scholarly journals Rn and CO<sub>2</sub> geochemistry of soil gas across the active fault zones in the capital area of China

2014 ◽  
Vol 14 (10) ◽  
pp. 2803-2815 ◽  
Author(s):  
X. Han ◽  
Y. Li ◽  
J. Du ◽  
X. Zhou ◽  
C. Xie ◽  
...  

Abstract. The present work is proposed to investigate the spatiotemporal variations in soil gas Rn and CO2 across the active faults in the capital area of China in order to understand fault activities and assess seismic hazard. A total of 342 soil gas sampling sites were measured twice in 2011 and 2012 along seven profiles and across four faults. The results of soil gas surveys show that, in each profile, due to the variation in gas emission rate, the concentrations of Rn and CO2 changed in the vicinity of faults. Spatial distributions of Rn and CO2 in the study areas were different from each other, which was attributed to soil types affecting the existence of Rn and CO2. Compared with the measurement result of 2011, the increasing amplitude of average concentration value of Rn and CO2 in profiles in 2012 ranged from 30.2 to 123.4% and 66.3 to 131.7%, respectively, which were coincident with the enhancement of seismic activities in the capital area of China. Our results indicate that special attention with regard to seismic monitoring should be paid to the Xinbaoan–Shacheng Fault and the northeastern segment of the Tangshan Fault in the future.

2014 ◽  
Vol 2 (2) ◽  
pp. 1729-1757 ◽  
Author(s):  
X. Han ◽  
Y. Li ◽  
J. Du ◽  
X. Zhou ◽  
C. Xie ◽  
...  

Abstract. The present work is proposed to investigate the spatiotemporal variations of soil gas Rn and CO2 across the active faults in the capital area of China, for the understanding of fault activities and the assessment of seismic hazard. A total of 342 soil gas sampling sites were measured twice in 2011 and 2012 along seven profiles across four faults. The results of soil gas surveys show that in each profile, due to the variation of gas emission rate, the concentrations of Rn and CO2 changed in the vicinity of faults. Spatial distributions of Rn and CO2 in the study areas were different from each other, which was attributed to soil types affecting the existence of Rn and CO2. Compared with 2011 soil gas survey, the increases of Rn and CO2 concentrations in 2012 were related to the enhancement of seismic activities in the capital area of China. Our results indicate that special attention for seismic monitoring should be paid to Xinbaoan-Shacheng Fault and the north east segment of Tangshan Fault in the future.


2009 ◽  
Vol 46 (1) ◽  
pp. 102-113 ◽  
Author(s):  
Tai T. Wong ◽  
John G. Agar

Soil vapour intrusion is now commonly evaluated as part of human health risk assessments at contaminated sites where buildings or other structures are located in close proximity to volatile organic chemicals (VOCs) in subsurface soils and groundwater. Investigation of the vapour intrusion pathway often requires that VOC concentrations in the soil gas adjacent to buildings and structures be characterized as part of the risk assessment process. This paper presents the design of a new soil gas monitoring well and a sampling procedure that effectively eliminate concerns about soil gas sample dilution due to short-circuiting of atmospheric air and help to ensure the collection of representative soil gas samples. The results of a parametric numerical modelling study that was applied to address the air short-circuiting issue and the technical rationale for the new soil gas monitoring well (SGMW) design are presented in this paper along with recommended soil gas sampling procedures in various soil conditions. The SGMW design rationale and methodology outlined in this paper considered the effects of soil moisture content and permeability, the depth to the sampling screen interval, and the soil gas sample extraction rate.


2014 ◽  
Vol 56 (6) ◽  
Author(s):  
Ioannis G. Fountoulis ◽  
Spyridon D. Mavroulis

On September 13, 1986, a shallow earthquake (Ms=6.2) struck the city of Kalamata and the surrounding areas (SW Peloponnese, Greece) resulting in 20 fatalities, over 300 injuries, extensive structural damage and many earthquake environmental effects (EEE). The main shock was followed by several aftershocks, the strongest of which occurred two days later (Ms=5.4). The EEE induced by the 1986 Kalamata earthquake sequence include ground subsidence, seismic faults, seismic fractures, rockfalls and hydrological anomalies. The maximum ESI 2007 intensity for the main shock has been evaluated as IX<sub>ESI 2007</sub>, strongly related to the active fault zones and the reactivated faults observed in the area as well as to the intense morphology of the activated Dimiova-Perivolakia graben, which is a 2nd order neotectonic structure located in the SE margin of the Kalamata-Kyparissia mega-graben and bounded by active fault zones. The major structural damage of the main shock was selective and limited to villages founded on the activated Dimiova-Perivolakia graben (IX<sub>EMS-98</sub>) and to the Kalamata city (IX<sub>EMS-98</sub>) and its eastern suburbs (IX<sub>EMS-98</sub>) located at the crossing of the prolongation of two major active fault zones of the affected area. On the contrary, damage of this size was not observed in the surrounding neotectonic structures, which were not activated during this earthquake sequence. It is concluded that both intensity scales fit in with the neotectonic regime of the area. The ESI 2007 scale complemented the EMS-98 seismic intensities and provided a completed picture of the strength and the effects of the September 13, 1986, Kalamata earthquake on the natural and the manmade environment. Moreover, it contributed to a better picture of the earthquake scenario and represents a useful and reliable tool for seismic hazard assessment.


1987 ◽  
Vol 1987 (1) ◽  
pp. 605-610
Author(s):  
Victor H. Owens ◽  
Walter J. Sexton ◽  
Jacqueline Michel

ABSTRACT Underground oil spills leaking into navigable waterways at Baltimore, Maryland, and Hilo, Hawaii, were investigated using soil-gas sampling methods. Gas extraction methods were used in Hilo with mixed but favorable results. Component adsorption methods were used in Baltimore with highly favorable results. In comparing the two soil-gas sampling methods and results, the component adsorption method was found to be superior in detecting the presence or absence of underground diesel oil. The gas extraction method produced results that were somewhat limited in use because of lack of sensitivity to the components of diesel oil. Interpretation of data from both methods was found to be complicated by the presence of surface spill contamination leading to false indications of underground oil.


2012 ◽  
Author(s):  
J. Noonkester ◽  
D. Jackson ◽  
W. Jones ◽  
W. Hyde ◽  
J. Kohn ◽  
...  

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