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141.
Ihsane Bensaid Taj-Eddine Cherkaoui Fida Medina Bento Caldeira Elisa Buforn Anas Emran Youssef Hahou 《Journal of Seismology》2012,16(1):35-53
The Tafilalt region, located at the eastern end of the Anti-Atlas chain in Morocco, was shaken on 23 and 30 October 1992 by
two moderate earthquakes of magnitude mb ∼ 5 and intensity ∼ VI MSK64, which caused two deaths and great damage in the area between Erfoud and Rissani. The review
of data available on the seismic crisis allowed us to improve the knowledge on the macroseismic, instrumental and source parameters
of the earthquakes. The main results of the present study are: (1) location of the epicentres with the help of data from a
close portable network allowed us to propose new epicentral coordinates at 31.361° N, 4.182° W (23 October) and 31.286° N,
4.347° W (30 October); both events have focal depths of 2 km; (2) the shock of 30 October was followed by a series of 305
aftershocks, most of which were located west of Rissani; the 61 best-constrained events had focal depths of 5 to 19 km and
magnitudes 0.7 to 3; (3) the largest damage was located in an area between the two epicentres within the Tafilalt valley and
was probably amplified by site effects due to the proximity of the water table within the Quaternary sediments; (4) focal
mechanisms of the main events correspond to strike-slip faulting with fault planes oriented N–S (left lateral) and E–W (right
lateral); the only mechanism available for the aftershocks also corresponds to strike-slip faulting; (5) spectral analysis
shows that the scalar seismic moment (Mo) of the first event is slightly larger than the second; the corresponding values of Mw are 5.1 and 5.0, respectively; (6) the dimensions of the faults for a circular fault model are 7.7 ± 1.4 and 7.4 ± 1.2 km,
respectively; the average displacement is 4 cm for the first event and 3.7 cm for the second; the stress drop is 0.4 and 0.3 MPa,
respectively, in agreement with standard values; (7) the Coulomb Stress test performed for both earthquakes suggests a relationship
between both events only when the used location is at the limit of the horizontal uncertainty; (8) finally, the occurrence
of these shocks suggests that the Anti-Atlas is undergoing tectonic deformation in addition to thermal uplift as suggested
by recent publications. 相似文献
142.
Elisa Zuccolo Tony Gibbs Carlo G. Lai Joan L. Latchman Walter Salazar Luigi Di Sarno Anthony Farrell Lloyd Lynch Addison Workman 《Bulletin of Earthquake Engineering》2016,14(9):2579-2605
A feasibility study of an earthquake early warning (EEW) system was conducted for the Eastern Caribbean region using scenario earthquakes, corresponding to the maximum credible earthquakes and to the earthquakes associated with a return period of 475 years. Broadband synthetic seismograms were produced at selected critical facilities, where there is potential interest in the installation of an EEW system. The expected damage was derived from the synthetic seismograms and compared with the lead-time determined for both a regional and on-site EEW configuration. Next, the Virtual Seismologist EEW algorithm, as included in SeisComP3, was tested. Additional broadband synthetic seismograms were produced for the stations in the Eastern Caribbean seismic networks in order to simulate the real time behaviour of the seismic networks during the occurrence of the synthetic earthquakes and to assess the predictive capacity of the selected ground motion prediction equation. Expected peak ground parameters and lead-times at the critical facilities constitute the major outcome of the study. 相似文献
143.
Lyuba Moroz Giuseppe Baratta Larissa Starukhina Maria Antonietta Barucci Elisa Distefano 《Icarus》2004,170(1):214-228
Most ion irradiation experiments relevant to primitive outer Solar System objects have been performed on ice and silicate targets. Here we present the first ion irradiation experiments performed on natural complex hydrocarbons (asphaltite and kerite). These materials are very dark in the visible and have red-sloped spectra in the visible and near-infrared. They may be comparable in composition and structure to refractory organic solids on the surfaces of primitive outer Solar System objects. We irradiated the samples with 15-400 keV H+, N+, Ar++, and He+ ions and measured their reflectance spectra in the range of 0.3-2.5 μm before ion implantation and after each irradiation step. The results show that irradiation-induced carbonization gradually neutralizes the spectral slopes of these red organic solids. This implies a similar space weathering trend for the surfaces of airless bodies optically dominated by spectrally red organic components. The reduction of spectral slope was observed in all experiments. Irradiation with 30 keV protons, which transfers energy to the target mostly via electronic (inelastic) collisions, showed lower efficiency than the heavier ions. We found that spectral alteration in our experiments increased with increasing contribution of nuclear versus electronic energy loss. This implies that nuclear (elastic) energy deposition plays an important role in changing the optical properties of irradiated refractory complex hydrocarbon materials. Finally, our results indicated that temperature variations from 40 K to room temperature did not influence the spectral properties of these complex hydrocarbon solids. 相似文献
144.
Elisa Sacchi Jean-Luc Michelot Helmut Pitsch Philippe Lalieux Jean-François Aranyossy 《Hydrogeology Journal》2001,9(1):17-33
This paper summarises the results of a comprehensive critical review, initiated by the OECD/NEA "Clay Club," of the extraction
techniques available to obtain water and solutes from argillaceous rocks. The paper focuses on the mechanisms involved in
the extraction processes, the consequences on the isotopic and chemical composition of the extracted pore water and the attempts
made to reconstruct its original composition. Finally, it provides some examples of reliable techniques and information, as
a function of the purpose of the geochemical study.
Electronic Publication 相似文献
145.
Elisa Sainz de Murieta Pedro P. Cunha Alejandro Cearreta Andrew S. Murray Jan-Pieter Buylaert 《第四纪科学杂志》2021,36(4):570-585
A detailed study is presented of a 15.3-m-thick Pleistocene coastal terrace located on the Cantabrian coast (northern Spain). Stratigraphic, sedimentological, topographic and micropalaeontological information is combined with a chronology based on luminescence dating to characterize the deposits. The sedimentary succession records: (i) a basal transgressive system, consisting of a wave-cut surface covered by a lower layer of beach gravels and upper beach pebbly sands; and (ii) a thicker upper highstand system (aggrading), comprising medium to very fine aeolian sands interbedded with thin palustrine muds. Luminescence dating involved a detailed sampling strategy (36 samples and two modern analogues) and the use of both quartz optically stimulated luminescence (OSL) and feldspar post-infrared infrared stimulated luminescence single aliquot regeneration protocols; feldspar results were used to confirm the completeness of bleaching of the quartz OSL signal. The quartz OSL luminescence age–depth relationship shows significant dispersion, but nevertheless two rapid phases of deposition can be clearly identified: one at ~130 ka [Marine Oxygen Isotope Stage (MIS) 5] and one at ~100 ka (MIS 5c). The top of the succession is dated to ~70 ka. The MIS 5e marine maximum flooding surface is identified at an elevation of 6.85 m above mean seal level. This elevation provides evidence of a regional sea-level highstand for this sector of the Cantabrian coast. 相似文献
146.
Paolo Davini Chiara Cagnazzo Pier Giuseppe Fogli Elisa Manzini Silvio Gualdi Antonio Navarra 《Climate Dynamics》2014,43(1-2):71-85
The relationship between atmospheric blocking over Europe and the Atlantic eddy-driven jet stream is investigated in the NCEP/NCAR Reanalysis and in a climate model. This is carried out using a bidimensional blocking index based on geopotential height and a diagnostic providing daily latitudinal position and strength of the jet stream. It is shown that European Blocking (EB) is not decoupled from the jet stream but it is mainly associated with its poleward displacements. Moreover, the whole blocking area placed on the equatorward side of the jet stream, broadly ranging from Azores up to Scandinavia, emerges as associated with poleward jet displacements. The diagnostics are hence applied to two different climate model simulations in order to evaluate the biases in the jet stream and in the blocking representation. This analysis highlights large underestimation of EB, typical feature of general circulation models. Interestingly, observed blocking and jet biases over the Euro-Atlantic area are consistent with the blocking-jet relationship observed in the NCEP/NCAR Reanalysis. Finally, the importance of sea surface temperatures (SSTs) is investigated showing that realistic SSTs can reduce the bias in the jet stream variability but not in the frequency of EB. We conclude highlighting that blocking-related diagnostics can provide more information about the Euro-Atlantic variability than diagnostics simply based on the Atlantic jet stream. 相似文献
147.
148.
Margaret M. Hurwitz Natalia Calvo Chaim I. Garfinkel Amy H. Butler Sarah Ineson Chiara Cagnazzo Elisa Manzini Cristina Peña-Ortiz 《Climate Dynamics》2014,43(12):3367-3376
The seasonal mean extra-tropical atmospheric response to El Niño/Southern Oscillation (ENSO) is assessed in the historical and pre-industrial control CMIP5 simulations. This analysis considers two types of El Niño events, characterized by positive sea surface temperature (SST) anomalies in either the central equatorial Pacific (CP) or eastern equatorial Pacific (EP), as well as EP and CP La Niña events, characterized by negative SST anomalies in the same two regions. Seasonal mean geopotential height anomalies in key regions typify the magnitude and structure of the disruption of the Walker circulation cell in the tropical Pacific, upper tropospheric ENSO teleconnections and the polar stratospheric response. In the CMIP5 ensembles, the magnitude of the Walker cell disruption is correlated with the strength of the mid-latitude responses in the upper troposphere i.e., the North Pacific and South Pacific lows strengthen during El Niño events. The simulated responses to El Niño and La Niña have opposite sign. The seasonal mean extra-tropical, upper tropospheric responses to EP and CP events are indistinguishable. The ENSO responses in the MERRA reanalysis lie within the model scatter of the historical simulations. Similar responses are simulated in the pre-industrial and historical CMIP5 simulations. Overall, there is a weak correlation between the strength of the tropical response to ENSO and the strength of the polar stratospheric response. ENSO-related polar stratospheric variability is best simulated in the “high-top” subset of models with a well-resolved stratosphere. 相似文献