  Christian E. Frias  Gustavo C. Buscaglia  Marcelo H. Garcia 《地球表面变化过程与地形》2013,38(13):1612-1622

An in‐house fully three‐dimensional general‐purpose finite element model is applied to solve the hydrodynamic structure in a periodic Kinoshita‐generated meandering channel. The numerical model solves the incompressible Reynolds‐averaged Navier–Stokes equations for mass and momentum, while solving the k ? ε equations for turbulence. The free surface is described by the rigid‐lid approximation (using measured water surface data) for flat (smooth‐bed) and self‐formed (rough‐bed) conditions. The model results are compared against experimental measurements in the ‘Kinoshita channel’, where three‐dimensional flow velocities and turbulence parameters were measured. This validation was carried out for the upstream‐valley meander bend orientation under smooth (flat bed) conditions. After validation, several simulations were carried out to predict the hydrodynamics in conditions where either it was not possible to perform measurements (e.g. applicability of the laboratory acoustic instruments) and to extrapolate the model to other planform configurations. For the flat smooth‐bed case, a symmetric (no skewness) planform configuration was modeled and compared to the upstream‐skewed case. For the self‐formed rough‐bed case, prediction of the hydrodynamics during the progression of bedforms was performed. It appears that the presence of bedforms on a bend has the following effects: (i) the natural secondary flow of the bend is disrupted by the presence of the bedforms, thus depending on the location of the dune, secondary flows might differ completely from the traditional orientation; (ii) an increment on both the bed and bank shear stresses is induced, having as much as 50% more fluvial erosion, and thus a potential increment on the migration rate of the bend. Implications on sediment transport and bend morphodynamics are also discussed in the paper. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献