This paper combines the power of deep-learning with generalizability physics-based features, to present an advanced method for seismic discrimination between earthquakes and explosions. The proposed contains two branches: a deep learning branch operating directly on waveforms or spectrograms, second parametric features. These features are high-frequency P/S amplitude ratios difference local magnitude (ML) coda duration (MC). combination achieves better generalization performance when applied...

For seismic stations deployed on ice sheets, determining crustal structure using P wave receiver functions can be difficult since reverberations may mask P‐to‐S (Ps) conversions from the crust‐mantle boundary (Moho). In this study, we assess usefulness of S (SRFs), which are not affected by multiples, for investigating beneath sheets analyzing broadband data recorded across Transantarctic Mountains (TAMs) and East Antarctic (EA) craton. Clear S‐to‐P (Sp) Moho obtained standard SRF processing...

Research Article| March 19, 2019 Investigating the Effectiveness of P/S Amplitude Ratios for Local Distance Event Discrimination Moira L. Pyle; Pyle Corresponding Author aLawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550 U.S.A., pyle4@llnl.gov, walter5@llnl.gov Search other works by this author on: GSW Google Scholar William R. Walter Bulletin Seismological Society America (2019) 109 (3): 1071–1081. https://doi.org/10.1785/0120180256 Article history first...

Analysis of seismic records local earthquakes and a series underground chemical explosions conducted during the Source Physics Experiment (SPE) at Nevada National Security Site (NNSS) have shown that distances (

Mining of the database produced by seismic array stations International Monitoring System has resulted in hundreds new observations precritical reflections from Earth's inner core. Here we present short‐period amplitude ratios between these PKiKP phases and corresponding ( PcP ) core‐mantle boundary (CMB). / are one few that directly constrain change S velocity density across core‐outer core boundary. We measure optimally tuned beams use a bootstrap technique to estimate observational...

ABSTRACT Seismologists distinguish underground nuclear explosions from more commonly occurring earthquakes using moment tensor inversion, high-frequency P/S amplitude ratios, mb:Ms comparisons, and P-pP differential travel times. These methods are generally successful for large seismic events (M>3–4) well recorded at regional-to-teleseismic distances (>150 km); however, it is unclear whether they can be modified to work small (M<3) only local (<150 km). Here, we...

We have assembled a data set of 302 differential PKiKP ‐ PcP travel times that were recorded by seismic array stations the International Monitoring System. This is an order magnitude more than all previous observations combined. The measured using beam‐forming and cross‐correlation algorithm has precision 1–2 sampling intervals (<0.1 s). use mitigates effects hypocentral errors heterogeneities in crust upper mantle, leaving sensitive to deep Earth structure. are especially variations...

We derive a model for crustal shear wave velocities in the Transantarctic Mountains and surrounding areas of East Antarctica Ross Sea region West using Rayleigh Green's functions estimated from cross correlation ambient seismic noise recorded by Seismic Experiment. Group velocity maps are determined travel times measured waves filtered at periods between 5 23 s. The inverted across niching genetic algorithm. observe only minor variation beneath Mountains, similar to those observed...

Abstract We investigate source locations of P wave microseisms within a narrow frequency band (0.67–1.33 Hz) that is significantly higher than the classic microseism (~0.05–0.3 Hz). Employing backprojection method, we analyze data recorded during January 2010 from five International Monitoring System arrays border Pacific Ocean. develop ranking scheme allows us to combine beam power multiple obtain robust microseisms. Some individual exhibit strong regional component, but results combination...

Abstract Accurate event locations are important for many endeavors in seismology, and understanding the factors that contribute to uncertainties those is complex. In this article, we present a case study takes an in-depth look at accuracy precision possible locating nine shallow earthquakes Rock Valley fault zone southern Nevada. These events targeted by Direct Comparison phase of Source Physics Experiment, as candidates colocation chemical explosion with earthquake hypocenter directly...

We examine the seismic structure of Mariana mantle wedge using data from a combined deployment ocean bottom seismographs and land stations in 2003–2004. measure Rayleigh wave phase velocities invert these results for shear velocity azimuthal anisotropy region. In back‐arc region low indicate as 3.9 ± 0.1 km/s at depths about 60 km. Locations lowest 18.0°N–18.5°N, 16.0°N–16.5°N, 14.0°N–14.5°N correspond to locations gravity lows probably presence temperature melt production maxima compared...

Abstract A series of four chemical explosions were detonated in a deep borehole within the Yucca Flat Dry Alluvium Geology (DAG) at Nevada National Security Site between 2018 and 2019. The two larger 50 tons (DAG‐2) 10 (DAG‐4) TNT equivalent yield triggered energetic aftershock sequences numbering 1392 347 microearthquakes, respectively, first days. No significant activity was observed for smaller 1‐ton (DAG‐1 DAG‐3). We used back‐projection method based on travel‐time migration stacking...

Abstract High-frequency (∼> 2 Hz) seismic P/S amplitude ratios are well-established as a discriminant to distinguish between natural earthquakes and underground explosions at regional distances (∼200–1500 km). As research shifts toward identifying lower-yield events, work has begun investigate the potential of this for use local (<200 km), in which initial results raise questions about its effectiveness. Here, we utilize data from several chemical explosion experiment series...

Research Article| October 24, 2017 High‐Resolution 2D Lg and Pg Attenuation Models in the Basin Range Region with Implications for Frequency‐Dependent Q Moira L. Pyle; Pyle aLawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, pyle4@llnl.gov, walter5@llnl.gov, pasyanos1@llnl.gov Search other works by this author on: GSW Google Scholar William R. Walter; Walter Michael E. Pasyanos Bulletin of Seismological Society America (2017) 107 (6): 2846–2858....

The Source Physics Experiment (SPE) is a series of chemical explosions at the Nevada National Security Site (NNSS, formerly Test Site) designed to improve our understanding explosion physics. A future SPE will place an hypocenter small, shallow earthquake, providing direct earthquake‐to‐explosion experiment. Candidate earthquakes for this novel experiment come from sequence over 200 unusually events that occurred in Rock Valley, Nevada, southeastern portion NNSS during 1993. We apply...

Induced seismicity is inherently associated with underground fluid injections, including during geologic carbon sequestration. If fluids are injected in proximity to a pre-existing fault or fracture system, the resulting elevated pressures can trigger dynamic earthquake slip, which could both damage surface structures and create new migration pathways. The goal of this research develop fundamentally better approach geological site characterization early hazard detection. We combine...