Improvements to regional explosion identification using attenuation models of the lithosphere

Pasyanos, Michael E.; Walter, William R.

doi:10.1029/2009gl038505

Cited by 20 publications

(10 citation statements)

References 21 publications

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“…These models have been primarily driven by the need in nuclear explosion monitoring to reduce the scatter of regional phase amplitudes for earthquakes, and to better separate the relative P/S amplitudes of explosions in the process (e.g. Pasyanos and Walter, 2009). Accounting for regional amplitude variations is also critical in calibrating magnitude formulas that rely on regional phases, such as Pn and Lg.…”

Section: Methodsmentioning

confidence: 99%

“…We make use of an attenuation model of the lithosphere in the Middle East (Pasyanos et al, 2009), which was developed from weak ground motions using the amplitudes of regional phases Pn, Pg, Sn, and Lg. Because this model covers apparent Qp and Qs of the crust and upper mantle, it can be used to estimate anelasticity for the primary local and regional phases.…”

Section: Examplementioning

confidence: 99%

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A Case for the Use of 3D Attenuation Models in Ground-Motion and Seismic-Hazard Assessment

Pasyanos

2011

Bulletin of the Seismological Society of America

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Attenuation relationships that are used to characterize estimated ground motion often ignore details of the earth's highly-variable three-dimensional velocity and attenuation structure. Increasingly available attenuation models can be used to refine the expected ground motions. First, some tests are performed to look at the effect of the variability in several parameters, such as crustal attenuation, upper mantle attenuation and crustal thickness. A concrete example is then provided using the results of a recent crust and upper mantle attenuation model of the Middle East. We find 30-40% variations in 1 Hz spectral accelerations simply from the variations of the same event recorded in different directions. Since overall regional variability is expected to be even higher, this effect seems significant enough to be accounted for in strong ground motion estimates and seismic hazard assessment. This has the potential to account for some of the smaller scale amplitude variations not considered using broadly applied 1-D attenuation relationships.

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Section: Methodsmentioning

confidence: 99%

Section: Examplementioning

confidence: 99%

A Case for the Use of 3D Attenuation Models in Ground-Motion and Seismic-Hazard Assessment

Pasyanos

2011

Bulletin of the Seismological Society of America

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“…In a series of papers, we have developed the methodology using the Lg phase (Pasyanos et al, 2009a), extended the method to use amplitudes of the Pn, Pg, Sn, and Lg in a multiphase inversion method (Pasyanos et al, 2009b), then used the model in a series of applications including seismic discrimination between earthquakes and explosions (Pasyanos and Walter, 2009;Pasyanos et al, 2012a), moment magnitude estimation (Pasyanos, 2010), and in strong ground motion predictions for seismic hazard (Pasyanos, 2011). In a further extension of the model, we used the attenuation model in the analysis of the yield and depth of the 2006 and 2009 DPRK nuclear tests (Pasyanos et al, 2012b).…”

Section: Introductionmentioning

confidence: 99%

A Lithospheric Attenuation Model of North America

Pasyanos¹

2013

Bulletin of the Seismological Society of America

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Recent moderate-sized, but strongly-felt, earthquakes in eastern and central North America have highlighted the important role of the earth's attenuation structure in estimating and predicting local and regional ground motions. Over the past several years, we have been developing methods to use the amplitudes of regional phases Pn, Pg, Sn, and Lg to invert for the crust and upper mantle attenuation structure in Eurasia, and have recently started transporting the methodology to North America. We now have path coverage for most of North America, including Canada, the United States, Mexico, and portions of the Caribbean, with the best coverage in the United States. After describing the development of the model, we will discuss the results in the context of the tectonics of the region, most notably the large differences between western North America and areas east of the Rockies. We will then demonstrate the use of the model in a number of applications including estimating reliable moment magnitudes for the Wells, NV earthquake sequence, the use of the models in strong ground motion prediction for the Mineral, VA mainshock, and in both discriminating and estimating explosion characteristics (depth, yield) of events at the Nevada Test Site.2

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“…In Figure 11, we argue for radiation pattern effects in high-frequency seismic energy which are commonly omitted for high-frequency analysis [Pasyanos and Walter, 2009]. Essentially, S n is an important observation in regional explosion identification where a weak S n implies an explosion source.…”

Section: Short-period Observationsmentioning

confidence: 95%

Lithospheric waveguide beneath the Midwestern United States; massive low-velocity zone in the lower crust

Chu

Helmberger

2014

Geochem. Geophys. Geosyst.

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Variations in seismic velocities are essential in developing a better understanding of continental plate tectonics. Fortunately, the USArray has provided an excellent set of regional phases from the recent M5.6 Oklahoma earthquake (6 November 2011, Table 1) that can be used for such studies. Its strike-slip mechanism produced an extraordinary set of tangential recordings extending to the northern edge of the USArray. The crossover of the crustal slow S to the faster S n phase is well observed. S m S has a critical distance of around 2 and its first multiple, SmS 2 , reaches critical angle near a distance of about 4 , and so on, until S m S n merges with the stronger crustal Love waves. These waveforms are modeled in the period band of 2-100 s by assuming a simple three-layer crust and a two-layer mantle, which allows a grid-search approach. Our results favor a 15 km thick low-velocity zone (LVZ) in the lower crust with an average shear velocity of less than 3.6 km/s. The short-period Lg waves (S waves, at periods of 0.5-2 s) travel with velocities near 3.5 km/s and decay with distance faster than high-frequency S n (>5.0 Hz) which travels at a velocity of 4.6 km/s and persists to large distances. Although these short-period waveforms are not modeled, their amplitude and travel times can be explained by adding a small velocity jump just below the Moho with essentially no attenuation. P n is equally strong but is complicated by the interference produced by the depth phase sP, but well modeled. The P velocities appear normal with no definitive LVZ. While these observations of S n and P n are common beneath most cratons, the lower crustal LVZ appears to be anomalous and maybe indicative of hydrous processes, possibly caused by the descending Farallon slab.

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Improvements to regional explosion identification using attenuation models of the lithosphere

Cited by 20 publications

References 21 publications

A Case for the Use of 3D Attenuation Models in Ground-Motion and Seismic-Hazard Assessment

A Case for the Use of 3D Attenuation Models in Ground-Motion and Seismic-Hazard Assessment

A Lithospheric Attenuation Model of North America

Lithospheric waveguide beneath the Midwestern United States; massive low-velocity zone in the lower crust

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