CTBTO Research Papers - Academia.edu (original) (raw)

Stopping nuclear proliferation is at the top of the international agenda for years. With 182 signatures and 153 ratifications most states recognize the Comprehensive Test Ban Treaty as substantially inhibiting further vertical nuclear... more

Stopping nuclear proliferation is at the top of the international agenda for years. With 182 signatures and 153 ratifications most states recognize the Comprehensive Test Ban Treaty as substantially inhibiting further vertical nuclear proliferation and in some extend halting the horizontal spread of nuclear weapons. Unfortunately, the entry into force of the treaty is in limbo due to nine hold-out states - China, Egypt, India, Indonesia, Iran, Israel, North Korea, Pakistan and the United States. Why do they oppose it? Are there any windows of opportunity for the CTBT? The qualitative analysis distinguishes the inter-state, intra-state and decision-maker-level arguments. It is conducted in form of nine case studies and is primarily based upon official documents. Governmental statements rarely reveal full reasons for states’ reluctance concerning the CTBT, but outline necessary conditions for its success and provide a framework to work out policy approaches aiming at the treaties entry into force. The study points at a complex interrelation of technical reasons, security related arguments, arms-control related motivations and domestic policy issues. The most important findings to grapple with are seeking regionally comprehensive solutions and closing all outstanding loopholes accompanying the treaty.

The International Data Centre (IDC) in Vienna,Austria, is determining, as part of automatic processing, sensornoise levels for all seismic, hydroacoustic, and infrasound (SHI)stations in the International Monitoring System (IMS)... more

The International Data Centre (IDC) in Vienna,Austria, is determining, as part of automatic processing, sensornoise levels for all seismic, hydroacoustic, and infrasound (SHI)stations in the International Monitoring System (IMS) operated bythe Provisional Technical Secretariat of the ComprehensiveNuclear-Test-Ban Treaty Organization (CTBTO). Sensor noise isbeing determined several times per day as a power spectral density(PSD) using the Welch overlapping method. Based on accumulatedPSD statistics a probability density function (PDF) is also deter-mined, from which low and high noise curves for each sensor areextracted. Global low and high noise curves as a function of fre-quency for each of the SHI technologies are determined as theminimum and maximum of the individual station low and highnoise curves, respectively, taken over the entire network of con-tributing stations. An attempt is made to ensure that only correctlycalibrated station data contributes to the global noise models byadditionally considering various automatic detection statistics. Inthis paper global low and high noise curves for 2010 are presentedfor each of the SHI monitoring technologies. Except for a veryslight deviation at the microseism peak, the seismic global lownoise model returns identically the P
ETERSON
(1993) NLNM lownoise curve. The global infrasonic low noise model is found toagree with that of B
OWMAN
et al.
(2005,2007) but disagrees with the revised results presented in B
OWMAN
et al.
(2009) by a factor of 2 in the calculation of the PSD. The global hydroacoustic low andhigh noise curves are found to be in quantitative agreement withUrick’s oceanic ambient noise curves for light to heavy shipping.Whale noise is found to be a feature of the hydroacoustic high noisecurves at around 15 and 25 Hz.

Understanding radioxenon time series and being able to distinguish anthropogenic from nuclear explosion signals are fundamental issues for the technical verification of the Comprehensive Nuclear-Test-Ban Treaty. Every radioxenon event... more

Understanding radioxenon time series and being able to distinguish anthropogenic from nuclear explosion signals are fundamental issues for the technical verification of the Comprehensive Nuclear-Test-Ban Treaty. Every radioxenon event categorisation methodology must take into account the background at each monitoring site to uncover anomalies that may be related to nuclear explosions. Feedback induced by local meteorological patterns on the equipment and on the sampling procedures has been included in the analysis to improve a possible event categorisation scheme. The occurrence probability of radioxenon outliers has been estimated with a time series approach characterising and avoiding the influence of local meteorological patterns. A power spectrum estimator for radioxenon and meteorological time series was selected; the randomness of the radioxenon residual time series has been tested for white noise by Kolmogorov–Smirnov and Ljung–Box tests. This methodological approach was applied to radioxenon data collected at two monitoring sites located at St. John’s, Canada and Charlottesville, USA, equipped with two different noble gas systems. It shows different feedback with local meteorological patterns and randomness for the radioxenon data recorded at the selected sites of St. John’s and Charlottesville as well as a different occurrence probability of the outliers in the normalized radioxenon original and residual time series.

In late 2016, we conducted the first nationally representative survey in several years on U.S. public attitudes toward the CTBT and nuclear testing. We then asked survey respondents about the motivations underlying their expressed... more

In late 2016, we conducted the first nationally representative survey in several years on U.S. public attitudes toward the CTBT and nuclear testing. We then asked survey respondents about the motivations underlying their expressed positions. Overall, the data revealed widespread support for the test ban across all demographic subgroups in the United States. A total of 65 percent of all respondents supported the Senate giving its advice and consent to CTBT ratification, while 15.3 percent opposed this measure. A further 19.7 percent remained undecided. Among political subgroups: 69.8 percent of Democrats, 56.2 percent of Republicans, and 66.3 percent of Independent supported ratification.

A spatial filter is often attached to a microphone or microbarometer in order to reduce the noise caused by atmospheric turbulence. This filtering technique is based on the assumption that the coherence length of turbulence is smaller... more

A spatial filter is often attached to a microphone or
microbarometer in order to reduce the noise caused by atmospheric
turbulence. This filtering technique is based on the assumption that
the coherence length of turbulence is smaller than the spatial extent
of the filter, and so contributions from turbulence recorded at
widely separated ports will tend to cancel while those of the signal
of interest, which will have coherence length larger than the spatial
dimensions of the filter, will be reinforced. In this paper, the plane
wave response for a spatial filter with an arbitrary arrangement of
open ports is determined. It is found that propagation over different
port-to-sensor distances causes out-of-phase sinusoids to be sum-
med at the central manifold and can lead to significant amplitude
decay and phase delays as a function of frequency. The determined
spatial filter plane wave response is superimposed on an array
response typical of infrasound arrays that constitute the Interna-
tional Monitoring System infrasound network used for nuclear
monitoring purposes. It is found that signal detection capability in
terms of the Fisher Statistic can be significantly degraded at certain
frequencies. The least-squares estimate of signal slowness can
change by up to 1.5° and up to 10 m/s if an asymmetric arrange-
ment of low and high frequency spatial filters is used. However, if a
symmetric arrangement of filters is used the least-squares estimate
of signal slowness is found to be largely unaffected, except near the
predicted null frequency.

Just over two decades since the Comprehensive Test Ban Treaty (CTBT) opened for signature, a total of 183 states have signed and 166 have ratified the accord. However, the treaty cannot enter into force until all 44 “nuclear-capable”... more

Just over two decades since the Comprehensive Test Ban Treaty (CTBT) opened for signature, a total of 183 states have signed and 166 have ratified the accord. However, the treaty cannot enter into force until all 44 “nuclear-capable” states listed in its Annex 2 deposit their instruments of ratification. Eight of these states have not ratified the test ban. In light of this situation, it is nearly second nature for academic and policy discussions of the CTBT to overwhelmingly focus on the political roadblocks obstructing its entry into force. By contrast, this paper contends that the politics of treaty ratification are not the only dimension to the test ban discussion. Instead, it highlights a series of overlooked or understudied aspects of nuclear explosion monitoring. States can undertake a number of scientific and technical initiatives to strengthen CTBT monitoring, even in the absence of entry into force. In turn, by engaging in these types of projects, states do not merely create a more difficult climate for evasive nuclear testing; they may also bolster long-term prospects for the treaty’s ratification. This roadmap lays out a number of complementary efforts that policymakers may pursue toward this end.

This article discusses a series of scientific and technical initiatives that the incoming Trump administration should take to enhance international nuclear explosion monitoring capabilities. Further, the article suggests that these types... more

This article discusses a series of scientific and technical initiatives that the incoming Trump administration should take to enhance international nuclear explosion monitoring capabilities. Further, the article suggests that these types of advancements to the Comprehensive Nuclear-Test-Ban Treaty (CTBT) monitoring and verification regime might stimulate global, bottom-up pressures for treaty ratification and entry into force.

India’s tryst with global nuclear regimes unswerving or chequered is a matter of protracted debate. While many Western scholars point to India’s defiant behaviour, Indian scholars trumpet New Delhi’s unambiguous non-proliferation record... more

India’s tryst with global nuclear regimes unswerving or chequered is a matter of protracted debate. While many Western scholars point to India’s defiant behaviour, Indian scholars trumpet New Delhi’s unambiguous non-proliferation record and disarmament pledge. Amidst this dyadic narrative, India manoeuvres to be an insider of the global non-proliferation, arms control and disarmament regimes. How quick and what value it would add to these regimes as member is a matter of conjecture; but its rendezvous with the global nuclear regimes would turn a full circle the day it would gate-crash the hitherto developed countries’ privileged nuclear cohorts.

Forthcoming conference participation.

The Centro di Ricerche Sismologiche (CRS, Seismological Research Center) in Udine (Italy) of the OGS (Istituto Nazionale di Oceanografia e di Geofisica Sperimentale), the Italian National Institute for Oceanography and Experimental... more

The Centro di Ricerche Sismologiche (CRS, Seismological Research Center) in Udine (Italy) of the OGS (Istituto Nazionale di Oceanografia e di Geofisica Sperimentale), the Italian National Institute for Oceanography and Experimental Geophysics, after the M=6.4 earthquake occurred in 1976 in the Friuli-Venezia Giulia region, started to operate the Northeastern Italy Seismic Network: it currently consists of 18 very sensitive broad band and 20 simpler short period seismic stations, all telemetered to and acquired in real time at the OGS-CRS data center. OGS is formally part of the Central and Eastern European Earthquake Research Network CE3RN (http://www.CE3RN.eu/; Bragato et al., 2014). Real time data exchange agreements in place with CE3RN and other Italian and Swiss seismological institutes lead to a total number of about 100 seismic stations acquired in real time by the CRS, which makes the OGS the reference institute for seismic monitoring of Northeastern Italy (Bragato et al., 2011).
To further support CTBTO activities (Pesaresi and Horn, 2004), OGS proposes with the support of the Italian CTBTO National Authority one of its stations of the Northeast Italy Seismic Network as a Cooperating National Facility (CNF) to the CTBTO. A description of the Cludinico (CLUD) station proposed as CNF, together with results of CTBTO monitoring improvements simulations will be here illustrated.

ABSTRACT The year 2016 marked twenty years since the Comprehensive Nuclear-Test-Ban Treaty (CTBT) opened for signature; the twenty-fifth anniversary of the US nuclear-testing moratorium occurred the following year. The international... more

ABSTRACT The year 2016 marked twenty years since the Comprehensive Nuclear-Test-Ban Treaty (CTBT) opened for signature; the twenty-fifth anniversary of the US nuclear-testing moratorium occurred the following year. The international political climate, nuclear-explosion-monitoring capabilities, and US stockpile stewardship have all changed drastically since the US Senate voted against CTBT ratification in 1999, and they continue to evolve. Yet the most recent public-opinion survey on the test ban, showing 84 percent approval across the United States, dates to 2012. Do Americans still emphatically support the CTBT? To answer this question, we worked with the research firm YouGov to design and implement a new scientific survey assessing the current state of national opinion toward the test ban. Analyzing the survey results shows that, although US public support for the test ban remains strong, it has probably weakened since 2012. While political party identification is the best predictor of treaty support or opposition, a majority of Democrats, Republicans, and independents support ratification. However, many Americans remain undecided on whether the Senate should provide its “advice and consent” to ratification.

This article discusses the potential utility of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) as a litmus test of North Korean Supreme Leader Kim Jong-un's actual interest in nuclear disarmament. Now that the public show of the... more

This article discusses the potential utility of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) as a litmus test of North Korean Supreme Leader Kim Jong-un's actual interest in nuclear disarmament. Now that the public show of the Singapore Summit with U.S. President Donald Trump is over, the difficult work toward nuclear disarmament begins. The most promising near-term option to build U.S.-North Korean confidence and make meaningful progress toward nuclear disarmament is to obtain Pyongyang’s signature on and ratification of the CTBT. If Kim is serious about turning back the clock on his nuclear program, permanent cessation of nuclear testing should be mutually agreeable. The treaty would restrict North Korean nuclear weapons development and lock the regime into arms control commitments. Further, it would open the door for representatives of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) to verify the recently declared closure of the nuclear test site at Punggye-ri.

Policy analyses of underground test monitoring in support of the Comprehensive Nuclear Test Ban Treaty (CTBT) usually focus on the Primary and Auxiliary Seismological Networks of the International Monitoring System (IMS). In addition to... more

Policy analyses of underground test monitoring in support of the Comprehensive Nuclear Test Ban Treaty (CTBT) usually focus on the Primary and Auxiliary Seismological Networks of the International Monitoring System (IMS). In addition to overlooking National Technical Means (NTM), this lens fails to consider thousands of seismic stations and arrays operated by government agencies, universities , and research institutes. These networks serve important functions in earthquake hazard mitigation, tsunami warning systems, and civilian and military disaster responses, but they can also detect waveform data from suspected nuclear tests. This paper explores mechanisms for seismic data sharing in the scientific community and evaluates their potential contributions to CTBT monitoring. It concludes that seismology is the first line of sight for monitoring underground nuclear tests, and scientific data sharing and capacity building can help to detect and deter noncompliance with the CTBT.

ABSTRACT The year 2016 marked twenty years since the Comprehensive Nuclear-Test-Ban Treaty (CTBT) opened for signature; the twenty-fifth anniversary of the US nuclear-testing moratorium occurred the following year. The international... more

ABSTRACT The year 2016 marked twenty years since the Comprehensive Nuclear-Test-Ban Treaty (CTBT) opened for signature; the twenty-fifth anniversary of the US nuclear-testing moratorium occurred the following year. The international political climate, nuclear-explosion-monitoring capabilities, and US stockpile stewardship have all changed drastically since the US Senate voted against CTBT ratification in 1999, and they continue to evolve. Yet the most recent public-opinion survey on the test ban, showing 84 percent approval across the United States, dates to 2012. Do Americans still emphatically support the CTBT? To answer this question, we worked with the research firm YouGov to design and implement a new scientific survey assessing the current state of national opinion toward the test ban. Analyzing the survey results shows that, although US public support for the test ban remains strong, it has probably weakened since 2012. While political party identification is the best predictor of treaty support or opposition, a majority of Democrats, Republicans, and independents support ratification. However, many Americans remain undecided on whether the Senate should provide its “advice and consent” to ratification.

Declared North Korean nuclear tests in 2006, 2009, 2013, and 2016 were observed seismically at regional and teleseismic distances. Waveform similarity allows the events to be located relatively with far greater accuracy than the absolute... more

Declared North Korean nuclear tests in 2006, 2009, 2013, and 2016 were observed seismically at regional and teleseismic distances. Waveform similarity allows the events to be located relatively with far greater accuracy than the absolute locations can be determined from seismic data alone. There is now significant redundancy in the data given the large number of regional and teleseismic stations that have recorded multiple events, and relative location estimates can be confirmed independently by performing calculations on many mutually exclusive sets of measurements. Using a 1-dimensional global velocity model, the distances between the events estimated using teleseismic P phases are found to be approximately 25% shorter than the distances between events estimated using regional Pn phases. The 2009, 2013, and 2016 events all take place within 1 km of each other and the discrepancy between the regional and teleseismic relative location estimates is no more than about 150 m. The discrepancy is much more significant when estimating the location of the more distant 2006 event relative to the later explosions with regional and teleseismic estimates varying by many hundreds of meters. The relative location of the 2006 event is challenging given the smaller number of observing stations, the lower signal-to-noise ratio, and significant waveform dissimilarity at some regional stations. The 2006 event is however highly significant in constraining the absolute locations in the terrain at the Punggye-ri test-site in relation to observed surface infrastructure. For each seismic arrival used to estimate the relative locations, we define a slowness scaling factor which multiplies the gradient of seismic traveltime versus distance, evaluated at the source, relative to the applied 1-d velocity model. A procedure for estimating correction terms which reduce the double-difference time residual vector norms is presented together with a discussion of the associated uncertainty. The modified velocity gradients reduce the residuals, the relative location uncertainties, and the sensitivity to the combination of stations used. The traveltime gradients appear to be overestimated for the regional phases, and teleseismic relative location estimates are likely to be more accurate despite an apparent lower precision. Calibrations for regional phases are essential given that smaller magnitude events are likely not to be recorded teleseismically. We discuss the implications for the absolute event locations. Placing the 2006 event under a local maximum of overburden at 41.293°N, 129.105°E would imply a location of 41.299°N, 129.075°E for the January 2016 event, providing almost optimal overburden for the later four events.