This paper focuses on the impact of past mining on public safety.It emphasizes the need to understand the induced seismic hazard and consequently improve the post-mining management procedures and legislations,as many ...This paper focuses on the impact of past mining on public safety.It emphasizes the need to understand the induced seismic hazard and consequently improve the post-mining management procedures and legislations,as many mining sites are located in proximity to populated areas.Due to many challenges and complexity of the post-mining environments,induced seismic hazard nowadays remains largely unknown.However,the return experience of several post-mining sites in recent decades have shown us that the mine flooding and/or degradation of mining works can lead to the stress perturbations,inducing the seismicity and the reactivation of the surrounding geological faults.Hence,it is important to advance the seismic monitor-ing and research of seismicity in flooded post-mining districts.As the number of mine closures worldwide is rising,it can be expected that flooding induced reactivation of the surrounding faults becomes a more often observed phenomenon.We present in this paper the experience of the abandoned flooded coal mine of Gardanne in France,which has been experiencing post-mining seismicity problems since its closure in 2010.We show the results of a recent study of seismic multiplets and clustering of seismic events,as well as their spatio-temporal activity compared to meteorological conditions.These results provide us new insights as well as lead to raising new questions on seismic sources and triggering mechanisms.展开更多
Molecular speciation of atmospheric organic matter was investigated during a short summer field campaign performed in a citrus fruit field in northern Corsica（June 2011）. Aimedat assessing the performance on the fie...Molecular speciation of atmospheric organic matter was investigated during a short summer field campaign performed in a citrus fruit field in northern Corsica（June 2011）. Aimedat assessing the performance on the field of newly developed analytical protocols, this work focuses on the molecular composition of both gas and particulate phases and provides an insight into partitioning behavior of the semi-volatile oxygenated fraction. Limonene ozonolysis tracers were specifically searched for, according to gas chromatography–mass spectrometry（GC–MS） data previously recorded for smog chamber experiments. A screening of other oxygenated species present in the field atmosphere was also performed. About sixty polar molecules were positively or tentatively identified in gas and/or particle phases. These molecules comprise a wide range of branched and linear, mono and di-carbonyls（C_3–C7）,mono and di-carboxylic acids（C_3–C_18）, and compounds bearing up to three functionalities.Among these compounds, some can be specifically attributed to limonene oxidation and others can be related to α- or β-pinene oxidation. This provides an original snapshot of the organic matter composition at a Mediterranean site in summer. Furthermore, for compounds identified and quantified in both gaseous and particulate phases, an experimental gas/particle partitioning coefficient was determined. Several volatile products, which are not expected in the particulate phase assuming thermodynamic equilibrium, were nonetheless present in significant concentrations. Hypotheses are proposed to explain these observations, such as the possible aerosol viscosity that could hinder the theoretical equilibrium to be rapidly reached.展开更多
文摘This paper focuses on the impact of past mining on public safety.It emphasizes the need to understand the induced seismic hazard and consequently improve the post-mining management procedures and legislations,as many mining sites are located in proximity to populated areas.Due to many challenges and complexity of the post-mining environments,induced seismic hazard nowadays remains largely unknown.However,the return experience of several post-mining sites in recent decades have shown us that the mine flooding and/or degradation of mining works can lead to the stress perturbations,inducing the seismicity and the reactivation of the surrounding geological faults.Hence,it is important to advance the seismic monitor-ing and research of seismicity in flooded post-mining districts.As the number of mine closures worldwide is rising,it can be expected that flooding induced reactivation of the surrounding faults becomes a more often observed phenomenon.We present in this paper the experience of the abandoned flooded coal mine of Gardanne in France,which has been experiencing post-mining seismicity problems since its closure in 2010.We show the results of a recent study of seismic multiplets and clustering of seismic events,as well as their spatio-temporal activity compared to meteorological conditions.These results provide us new insights as well as lead to raising new questions on seismic sources and triggering mechanisms.
文摘Molecular speciation of atmospheric organic matter was investigated during a short summer field campaign performed in a citrus fruit field in northern Corsica（June 2011）. Aimedat assessing the performance on the field of newly developed analytical protocols, this work focuses on the molecular composition of both gas and particulate phases and provides an insight into partitioning behavior of the semi-volatile oxygenated fraction. Limonene ozonolysis tracers were specifically searched for, according to gas chromatography–mass spectrometry（GC–MS） data previously recorded for smog chamber experiments. A screening of other oxygenated species present in the field atmosphere was also performed. About sixty polar molecules were positively or tentatively identified in gas and/or particle phases. These molecules comprise a wide range of branched and linear, mono and di-carbonyls（C_3–C7）,mono and di-carboxylic acids（C_3–C_18）, and compounds bearing up to three functionalities.Among these compounds, some can be specifically attributed to limonene oxidation and others can be related to α- or β-pinene oxidation. This provides an original snapshot of the organic matter composition at a Mediterranean site in summer. Furthermore, for compounds identified and quantified in both gaseous and particulate phases, an experimental gas/particle partitioning coefficient was determined. Several volatile products, which are not expected in the particulate phase assuming thermodynamic equilibrium, were nonetheless present in significant concentrations. Hypotheses are proposed to explain these observations, such as the possible aerosol viscosity that could hinder the theoretical equilibrium to be rapidly reached.
