Finite-frequency effects for imaging underground cavities

2021 ◽  
Author(s):  
Felix M. Schneider ◽  
Petr Kolínský ◽  
Götz Bokelmann
Keyword(s):  
Analytical Approach ◽  
Nuclear Test ◽  
Underground Cavity ◽  
Finite Frequency ◽  
Cavity Detection ◽  
Frequency Effects ◽  
The Past ◽  
Nuclear Tests ◽  
Seismic Anomalies ◽  
Test Ban

<p>We study finite-frequency effects that arise in cavity detection. The task comes along with the Onsite-Inspection part for the Comprehensive Nuclear Test Ban Treaty (CTBT), where the remnants of a potential nuclear test need to be identified. In such nuclear tests, there is preexisting knowledge about the depths at which nuclear tests may take place, and also about sizes that such cavities can attain. The task of cavity detection has consistently been a difficult one in the past, which is surprising, since a cavity represents one of the strongest seismic anomalies one can ever have in the subsurface. A conclusion of this study is that considering finite-frequency effects are rather promising for cavity detection, and that it is worthwhile to take them into account. We utilize an analytical approach for the forward problem of the a seismic wave interacting with a underground cavity in order to develop an inversion routine that finds and detects an underground cavity utilizing the transmitted wave-field.</p><p> </p>

FOREWORD

Geophysics ◽  
1964 ◽  
Vol 29 (2) ◽  
pp. 151-153 ◽  
Author(s):  
Charles C. Bates
Keyword(s):  
Prime Minister ◽  
State Of The Art ◽  
The United States ◽  
The Political ◽  
Bad Faith ◽  
Political Leaders ◽  
The Past ◽  
Current State ◽  
Nuclear Tests ◽  
Test Ban

A decade ago, it would have been the rare geophysicist indeed who would have predicted that his specialty was destined to become a major topic of discussion between such world political leaders as Presidents Eisenhower and Kennedy, Prime Minister Macmillan of Great Britain, and Chairman Khrushchev of the USSR. Yet this has come to pass during the past six years, for in 1958 there started the continuing round of international negotiations directed towards the creation of an effective underground test-ban treaty. During the conduct of these negotiations, it has been repeatedly necessary to assess the current state-of-the-art in seismology and its sister geophysical sciences, for the only detectable signals known to propagate for several hundreds to thousands of miles from underground nuclear tests are seismic in nature. With the United States policy being only to seek an underground-test-ban agreement incorporating strong safeguards against acts of bad faith, it is important that the political safe-guards be backed up by those of a geophysical nature.

Negotiations on Arms Control: Is There a Future?

2020 ◽  
Vol 25 (1) ◽  
pp. 53-68
Author(s):  
P. Terrence Hopmann
Keyword(s):  
Arms Control ◽  
Nuclear Test ◽  
Sufficient Condition ◽  
Arms Races ◽  
The Past ◽  
Cooperative Security ◽  
National Leaders ◽  
Relative Gains ◽  
Test Ban ◽  
Control Regime

Abstract The global arms control regime that began with the Partial Nuclear Test Ban Treaty (1963) appears to be collapsing rapidly, with many agreements now abandoned or barely enforced. This article analyzes some of the challenges to new negotiations on arms control based on developments in negotiation theory over the past 60 years. It focuses on the management of multilateral rather than bilateral negotiations, the need to focus on absolute rather than relative gains, the use of problem-solving techniques rather than traditional bargaining, the management of domestic opposition to arms control, the need for national leaders to become active proponents of new negotiations, and the need to focus on norms of cooperative security rather than engaging in arms races. It concludes that a necessary, if not sufficient, condition to save and rebuild the arms control regime is the adoption of more constructive approaches to negotiation on these vital issues.

Narrative conventions: What contribute to competitive prime time television News Discussions?

Think India ◽  
2019 ◽  
Vol 22 (3) ◽  
pp. 1758-1769
Author(s):  
Vidisha Madonna D’Souza
Keyword(s):  
Public Opinion ◽  
Analytical Approach ◽  
Research Study ◽  
Television News ◽  
Prime Time ◽  
Competitive Strategies ◽  
Indian English ◽  
The Past ◽  
One Stop ◽  
Narrative Conventions

Television News has been a resorted platform for Indian viewers over the past decades. A majority of Indian viewers are known to trust this platform for its highly expected one-stop, credible, professionally opinionated sense of reporting.  News channels have become platforms for celebrity journalists and anchors to exercise their authority. News organisations have become backbones of information and public opinion and journalists and their organisational agenda have taken this forward.  With bold and competitive strategies used to enable news presentations, it is essential to examine and recognize existing Television news narrative conventions and practices that have gained momentum in recent years. Through a qualitative analytical approach taken for this research study, it is clear that narrative conventions exist and modify, thus producing fashionable and modernized forms of presentation techniques during prime time. With a clear organisational norm and genre of discourse shared by Indian English television channels today, the paper highlights persisting organisational norms, unconventional discourses, rhetoric (audio and visual) and music – a contributing element as existing contributors of narrative conventions. 

Nuclear Powers' Disarmament Obligation under the Treaty on the Non-Proliferation of Nuclear Weapons and the Comprehensive Nuclear Test Ban Treaty: Interactions between Soft Law and Hard Law

2013 ◽  
Vol 27 (1) ◽  
pp. 169-188 ◽  
Author(s):  
ALESSANDRA PIETROBON
Keyword(s):  
Nuclear Weapons ◽  
Nuclear Test ◽  
Good Faith ◽  
Soft Law ◽  
Legal Obligation ◽  
Hard Law ◽  
The Us ◽  
Test Ban ◽  
Nuclear Test Ban ◽  
Test Ban Treaty

AbstractThe Comprehensive Nuclear Test Ban Treaty (CTBT) will not be effective until all the 44 states listed in its Annex 2 ratify it. A special link has been established between the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) and the CTBT. The disarmament obligation set by Article VI of the NPT, which has not yet been complied with, remains highly controversial. The relevant subsequent practice of the states parties to the NPT shows that the ratification of the CTBT is to be considered the first of the practical steps towards compliance with Article VI. However, as the practical steps do not set any legally binding norms, there is no legal obligation to ratify the CTBT, not even for the 44 states listed in Annex 2 whose ratification is essential. The paper deals with the position of nuclear powers party to the NPT that have not yet ratified the CTBT (most prominently the US and China) and demonstrates that these states should at least provide detailed motivation for their conduct. Otherwise, other states parties to the NPT could consider them as not complying in good faith with Article VI of the NPT and invoke the inadimplenti non est ademplendum rule to justify breaches of their own obligations under the same treaty.

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