Alteration of natural ³⁷Ar activity concentration in the subsurface by gas transport and water infiltration

High ³⁷Ar activity concentration in soil gas is proposed as a key evidence for the detection of underground nuclear explosion by the Comprehensive Nuclear Test-Ban Treaty. However, such a detection is challenged by the natural background of ³⁷Ar in the subsurface, mainly due to Ca activation by cosmic rays. A better understanding and improved capability to predict ³⁷Ar activity concentration in the subsurface and its spatial and temporal variability is thus required. A numerical model integrating ³⁷Ar production and transport in the subsurface is developed, including variable soil water content and water infiltration at the surface. A parameterized equation for ³⁷Ar production in the first 15 m below the surface is studied, taking into account the major production reactions and the moderation effect of soil water content. Using sensitivity analysis and uncertainty quantification, a realistic and comprehensive probability distribution of natural ³⁷Ar activity concentrations in soil gas is proposed, including the effects of water infiltration. Site location and soil composition are identified as the parameters allowing for a most effective reduction of the possible range of ³⁷Ar activity concentrations. The influence of soil water content on ³⁷Ar production is shown to be negligible to first order, while ³⁷Ar activity concentration in soil gas and its temporal variability appear to be strongly influenced by transient water infiltration events. These results will be used as a basis for practical CTBTO concepts of operation during an OSI.

Transport and fate of contaminants in the subsurface.

Mode of access: Internet.

Integrated use of surface-geophysical methods to indicate subsurface fractures at Milford, New Hampshire /

Includes bibliographical references (p. 36-38).

The musical scale of the Arabs. Medieval organ pipes and their bearing on the history of the scale. The natural diatonic scale.

From the Proceedings of the American Association for the Advancement of Science, v. 48, 1899.

Environmental assessment of subsurface disposal of municipal wastewater treatment sludge : interim report ; prepared by Ronald Lofy.

"A current report on solid waste management"--Cover.

Identifying sources of subsurface nitrate pollution with stable nitrogen isotopes /

"Contract no. 68-03-2450."

The prevalence of subsurface migration of hazardous chemical substances at selected industrial waste land disposal sites.

Issued Oct. 1977.

Processes affecting subsurface transport of leaking underground tank fluids /

"CR 810052."

Patent artificial slate manufactory, Woodford Bridge, Essex : for covering roofs, fronts of houses, and bricks : also water pipes and gutters.

Amendment leaf between p. 16-17.

Joint materials for vitrified clay pipes /

"These Studies deal with current activities in the department of Civil Engineering. They serve as progress reports of major investigations, and in general as a means for disseminating information not readily adaptable for presentation in formal technical papers or bulletins."

Pollution of subsurface water by sanitary landfills : volume 1 /

"Volumes 2 and 3, which are compilations of the experimental data collected, will be available through the National Technical Information Service, Springfield, Virginia 22151."

Engineering data on flow of fluids in pipes and heat transmission.

Mode of access: Internet.