scholarly journals The CSMS (Configurable Seismic Monitoring System) Poorboy deployment: Seismic recording in Pinedale, Wyoming, of the Bullion NTS (Nevada Test Site) nuclear test under the verification provisions of the new TTBT protocol

1990 ◽  
Author(s):  
P.E. Harben ◽  
D.W. Rock ◽  
R.C. Carlson

2018 ◽  
Author(s):  
Peter Gaebler ◽  
Lars Ceranna ◽  
Nima Nooshiri ◽  
Andreas Barth ◽  
Simone Cesca ◽  
...  

Abstract. On September 3rd 2017 official channels of the Democratic People's Republic of Korea announced the successful test of a thermonuclear device. Only seconds to minutes after the alleged nuclear explosion at the Punggye-ri nuclear test site in the mountainous region in the country's northeast at 03:30:02 (UTC) hundreds of seismic stations distributed all around the globe picked up strong and distinct signals associated with an explosion. Different seismological agencies reported body wave magnitudes of well above 6.0, consequently estimating the explosive yield of the device in the order of hundreds of kilotons TNT equivalent. The 2017 event can therefore be assessed being multiple times larger in energy than the two preceding events in January and September 2016. This study provides a multi-technology analysis of the 2017 North Korean event and its aftermath using a wide array of geophysical methods. Seismological investigations locate the event within the test site at a depth of approximately 0.8 km below surface. The radiation and generation of P- and S-wave energy in the source region is significantly influenced by the topography of the Mt. Mantap massif. Inversions for the full moment tensor of the main event reveal a dominant isotropic component accompanied by significant amounts of double couple and compensated linear vector dipole terms, confirming the explosive character of the event. Analysis of the source mechanism of an aftershock that occurred around eight minutes after the test in the direct vicinity suggest a cavity collapse. Measurements at seismic stations of the International Monitoring System result in a body wave magnitude of 6.2, which translates to an yield estimate of around 400 kilotons TNT equivalent. The explosive yield is possibly overestimated, since topography and depth phases both tend to ehance the peak amplitudes of teleseismic P-waves. Interferometric Synthetic-Aperture-Radar analysis using data from the ALOS-2 satellite reveal strong surface deformations in the epicenter region. Additional multispectral optical data from the Pleiades satellite show clear landslide activity at the test site. The strong surface deformations generated large acoustic pressure peaks, which were observed as infrasound signals with distinctive waveforms even in distances of 400 km. In the aftermath of the 2017 event atmospheric traces of the fission product 133Xe have been detected at various locations in the wider region. While for 133Xe measurements in September 2017 the Punggye-ri test site is disfavored as source by means of atmospheric transport modeling, detections in October 2017 at the International Monitoring System station RN58 in Russia indicate a potential delayed leakage of 133Xe at the test site from the 2017 North Korean nuclear test.





Author(s):  
D. S. Shafer ◽  
J. B. Chapman ◽  
A. E. Hassan ◽  
G. Pohll ◽  
K. F. Pohlmann ◽  
...  

Characterizing and managing groundwater contamination associated with the 828 underground nuclear tests conducted at the Nevada Test Site are among the most challenging environmental remediation issues faced by the U.S. Department of Energy. Although significant long-term stewardship and risk management issues are associated with underground nuclear tests on the Nevada Test Site, of possible equal concern are a smaller number of underground nuclear tests conducted by the United States, 12 total, at eight sites located off the Nevada Test Site. In comparison to the Nevada Test Site, the U.S. Department of Energy has minimal institutional controls at these “offsite test areas” (Offsites) to serve as risk barriers. The corrective action and closure strategy under development for the Central Nevada Test Area and proposed recommendations [1] concerning long-term stewardship for this and the other Offsites illustrate long-term stewardship and risk management strategies applicable to underground nuclear test areas in the United States. The groundwater flow and transport model for the Central Nevada Test Area, site of the 1968 Faultless underground nuclear test, is the first model accepted by a U.S. state regulator (the Nevada Division of Environmental Protection) for an underground nuclear test area. Recommendations for the Central Nevada Test Area and other Offsites include developing decision support models to evaluate the impacts of future changes of land and water uses on previous decisions involving groundwater-use restrictions. Particularly for the Offsites in arid states such as Nevada, New Mexico, and Colorado, it is difficult to envision all future demands on subsurface resources. Rather than trying to maintain complex flow and transport models to evaluate future resource-use scenarios, decision support models coupled with original contaminant flow and transport models could be used as scoping tools to evaluate the sensitivity of previously established resource-use boundaries. This evaluation will determine if the previously established boundaries are still adequate for proposed new land and resource uses or if additional data collection or modeling will be necessary to make technically sound decisions. In addition, previously developed Data Decision Analyses, used to quantitatively evaluate the costs and benefits of different data collection activities conducted during the site characterization phase, could be maintained as a long-term stewardship tool to identify new data collection efforts, if necessary as indicated by a decision support model.



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