Quantitative assessment to the impact of InSAR ionospheric and tropospheric corrections on source parameter modelling: application to the 4th nuclear test, North Korea

2020 ◽  
Vol 224 (1) ◽  
pp. 86-99
Author(s):  
Meng Zhu ◽  
Qiming Zeng ◽  
Jian Jiao
Keyword(s):  
Standard Deviation ◽  
Focal Mechanism ◽  
Quantitative Assessment ◽  
Nuclear Explosion ◽  
Nuclear Test ◽  
Focal Mechanism Solution ◽  
Atmospheric Effects ◽  
Underground Nuclear Explosion ◽  
Tropospheric Corrections ◽  
The Impact

SUMMARY Although many studies have revealed that the atmospheric effects of electromagnetic wave propagation (including ionospheric and tropospheric water vapour) have serious impacts on Interferometric Synthetic Aperture Radar (InSAR) measurement results, atmospheric corrections have not been thoroughly and comprehensively investigated in many well-known cases of InSAR focal mechanism solutions, which means there is no consensus on whether atmospheric effects will affect the InSAR focal mechanism solution. Moreover, there is a lack of quantitative assessment on how much the atmospheric effect affects the InSAR focal mechanism solution. In this paper, we emphasized that it was particularly important to assess the impact of InSAR ionospheric and tropospheric corrections on the underground nuclear explosion modelling quantitatively. Therefore, we investigated the 4th North Korea (NKT-4) underground nuclear test using ALOS-2 liters-band SAR images. Because the process of the underground nuclear explosion was similar to the volcanic magma source activity, we modelled the ground displacement using the Mogi model. Both the ionospheric and tropospheric phase delays in the interferograms were investigated. Furthermore, we studied how the ionosphere and troposphere phase delays could bias the estimation of Mogi source parameters. The following conclusions were drawn from our case study: the ionospheric delay correction effectively mitigated the long-scale phase ramp in the full-frame interferogram, the standard deviation decreased from 1.83 to 0.85 cm compared to the uncorrected interferogram. The uncorrected estimations of yield and depth were 8.44 kt and 370.33 m, respectively. Compared to the uncorrected estimations, the ionospheric correction increased the estimation of yield and depth to 9.43 kt and 385.48 m, while the tropospheric correction slightly raised them to 8.78 kt and 377.24 m. There were no obvious differences in the location estimations among the four interferograms. When both corrections were applied, the overall standard deviation was 1.16 cm, which was even larger than the ionospheric corrected interferogram. We reported the source characteristics of NKT-4 based on the modelling results derived from the ionospheric corrected interferogram. The preferred estimation of NKT-4 was a Mogi source located at 129°04′22.35‘E, 41°17′54.57″N buried at 385.48 m depth. The cavity radius caused by the underground explosion was 22.66 m. We reported the yield estimation to be 9.43 kt. This study showed that for large-scale natural deformation sources such as volcanoes and earthquakes, atmospheric corrections would be more significant, but even if the atmospheric signal did not have much complexity, the corrections should not be ignored.

On the Indicators of the Radioecological Situation at the Mid-Botuobin Oil and Gas Condensate Field with Underground Nuclear Explosions

2020 ◽  
Vol 24 (1) ◽  
pp. 56-61 ◽  
Author(s):  
V.E. Stepanov ◽  
V.D. Yakovleva ◽  
E.V. Sleptsova
Keyword(s):  
Industrial Development ◽  
Oil And Gas ◽  
Nuclear Explosion ◽  
Underground Nuclear Explosion ◽  
Laboratory Studies ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions ◽  
Radionuclide Composition ◽  
The Impact ◽  
Impact Zones

The results of expeditionary and laboratory studies of the radiation situation of 2001–2002 and dosimetry measurements of 2017 are presented. there are small radioactive spots. The radionuclide composition in the soil-vegetation cover of the impact zones of the underground nuclear explosion has been studied. Data obtained prior to the industrial development of the field are reperator for further radioecological research and can be used by subsoil users in the development of the area.

Theoretical signature of a cavern created by an underground nuclear explosion in 2-D exploration seismic data

2020 ◽  
Vol 221 (3) ◽  
pp. 1789-1801
Author(s):  
Stephany Ortiz-Aguilar ◽  
Jonas D De Basabe ◽  
Mario Gonzalez-Escobar ◽  
Vanesa Magar
Keyword(s):  
Seismic Data ◽  
Nuclear Explosion ◽  
Spectral Element ◽  
Nuclear Test ◽  
Underground Nuclear Explosion ◽  
Nuclear Explosions ◽  
Quadrilateral Elements ◽  
Safety And Health ◽  
The Time Domain ◽  
Test Ban

SUMMARY The proliferation of nuclear tests is a problem that threatens the safety and health of everybody. In order to tackle this problem, the UN is promoting the Comprehensive Nuclear-Test-Ban Treaty (CTBT), which includes protocols for monitoring and On-Site Inspections (OSI). The purpose of OSI is to verify if a nuclear test has been carried out by identifying with a geophysical technique the presence of a cavern, hole or some device that indicates the violation of the treaty. In this context, it is desirable to be able to use exploration-seismology techniques to detect caverns created by an underground nuclear explosion. However, there is scarce information about the seismic signature of this type of cavern. We present the results of elastic wave propagation simulations, in the time domain, with a cavern created by an underground nuclear explosion. The wave equation is solved using the spectral element method with 4th order basis functions and quadrilateral elements. We show the results for models with cavities and caverns corresponding to explosions of 1, 20 and 100 kilotons, and obtain seismic traces in which we can observe the effect of the structures. We conclude that caverns created by nuclear explosions can be detected using seismic data and distinguished from caves because they behave like two concentric diffractor bodies, as opposed to caves-like diffractors.

scholarly journals Dense Seismic Array Study of a Legacy Underground Nuclear Test at the Nevada National Security Site

2020 ◽  
Author(s):  
Evans Awere Onyango ◽  
Robert E. Abbott ◽  
Lindsay L. Worthington ◽  
Leiph A. Preston
Keyword(s):  
National Security ◽  
Seismic Data ◽  
Nuclear Explosion ◽  
Damage Zone ◽  
Nuclear Test ◽  
P Wave ◽  
Burial Depth ◽  
Underground Nuclear Explosion ◽  
Velocity Anomaly ◽  
Weight Drop

ABSTRACT The complex postdetonation geologic structures that form after an underground nuclear explosion are hard to constrain because increased heterogeneity around the damage zone affects seismic waves that propagate through the explosion site. Generally, a vertical rubble-filled structure known as a chimney is formed after an underground nuclear explosion that is composed of debris that falls into the subsurface cavity generated by the explosion. Compared with chimneys that collapse fully, leaving a surface crater, partially collapsed chimneys can have remnant subsurface cavities left in place above collapsed rubble. The 1964 nuclear test HADDOCK, conducted at the Nevada test site (now the Nevada National Security Site), formed a partially collapsed chimney with no surface crater. Understanding the subsurface structure of these features has significant national security applications, such as aiding the study of suspected underground nuclear explosions under a treaty verification. In this study, we investigated the subsurface architecture of the HADDOCK legacy nuclear test using hybrid 2D–3D active source seismic reflection and refraction data. The seismic data were acquired using 275 survey shots from the Seismic Hammer (a 13,000 kg weight drop) and 65 survey shots from a smaller accelerated weight drop, both recorded by ∼1000 three-component 5 Hz geophones. First-arrival, P-wave tomographic modeling shows a low-velocity anomaly at ∼200  m depth, likely an air-filled cavity caused by partial collapse of the rock column into the temporary postdetonation cavity. A high-velocity anomaly between 20 and 60 m depth represents spall-related compaction of the shallow alluvium. Hints of low velocities are also present near the burial depth (∼364  m). The reflection seismic data show a prominent subhorizontal reflector at ∼300  m depth, a short-curved reflector at ∼200  m, and a high-amplitude reflector at ∼50  m depth. Comparisons of the reflection sections to synthetic data and borehole stratigraphy suggest that these features correspond to the alluvium–tuff contact, the partial collapse cavity, and the spalled layer, respectively.

Working conditions and the formation of health risks among workers of the petrochemical industry engaged in the production of methanol and its derivatives

2019 ◽  
pp. 266-271
Author(s):  
Nina M. Meshchakova ◽  
Marina P. Dyakovich ◽  
Salim F. Shayakhmetov
Keyword(s):  
Working Conditions ◽  
Health Risks ◽  
Quantitative Assessment ◽  
Circulatory System ◽  
Medical Examination ◽  
Physical Factors ◽  
Labor Intensity ◽  
Industrial Noise ◽  
Harmful Substances ◽  
The Impact

Introduction.Methanol and its derivatives occupy one of the leading places among the main organic synthesis intermediates in terms of their importance and scale of production. According to experts, by 2027 the global demand for methanol can reach 135 million tons, the annual growth will be about 5.5%. However, there is little information regarding the assessment of working conditions and occupational risks for workers in modern methanol production and its derivatives.The aim of the studyis hygienic assessment of working conditions and the formation of health risks in workers of modern production of methanol and methylamines.Materials and methods.The assessment of the main adverse factors of production is given. When studying the state of health, objective indicators (the results of an in-depth medical examination) and subjective (the results of a quantitative assessment of the risks of the main pathological syndromes associated with health) are considered.Results.According to long-term observations, the concentration of harmful substances in the air of the working area, indicators of labor severity, parameters of physical factors met hygienic requirements, with the exception of industrial noise exceeding the maximum permissible level, as well as labor intensity of 1 degree. The General assessment of working conditions corresponds to the category of harmful 2 degrees (3.2). According to the results of the medical examination and quantitative assessment of the risks of health disorders in workers, the most significant were functional disorders and diseases of the circulatory system. The levels of somatic pathology on the part of the main body systems were significantly higher in apparatchiks compared to the engineering and technical personnel (ETP).Conclusions:In the production of methyl alcohol and methylamines, the main hygienic importance is the impact on workers of the complex of harmful substances of 1-IV hazard classes in low concentrations, increased levels of industrial noise, labor intensity of 1 degree. According to the subjective assessment of health and medical examination, the greatest prevalence of health risks in workers was observed from the circulatory system, and the levels of the revealed somatic pathology were statistically significantly higher in apparatchiks compared with the ETP.

Geologic effects of the Rainier underground nuclear explosion : a summary progress report of U.S. Geological Survey investigations

1959 ◽  
Author(s):  
William H. Diment ◽  
V.R. Wilmarth ◽  
R.E. Wilcox ◽  
Alfred Clebsch ◽  
G.E. Manger ◽  
...  
Keyword(s):  
Nuclear Explosion ◽  
Progress Report ◽  
Geological Survey ◽  
Underground Nuclear Explosion

scholarly journals 1414. #Vaccine Twitter Influencers: is it Just About Reach and Followers?

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S714-S715
Author(s):  
Jean-Etienne Poirrier ◽  
Theodore Caputi ◽  
John Ayers ◽  
Mark Dredze ◽  
Sara Poston ◽  
...  
Keyword(s):  
United States ◽  
Social Media ◽  
Standard Deviation ◽  
Small Proportion ◽  
The United States ◽  
Research Support ◽  
Policy Makers ◽  
Media Messages ◽  
Social Media Platforms ◽  
The Impact

Abstract Background A small number of powerful users (“influencers”) dominates conversations on social media platforms: less than 1% of Twitter accounts have at least 3,000 followers and even fewer have hundreds of thousands or millions of followers. Beyond simple metrics (number of tweets, retweets...) little is known about these “influencers”, particularly in relation to their role in shaping online narratives about vaccines. Our goal was to describe influential Twitter accounts that are driving conversations about vaccines and present new metrics of influence. Methods Using publicly-available data from Twitter, we selected posts from 1-Jan-2016 to 31-Dec-2018 and extracted the top 5% of accounts tweeting about vaccines with the most followers. Using automated classifiers, we determined the location of these accounts, and grouped them into those that primarily tweet pro- versus anti-vaccine content. We further characterized the demographics of these influencer accounts. Results From 25,381 vaccine-related tweets available in our sample representing 10,607 users, 530 accounts represented the top 5% by number of followers. These accounts had on average 1,608,637 followers (standard deviation=5,063,421) and 340,390 median followers. Among the accounts for which sentiment was successfully estimated by the classifier, 10.4% (n=55) posted anti-vaccine content and 33.6% (n=178) posted pro-vaccine content. Of the 55 anti-vaccine accounts, 50% (n=18) of the accounts for which location was successfully determined were from the United States. Of the 178 pro-vaccine accounts, 42.5% (n=54) were from the United States. Conclusion This study showed that only a small proportion of Twitter accounts (A) post about vaccines and (B) have a high follower count and post anti-vaccine content. Further analysis of these users may help researchers and policy makers better understand how to amplify the impact of pro-vaccine social media messages. Disclosures Jean-Etienne Poirrier, PhD, MBA, The GSK group of companies (Employee, Shareholder) Theodore Caputi, PhD, Good Analytics Inc. (Consultant) John Ayers, PhD, GSK (Grant/Research Support) Mark Dredze, PhD, Bloomberg LP (Consultant)Good Analytics (Consultant) Sara Poston, PharmD, The GlaxoSmithKline group of companies (Employee, Shareholder) Cosmina Hogea, PhD, GlaxoSmithKline (Employee, Shareholder)

100 Years of Paper Seismograms from Denmark and Greenland, 1907–2008

2022 ◽  
Author(s):  
Trine Dahl-Jensen ◽  
Lif Lund Jacobsen ◽  
Ann-Sophie Graulund Sølund ◽  
Tine B. Larsen ◽  
Peter H. Voss
Keyword(s):  
World Wide ◽  
Nuclear Explosion ◽  
Historical Context ◽  
Nuclear Test ◽  
Novaya Zemlya ◽  
National Archives ◽  
Local Earthquake ◽  
Seismographic Network ◽  
Case Stories

Abstract The paper seismograms from 100 years of observations in Denmark and Greenland has since October 2021 been made available through the Danish National Archives. Five case stories illustrate the quality and variation of the seismograms, and the historical context of operation of the stations. (1) The earliest recorded earthquake in the archive is recorded at GDH station in Greenland, where the 1907 Mw 7.2 earthquake in Tajikistan is recorded on smoked paper. (2) The first Danish earthquake is a local event close to Copenhagen in 1930. (3) We have illustrated the 50 megaton nuclear explosion in Novaya Zemlya in 1961—the largest nuclear test explosion ever. (4) The M 9.2 earthquake in Alaska in 1964 recorded on several instruments at COP. (5) A local earthquake in northeast Greenland recorded both on paper on World-Wide Standard Seismographic Network instruments and digitally on a modern broadband instrument.

Radioecological studies at the Kraton-3 underground nuclear explosion site in 1978–2007: a review

2009 ◽  
Vol 100 (12) ◽  
pp. 1092-1099 ◽  
Author(s):  
V. Ramzaev ◽  
A. Mishin ◽  
V. Golikov ◽  
T. Argunova ◽  
V. Ushnitski ◽  
...  
Keyword(s):  
Nuclear Explosion ◽  
Underground Nuclear Explosion
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