Effects of shock‐induced tensile failure on mb‐Ms discrimination: Contrasts between historic nuclear explosions and the North Korean test of 9 October 2006

Patton, Howard J.; Taylor, Steven R.

doi:10.1029/2008gl034211

Cited by 42 publications

(43 citation statements)

References 18 publications

(18 reference statements)

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“… Patton and Taylor [2008, hereafter PT08] proposed a damage model for shock‐induced, deep‐seated tensile failure that identified extensional deformations along a vertical axis of symmetry and contractions around the waist of the explosion as a cause of damage. Such deformations can be seen in the hydrodynamic flow in frames 5–7 in Figure 1.…”

Section: An Explosion Source Model Accounting For Source Medium Damagementioning

confidence: 99%

The apparent explosion moment: Inferences of volumetric moment due to source medium damage by underground nuclear explosions

Patton

Taylor

2011

J. Geophys. Res.

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[1] Classical explosion source theory relates isotropic seismic moment to the steady state level of the reduced displacement potential. The theoretical isotropic moment for an incompressible source region M t is proportional to cavity volume V c created by pressurization of materials around the point of energy release. Source medium damage due to nonlinear deformations caused by the explosion will also induce volume change V d and radiate seismic waves as volumetric, double-couple, and compensated linear vector dipole (CLVD) body force systems. A new source model is presented where K is a relative measure of moment M CLVD with respect to the net moment from volumetric sources V c and V d . K values from moment tensor inversions steadily decrease from ∼2.5 at lower yields to ∼1.0 for the highest-yield shots on Pahute Mesa. A value of 1.0 implies M CLVD = 0 and, by inference, small V d . We hypothesize that the extent to which damage adds (or subtracts) volumetric moment is controlled by material properties and dynamics of stress wave rebound, shock wave interactions with the free surface, gravitational unloading, and slapdown of spalled near-surface layers. This hypothesis is tested by comparing measurements of isotropic momentM I with estimates of M t based on V c scaling relationships and velocity-density models. The results support the hypothesis and the conclusion thatM I represents the "apparent explosion moment" since it has contributions from direct effects due to cavity formation and indirect effects due to material damage. Implications for yield estimation usingM I are discussed in general and for the North Korean tests.Citation: Patton, H. J., and S. R. Taylor (2011), The apparent explosion moment: Inferences of volumetric moment due to source medium damage by underground nuclear explosions,

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Section: An Explosion Source Model Accounting For Source Medium Damagementioning

confidence: 99%

The apparent explosion moment: Inferences of volumetric moment due to source medium damage by underground nuclear explosions

Patton

Taylor

2011

J. Geophys. Res.

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“…Long‐period surface waves from the 2006 explosion were larger than expected for an explosion of such low yield. Patton and Taylor [2008] suggested that the high surface wave magnitude, M S , for the 2006 explosion could have resulted from stronger Rayleigh wave radiation due to the absence of spall (tensile failure) at depth as a consequence of the test being conducted in strong material such as granite. Bonner et al [2008] demonstrated that the 2006 event is not clearly screened from earthquakes with the M S : m b (surface wave to body wave magnitude) discriminant and also showed that accounting for the strong (high wave speed) emplacement conditions brings the yield estimated from M S closer to that inferred from m b .…”

Section: The 2006 and 2009 Dprk Nuclear Testsmentioning

confidence: 99%

Simulation of topographic effects on seismic waves from shallow explosions near the North Korean nuclear test site with emphasis on shear wave generation

Rodgers¹,

Petersson²,

Sjögreen³

2010

J. Geophys. Res.

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[1] We performed high-resolution (8 Hz) three-dimensional simulations of ground motions from shallow explosions in the presence of rough surface topography near the North Korean nuclear test site to study elastic propagation effects with emphasis on theoretical aspects of shear wave generation. Interaction with rough topography causes significant P-to-Rg scattering along the surface with amplification of high-frequency (2-8 Hz) shear waves relative to the flat Earth case. Shear waves of different polarizations are coupled by topographic scattering. Rg precursors composed of P-to-Rg conversions traveling as surface waves have the spectral amplitudes comparable to the P wave, while the Rg phase has the low-frequency (0.5-3 Hz) spectral shape of the Rg from the flat case plus the high-frequency (3-8 Hz) P wave spectra. Motions at near-vertical takeoff angles corresponding to teleseismic propagation are increased or decreased indicating that waves are focused or defocused by topographic features above the source. Topographic roughness has a dramatic effect as short-wavelength features (<2-5 km) are included. Higher frequencies are amplified by topography, including frequencies corresponding to wavelengths shorter than the shortest topographic scale length. Overall topography enhances energy propagating along the surface near the source, amplifies surface waves, and tends to balance SV-and SH-polarized motions, all of which impact shear wave observations used for nuclear explosion monitoring. Further simulation studies could elucidate how the wavefield emerging from a topographically rough area ultimately propagates to regional and/or teleseismic distances.Citation: Rodgers, A. J., N. A. Petersson, and B. Sjogreen (2010), Simulation of topographic effects on seismic waves from shallow explosions near the North Korean nuclear test site with emphasis on shear wave generation,

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“…However, in a number of studies (KIM and RICHARDS, 2007;KVAERNA et al, 2007;KOPER et al, 2007;ZHAO et al, 2008) using high-frequency spectral ratios of regional P-and S-wave signals that were archived from previous small earthquakes, the event of October 9, 2006, was identified as an explosion with very high confidence. PATTON and TAYLOR (2008) present an explosion model where tensile failure of surface layers is completely suppressed to explain the poor performance of the teleseismic m b -M s discriminant for the North Korean test. In order to check the IDC and USGS localization, which was mainly based on teleseismic data, waveform data of stations in the regional distance range were examined for onsets of regional seismic waves.…”

Section: Detection Identification Locationmentioning

confidence: 99%

Satellite Earth Observations Support CTBT Monitoring: A Case Study of the Nuclear Test in North Korea of Oct. 9, 2006 and Comparison with Seismic Results

Schlittenhardt

Canty

Grünberg

2010

Pure Appl. Geophys.

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The Comprehensive Nuclear-Test-Ban Treaty prescribes the use of seismic stations and arrays as the main measure for verification of Treaty compliance. Since the inception of the Treaty, a vast amount of open source earth observation satellite data has become available. This paper investigates the potential for combining seismic and satellite data for more effective monitoring and response. With data acquired before, during and after the alleged North Korean underground nuclear test on October 9, 2006, wide area change detection techniques using medium resolution optical/infrared satellite sensors are combined with localized highresolution imagery to attempt to pinpoint the test location within the area identified by the seismic measurements. Problems associated with the timeliness, degree of coverage and ambiguity of the remote sensing data are pointed out, however it is generally concluded that their integration into the CTBT regime would valuably complement the existing seismic observation network.

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Effects of shock‐induced tensile failure on m_b‐M_s discrimination: Contrasts between historic nuclear explosions and the North Korean test of 9 October 2006

Cited by 42 publications

References 18 publications

The apparent explosion moment: Inferences of volumetric moment due to source medium damage by underground nuclear explosions

The apparent explosion moment: Inferences of volumetric moment due to source medium damage by underground nuclear explosions

Simulation of topographic effects on seismic waves from shallow explosions near the North Korean nuclear test site with emphasis on shear wave generation

Satellite Earth Observations Support CTBT Monitoring: A Case Study of the Nuclear Test in North Korea of Oct. 9, 2006 and Comparison with Seismic Results

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