Reconstruction of Tsunami Inland Propagation on December 26, 2004 in Banda Aceh, Indonesia, through Field Investigations     

Franck Lavigne  Raphaël Paris  Delphine Grancher  Patrick Wassmer  Daniel Brunstein  Franck Vautier  Frédéric Leone  François Flohic  Benjamin De Coster  Taufik Gunawan  Christopher Gomez  Anggri Setiawan  Rino Cahyadi  Fachrizal 《Pure and Applied Geophysics》2009,166(1-2):259-281

This paper presents the results from an extensive field data collection effort following the December 26, 2004 earthquake and tsunami in Banda Aceh, Sumatra. The data were collected under the auspices of TSUNARISQUE, a joint French-Indonesian program dedicated to tsunami research and hazard mitigation, which has been active since before the 2004 event. In total, data from three months of field investigations are presented, which detail important aspects of the tsunami inundation dynamics in Banda Aceh. These include measurements of runup, tsunami wave heights, flow depths, flow directions, event chronology and building damage patterns. The result is a series of detailed inundation maps of the northern and western coasts of Sumatra including Banda Aceh and Lhok Nga. Among the more important findings, we obtained consistent accounts that approximately ten separate waves affected the region after the earthquake; this indicates a high-frequency component of the tsunami wave energy in the extreme near-field. The largest tsunami wave heights were on the order of 35 m with a maximum runup height of 51 m. This value is the highest runup value measured in human history for a seismically generated tsunami. In addition, our field investigations show a significant discontinuity in the tsunami wave heights and flow depths along a line approximately 3 km inland, which the authors interpret to be the location of the collapse of the main tsunami bore caused by sudden energy dissipation. The propagating bore looked like a breaking wave from the landward side although it has distinct characteristics. Patterns of building damage are related to the location of the propagating bore with overall less damage to buildings beyond the line where the bore collapsed. This data set was built to be of use to the tsunami community for the purposes of calibrating and improving existing tsunami inundation models, especially in the analysis of extreme near-field events.  相似文献   

Hydrological and geochemical control of metals and arsenic in a Mediterranean river contaminated by acid mine drainage (the Amous River,France); preliminary assessment of impacts on fish (Leuciscus cephalus)     

Corinne Casiot  Marion Egal  Françoise Elbaz-Poulichet  Odile Bruneel  Chrystelle Bancon-Montigny  Marie-Ange Cordier  Elena Gomez  Catherine Aliaume 《Applied Geochemistry》2009

Dissolved and particulate concentrations of metals (Fe, Al, Mn, Co, Ni, Cu, Zn, Cd, Tl, Pb) and As were monitored over a 5 year period in the Amous River downstream of its confluence with a creek severely affected by acid mine drainage (AMD) originating from a former Pb–Zn mine. Water pH ranged from 6.5 to 8.8. Metals were predominantly in dissolved form, except Fe and Pb, which were in particulate form. In the particulate phase, metals were generally associated with Al oxides, whereas As was linked to Fe oxides. Metal concentrations in the dissolved and/or particulate phase were generally higher during the wet season due to higher generation of AMD. Average dissolved (size < 0.22 μm) metal concentrations (μg/L) were 1 ± 4 (Fe), 69 ± 49 (Al), 140 ± 118 (Mn), 4 ± 3 Co, 6 ± 4 (Ni), 1.3 ± 0.8 (Cu), 126 ± 81 (Zn), 1.1 ± 0.7 (Cd), 0.9 ± 0.5 (Tl), 2 ± 3 (Pb). Dissolved As concentrations ranged from 5 to 134 μg/L (30 ± 23 μg/L). During the survey, the concentration of colloidal metals (5 kDa < size < 0.22 μm) was less than 25% of dissolved concentrations. Dissolved metal concentrations were generally higher than the maximum concentrations allowed in European surface waters for priority substances (Ni, Cd and Pb) and higher than the environmental quality standards for other compounds. Using Diffusion Gradient in Thin Film (DGT) probes, metals were shown to be in potentially bioavailable form. The concentrations in Leuciscus cephalus were below the maximum Pb and Cd concentrations allowed in fish muscle for human consumption by the European Water Directive. Amongst the elements studied, only As, Pb and Tl were shown to bioaccumulate in liver tissue (As, Pb) or otoliths (Tl). Bioaccumulation of metals or As was not detected in muscle.  相似文献   

Transverse architecture of lahar terraces,inferred from radargrams: preliminary results from Semeru Volcano,Indonesia     

C. Gomez  F. Lavigne 《地球表面变化过程与地形》2010,35(9):1116-1121

Semeru Volcano is the highest mountain of Java (Indonesia), and a vulcanian explosion occurs every 15 minutes on average, since 1967. Thus a constantly renewed stock of material and the heavy monsoon rainfall [3700 mm yr^?1 at 1500 m above sea level (a.s.l.)] provide a perfect setting for the study of lahars and their deposits. Hence, we examined the architecture of lahars' terraces 9·5 km from the summit in the Curah Lengkong Valley. We first used ground penetrating radar (GPR) over vertical exposures of the lahars cut‐bank terraces. This allowed us to better understand transversal radargrams across terraces, which are not visually accessible in the field. Preliminary results from a single radargram are very instructive, since (1) they prove that the lateral architecture does not correspond to that observed from banks only; (2) we could observe the presence of lenses and stratigraphic discontinuities; (3) the setting of the various units can also help reconstruct deposition processes and the chronology of different units. In order to finalize these preliminary results, we however need to perform multiple GPR radargrams and provide a complete set of results. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Color variations of the blazar 3C 454.3 in 2004–2006     

V. A. Hagen-Thorn  N. V. Efimova  V. M. Larionov  C. M. Raiteri  M. Villata  A. A. Arkharov  E. I. Hagen-Thorn  C. A. Gomez  S. G. Jorstad  L. V. Larionova  L. O. Takalo  A. Sillanpää 《Astronomy Reports》2009,53(6):510-518

We present an analysis of multicolor (U BV RI JH K) observations of the blazar 3C 454.3 made in 2004–2006. We used the light curves compiled at the Turin Observatory from coordinated observations in the framework of the WEBT program. We consider color variations in two time intervals, when an unprecedented strong outburst occurred (2004–2005), and when the object was in a post-eruptive state and a low-amplitude brightness increase was observed (2006). The spectral energy distribution (SED) of the variable component remained the same within each of these intervals, but differed between them. In both cases, this SED followed a power law after correction for extinction, suggesting the variable component has a synchrotron nature. We conclude that the variations in the optical and IR were due to the same variable source. The object’s unusual color behavior (the brighter, the redder) was due to an increasing contribution from a variable component that was redder than the constant component (big blue bump).  相似文献   

Longitudinal structure of pyroclastic-flow deposits,revealed by GPR survey,at Merapi Volcano,Java, Indonesia     

C. Gomez  F. Lavigne  N. Lespinasse  D.S. Hadmoko  P. Wassmer 《Journal of Volcanology and Geothermal Research》2008

In 2006 Merapi volcano, Indonesia, erupted for a few months, producing several block-and-ash flows reaching a maximum distance of 7.5 km from the main vent. During the eruption, we conducted a survey on those flow deposits in the Gendol Valley at Kaliadem village, about 4.5 km from the Merapi submit, using a Ground Penetrating Radar (GPR). The upper deposit was studied in its distal reaches, whereas the one below was studied in its medial reaches. The field study was carried out with a commercial RAMAC® GPR coupled with 100 MHz antennas, and the data treatment conducted with Reflex™ software. From this survey, we determined both deposits' local (1) thickness – reaching a maximum of 15 m – and (2) internal architecture. This last one is governed by long reflecting horizons extending over 20 to 30 m that delimit layers showing progradation patterns in their distal reaches. Within these layers we could also observe an internal architecture of still unknown origin. The layers are interpreted as the result of the flow pulses that progressively deposited downstream-ward by progradation. However the interpretation of those GPR profiles is a bit hazardous, because of the absence of outcrops, and we can only proceed by analogy with other studies. Nevertheless, despite numerous limitations, GPR is a helpful tool to understand pyroclastic deposits' structure when no visual observations are available.  相似文献   

Tidal and annual variability of the population structure of Eurytemora affinis in the middle part of the Seine Estuary during 2005     

David Devreker  Sami Souissi  Juan Carlos Molinero  Delphine Beyrend-Dur  Fernando Gomez  Joelle Forget-Leray 《Estuarine, Coastal and Shelf Science》2010

Annual variability in abundance and population structure of the copepod Eurytemora affinis was studied in the maximum turbidity zone of the Seine Estuary in 2005. An Eulerian sampling strategy was applied monthly from March to July and from September to December. Chlorophyll a and suspended particulate matter (SPM) concentration, copepod abundance and stage distribution, and phytoplankton abundance were measured in sub-surface and near-bottom water during the ebb phase. Total E. affinis abundance was at a maximum in March and April (>200 × 10³ ind. m⁻³), and decreased from May to September (<25 × 10³ ind. m⁻³). This decrease corresponds to annual increases in temperature, salinity, chlorophyll a concentration and phytoplankton abundance, which was dominated by large diatoms, and decreases in SPM and river discharge. The phenology observed in 2005 was almost two months earlier compared to previous studies in the 1990s, when E. affinis reached maximum abundance in May and June. The low proportion of nauplii (<50%) in the population and high abundance of ovigerous females suggests that low recruitment is probably related to anomalously low temperatures in late winter (<5 °C). Whatever the horizontal position of the population in the estuary, adult and late copepodid stages are distributed in higher salinity than naupliar stages. Overall E. affinis population abundance was driven by parameters that characterize water masses at the tidal scale and by river discharge and chlorophyll a at the annual scale. By integrating the tidal effect, the high-frequency sampling protocol used appears to be optimal for investigating annual variability of planktonic communities in megatidal estuaries.  相似文献   

Simple Model of a Stochastically Excited Solar Dynamo   总被引：2，自引：0，他引：2  

Pablo D. Mininni  Daniel O. Gomez  Gabriel B. Mindlin 《Solar physics》2001,201(2):203-223

The aim of this paper is to investigate the dynamical nature of the complexity observed in the time evolution of the sunspot number. We report a detailed analysis of the sunspot number time series, and use the daily records to build the phase space of the underlying dynamical system. The observed features of the phase space prompted us to describe the global behavior of the solar cycle in terms of a noise-driven relaxation oscillator. We find the equations whose solutions best fit the observed series, which adequately describe the shape of the peaks and the oscillations of the system. The system of equations obtained from this fitting procedure is shown to be equivalent to a truncation of the dynamo equations. A linear transformation maps the phase space of these equations into the phase space reconstructed from the observations. The irregularities of the solar cycle were modeled through the introduction of a stochastic parameter in the equations to simulate the randomness arising in the process of eruption of magnetic flow to the solar surface. The mean values and deviations obtained for the periods, rise times and peak values, are in good agreement with the values obtained from the sunspot time series.  相似文献   

Integrated remote sensing and GIS techniques for biogeochemical characterization of the Tinto-Odiel estuary system,SW Spain     

M.?Chica-OlmoEmail author  F.?Rodriguez  F.?Abarca  J.?P.?Rigol-Sanchez  E.?deMiguel  J.?A.?Gomez  A.?Fernandez-Palacios 《Environmental Geology》2004,45(6):834-842

The Tinto-Odiel estuary area in SW Spain presents a high concentration of industrial, agricultural and mining activities that seriously affect water quality, producing significant concentrations in trace metals and other contaminant elements. Previous studies have highlighted the important environmental effect of these contaminated waters discharged into the Gulf of Cadiz, contributing in a marked way to trace-metal concentrations in the Mediterranean Sea by water inflow through the Strait of Gibraltar. A global biogeochemical characterization of these waters was the main objective of a multidisciplinary research study funded by the European Union, in which remote sensing and GIS techniques, among other methodologies, were jointly applied. The main results confirmed the usefulness of this integrated methodological approach as an effective tool for the assessment of current biogeochemical conditions. Digital image processing provided valuable thematic information for temporal hydrodynamic analysis and water quality parameters mapping, which was integrated into a GIS database together with experimental information sampled in oceanographic cruises.  相似文献   

The concentrations of selected trace elements in clams, Trivela mactroidea along the Venezuelan coast in the state of Miranda     

LaBrecque JJ  Benzo Z  Alfonso JA  Cordoves PR  Quintal M  Gomez CV  Marcano E 《Marine pollution bulletin》2004,49(7-8):664-667

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Fresnel arrays and their astrophysical applications     

Laurent Koechlin  Jean-Pierre Rivet  Ana Ines Gomez de Castro 《Experimental Astronomy》2011,30(2-3):83-84

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