Source Characterization of the Declared North Korean Nuclear Tests From Regional Distance Coda Wave Spectral Ratios

Delbridge, B. G.; Carmichael, Joshua D.; Phillips, W. S.; Cleveland, K. Michael; Begnaud, M. L.; Gammans, Christine

doi:10.1029/2022jb024728

Cited by 4 publications

(6 citation statements)

References 94 publications

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“…Alvizuri and Tape (2018) applied a Comparison of the results of yield estimates from different studies. Different symbols indicate North Korean nuclear tests NKT1-6, whereas different colors indicate different methods, including regional waveform envelopes (Pasyanos and Myers, 2018), seismic moments (Chiang et al, 2018;Pasyanos, 2022), waveform equalization to teleseismic P and regional Pn seismograms and high-frequency (>4.0 Hz) P waves (Voytan et al, 2019), coda spectral ratios (Delbridge et al, 2023), NEIC m b after burial depth correction (Yang et al, 2021), and m b (Lg) (Xie and Zhao, 2018). The gray shading represents 0.5 to 2 times the deviation range of the yield estimations obtained in this study.…”

Section: Lg-wave Source Spectramentioning

confidence: 99%

“…Our results are consistent with those obtained from previous teleseismic observations. KEYWORDS seismic attenuation, Lg source spectra, yield estimation, underground nuclear tests, the Korean Peninsula 10.3389/feart.2024.1386932 regional monitoring techniques for yield estimation (Hong et al, 2008;Zhao et al, 2008;Pasyanos et al, 2012;Yao et al, 2018;Kim et al, 2019;Ma et al, 2020;Delbridge et al, 2023). The continental crustal-guided Lg-wave is the most prominent phase of a seismic event at a regional distance (e.g., Hong et al, 2008).…”

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confidence: 99%

“…Historical explosive yield estimations are obtained by converting seismic magnitudes from the amplitudes of teleseismic body waves to yields using empirical relationships (Bowers et al, 2001;Nuttli, 1973;Nuttli, 1986;Patton and Schlittenhardt, 2005;Patton and Taylor, 2011). Since the North Korean nuclear test site is uncalibrated, there are challenges in terms of absolute explosion magnitude and yield estimations (Delbridge et al, 2023). As a measurable and wellunderstood physical parameter of seismic sources, the seismic moment allows us to move away from purely empirical calibrations and directly calculate the yield of explosions theoretically (Pasyanos and Chiang, 2021).…”

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confidence: 99%

“…Although the attenuation of low-frequency (<0.05 Hz) seismic waves may be relatively stable, the signal-to-noise ratio (SNR) for low-yield explosions is poor at relatively lower frequencies. Over a large frequency range, crustal seismic attenuation might introduce significant errors into seismic moment calculations (e.g., Delbridge et al, 2023). Delbridge et al (2023) calculated coda wave spectral ratios to remove path and site effects to solve precise relative source moments.…”

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confidence: 99%

“…Over a large frequency range, crustal seismic attenuation might introduce significant errors into seismic moment calculations (e.g., Delbridge et al, 2023). Delbridge et al (2023) calculated coda wave spectral ratios to remove path and site effects to solve precise relative source moments. Therefore, if a high-resolution seismic attenuation model is used to calculate the seismic moment, the reliability of the explosive yield estimation can be effectively improved.…”

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confidence: 99%

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Yield estimation of North Korean underground nuclear tests using Lg-wave source spectra

Lu,

Zhao,

Pang

et al. 2024

Front. Earth Sci.

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In seismic nuclear monitoring, attenuation models are important prerequisites for reliably estimating the explosive yield in an uncalibrated region without the occurrence of standard events. The seismic moment obtained by fitting source spectra is related to the source energy. This approach is appropriate for estimating yield, as the attenuation effects on the propagation path can be accurately considered. In this study, we collected 2022 vertical component waveforms in and around the Korean Peninsula from May 2010 to May 2022 to construct a high-resolution broadband Lg-wave attenuation model and inverted the Lg-wave source excitation spectra of the nuclear explosion simultaneously with attenuation correction. We obtained the scalar seismic moments by fitting the theoretical source spectra based on the Brune (J. Geophys. Res., 1970, 75, 4997–5009) model. Under the given emplacement conditions and burial depths, the seismic moments can be used to estimate yields of the North Korean nuclear tests, which are 4.6, 8.5, 19.9, 20.9, 24.7, and 337.4 kt for six nuclear explosions that occurred between 2006 and 2017. Our results are consistent with those obtained from previous teleseismic observations.

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Section: Lg-wave Source Spectramentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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confidence: 99%

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confidence: 99%

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Yield estimation of North Korean underground nuclear tests using Lg-wave source spectra

Lu,

Zhao,

Pang

et al. 2024

Front. Earth Sci.

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Generalization of Deep-Learning Models for Classification of Local Distance Earthquakes and Explosions across Various Geologic Settings

Maguire,

Schmandt,

Wang

et al. 2024

Seismological Research Letters

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Although accurately classifying signals from earthquakes and explosions at local distance (<250 km) remains an important task for seismic network operations, the growing volume of available seismic data presents a challenge for analysts using traditional source discrimination techniques. In recent years, deep-learning models have proven effective at discriminating between low-magnitude earthquakes and explosions measured at local distances, but it is not clear how well these models are capable of generalizing across different geological settings. To address the issue of generalization between regions, we train deep-learning models (convolutional neural networks [CNNs]) on time–frequency representations (scalograms) of three-component earthquake and explosion signals from eight different regions in the continental United States. We explore scenarios where models are trained on data from all regions, individual regions, or all but one region. We find that although CNN models trained on individual regions do not necessarily generalize well across different settings, models trained on multiple regions that include diverse path coverage generalize to new regions, with station-level accuracy of up to 90% or more for data sets from unseen regions. In general, CNN-based discrimination models significantly outperform models based on uncorrected P/S ratio (measured in the 10–18 Hz frequency band), even when CNN models are tested on data from entirely unseen regions.

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Probabilistic Programming for Transportable Source Characterization and Uncertainty Quantification of the North Korean Nuclear Tests 2006–2017

Alfaro-Diaz,

Kintner,

Scott Phillips

et al. 2024

Seismological Research Letters

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We introduce a transportable technique to determine the yield and depth of burial (DOB) from seismic source spectra of underground nuclear explosions. We demonstrate this technique on the six declared North Korean nuclear tests. This approach derives source spectra in absolute units from regional phase (Pg) amplitudes by correcting the observations for geometric spreading, attenuation, and site amplification. We couple the source spectra and explosion source models with a probabilistic programming framework that integrates deep learning techniques and Bayesian modeling. This approach permits the exchange of information across various data categories to quantify both the data and model uncertainty. This technique stands out as an innovative use of broad-area propagation models, making it transportable across various geologic settings. This method proves to be effective in scenarios with diverse and/or limited observational data, even when the source depth is unknown. We present new independent estimates of absolute yield and DOB that are consistent with the prior assessments, underscoring the potential of this method in enhancing transportable nuclear explosion monitoring capabilities.

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Source Characterization of the Declared North Korean Nuclear Tests From Regional Distance Coda Wave Spectral Ratios

Cited by 4 publications

References 94 publications

Yield estimation of North Korean underground nuclear tests using Lg-wave source spectra

Yield estimation of North Korean underground nuclear tests using Lg-wave source spectra

Generalization of Deep-Learning Models for Classification of Local Distance Earthquakes and Explosions across Various Geologic Settings

Probabilistic Programming for Transportable Source Characterization and Uncertainty Quantification of the North Korean Nuclear Tests 2006–2017

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