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Assembling a Nevada 3D Velocity Model: Earthquake-Wave Propagation in the Basin & Range, and Seismic Shaking Predictions for Las Vegas John N. Louie (University of Nevada, Reno) The development of an open-source 3d modeling environment allows seismologists, explorationists, engineers, and students to predict wave propagation through geologically complex regions. The environment combines geologic and geotechnical data sets with gridding, modeling, and output specifications into portal packs for execution on standalone workstations, clusters, and supercomputing grids. A tutorial interface helps the user scale the grid to the facilities available, from small test runs to efforts requiring major resources. The ability to configure computations at a range of scales and model complexity is intended to promote wide use of advanced seismic modeling. Geologic models can include many basins in addition to the target urban basin, and detailed geotechnical information where available. To predict earthquake shaking in Nevada urban areas, the 3d model assembles several data sets at a wide variety of scales, from regional geologic maps to shallow shear-velocity measurements from microtremor transects having 0.3-km spacing (fig. 1). For Las Vegas the principal earthquake hazard is from the Furnace Creek fault system, capable of M7.5 events. Peak ground velocity (PGV) results from finite-difference wave modeling at 0.3 Hz show no obvious correlation between amplification and basin depth or dip of the basin floor. Animations of shaking show the expected strong trapping and long shaking durations within basins, as well as diffusion and scattering of energy between the many basins in the region. The two Furnace Creek scenarios tested, involving rupture away from and toward Las Vegas, produced unexpectedly different PGV in the city (fig. 2). Rupture directivity toward the city may amplify shaking by a factor of fifteen at some locations. Despite affecting only the very shallowest zone of models (
Optimized Velocities and Prestack Depth Migration in the Reno- Area Basin John N. Louie (University of Nevada, Reno), Satish Pullammanappallil (Optim, Inc.), Annie Kell-Hills (University of Nevada, Reno) We collected seismic reflection profiles in the Reno, Nevada area basin in collaboration with the USGS and nees@UTexas during June 2009. Stratigraphic horizons and vertical offsets associated with faulting appear along a 6.72 km Truckee River profile while strong, horizontally propagating body waves are seen in shot gathers from the southern 3.84 km Manzanita Lane profile (fig. 1). Reno-area basin fill overlies Miocene andesitic volcanic rocks and consists of Neogene sedimentary rocks and Quaternary outwash deposits. Using the seismic shot records, we created optimized velocity models of the Reno basin using commercial SeisOpt®@2D software. The refracted P-wave arrivals provide inputs for a global velocity model over the length of the profiles and to a depth proportional to the source offset distances, expected to be 150-200 m. Within this basin most of the lateral velocity heterogeneity appears within 200 m of the surface. Comparing this velocity model to stacked sections produced by the USGS added confidence to the interpretations of strong reflection boundaries seen in the seismic sections (fig. 2). Boundaries in the velocity model coincide with prominent reflection boundaries as well as with known depths of volcanic fill and other deposits, constraining their depths and velocities. The tomographic velocity sections were then used as input with the shot records to a Kirchhoff pre-stack depth migration (PSDM) imaging steeply dipping structure and further constraining current interpretations and fault/basin geometry. The PSDM resolved the cause of the horizontally propagating waves seen along Manzanita Lane as sidewall reflections from a steeply dipping fault (fig. 3). Acknowledgements: Research supported by the U.S. Geological Survey (USGS), Department of the Interior, under USGS award numbers G09AP00051, 08HQGR0015, and 08HQGR0046. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government. Figure 1: Two shot records from the Manzanita Lane survey, south Reno, showing strong horizontally-propagating body waves originating at surface fault traces. Figure 3: Portion of the depth section, 1.4 km long extending to 1000 m depth, running west (left) to east (right) along Manzanita Lane in south Reno. No vertical exaggeration- local ground surface is at 150 m depth on the vertical scale. The horizontally propagating waves image into a combination of a steeply dipping fault structure (dashed purple line) and a shallow-dipping structure (solid purple line). Figure 2: Depth section 2.3 km long extending to 1000 m depth, running west (left) to east (right) along the Truckee River through downtown Reno. No vertical exaggeration. Colors indicate velocities optimized from 1st-arrival picks, with Quaternary gravels (green) overlying Tertiary sands (red). The reflections are interpreted as showing two west-dipping normal faults (blue lines). 2010 IRIS Core Programs Proposal | Volume II | Crustal Structure | II-123
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volume ii - accomplishments Facilit
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volume ii - accomplishments Facilit
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CONTENTS Introduction..............
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Non-Volcanic Tremor along the Oaxac
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Detecting the Limit of Slab Break-o
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Lower Mantle, Core-Mantle Boundary
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• Non-Earthquake Seismic Sources
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acoustics community by permitting a
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Near-Surface Environments - Hazards
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Why Do Faults Slip? Emily Brodsky (
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Another probe of fault evolution is
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to provide a best match with the Gl
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tectonic disruption and mass accumu
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W3 ∆ 5 . A number of intriguing r
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thermal and compositional effects r
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Towards a Global School Seismic Net
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On-Line Seismology Curriculum for U
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Teachers on the Leading Edge: Earth
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USArray Education and Outreach in S
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From an IRIS Lecture Tour to a Gene
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Explorer Series Robert Bartolotta (
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Workshop “Earth System Science fo
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The IRIS Internship Cycle: From Int
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Community-Outreach Efforts in Data
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Site Reconnaissance for Earthscope
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jAmaseis: Seismology Software Meeti
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Near Real-Time Simulations of Globa
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FuncLab: A MATLAB Interactive Toolb
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Five Years of Distributing the Seis
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IRIS DMS Data Products, Beyond Raw
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Local Earthquakes in the Dallas-Ft.
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Epicentral Location Based on Raylei
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Analysis of Spatial and Temporal Se
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Exceptional Ground Motions from the
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The 2010 Mw7.2 El Mayor-Cucapah Ear
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Effects of Kinematic Constraints on
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Imaging of the Source Properties of
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Teleseismic Inversion for Rupture P
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The Global Aftershocks of the 2004
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The 17 July 2006 Java Tsunami Earth
Page 83 and 84: Seismic Cycles on Oceanic Transform
Page 85 and 86: Migration of Early Aftershocks Foll
Page 87 and 88: Apparent Stress Variations at the O
Page 89 and 90: Automated Identification of Telesei
Page 91 and 92: Evaluating Ground Motion Prediction
Page 93 and 94: Tremor Monitoring Aaron Wech (Unive
Page 95 and 96: Slow Slip and Tremor in the Norther
Page 97 and 98: 0 0.5 1 1.5 2 2.5 3 0 0.5 1 1.5 2 2
Page 99 and 100: Intimate Details of Tremor Observed
Page 101 and 102: Global Search of Triggered Tremor a
Page 103 and 104: Slab Morphology in the Cascadia For
Page 105 and 106: Source Analysis of the Memorial Day
Page 107 and 108: Iceberg Tremor and Ocean Signals Ob
Page 109 and 110: Elucidating the Stick-Slip Nature o
Page 111 and 112: Probing the Atmosphere and Atmosphe
Page 113 and 114: Volcanic Plume Height Measured by S
Page 115 and 116: Eruption Dynamics at Mount St. Hele
Page 117 and 118: A Search for the Lunar Core Using A
Page 119 and 120: Seismic Imaging of the Mt. Rose Fau
Page 121 and 122: Structure of the California Coast R
Page 123 and 124: Temporal Variations in Crustal Scat
Page 125 and 126: High-Resolution Locations of Trigge
Page 127 and 128: Adjoint Tomography of the Southern
Page 129 and 130: Crustal Structure of the High Lava
Page 131 and 132: Controlled Source Seismic Experimen
Page 133: Structural Interpretations Based on
Page 137 and 138: 40 Crustal Structure beneath the Hi
Page 139 and 140: Controlled-Source Seismic Investiga
Page 141 and 142: Northward Thinning of Tibetan Crust
Page 143 and 144: An Integrated Analysis of an Ancien
Page 145 and 146: Crustal Velocity Structure of Turke
Page 147 and 148: Ambient Noise Tomography of the Pam
Page 149 and 150: Ambient Noise Monitoring of Seismic
Page 151 and 152: Mushy Magma beneath Yellowstone Ris
Page 153 and 154: Imaging the Seattle Basin to Improv
Page 155 and 156: Developing a Database of ENA Ground
Page 157 and 158: Lithospheric Layering in the North
Page 159 and 160: eflective zones on depthmigrated se
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Page 163 and 164: S-Velocity Structure of Cratons, fr
Page 165 and 166: Seismic Structure of the Crust and
Page 167 and 168: Subducted Oceanic Asthenosphere and
Page 169 and 170: Detecting the Limit of Slab Break-o
Page 171 and 172: Pn Tomography of the Western United
Page 173 and 174: 3-D Isotropic Shear Velocity Model
Page 175 and 176: Seismic Anisotropy Associated with
Page 177 and 178: Anisotropy in the Great Basin from
Page 179 and 180: Source-Side Shear Wave Splitting an
Page 181 and 182: S-Velocity Structure of the Upper M
Page 183 and 184: Velocity Structure of the Western U
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Segmented African Lithosphere benea
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Imaging the Mantle Wedge in the Cen
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A Slab Remnant beneath the Gulf of
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Imaging the Southern Alaska Subduct
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Opposing Slabs under Northern South
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Effect of Prior Petrological Constr
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Global Azimuthal Seismic Anisotropy
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The Stratification of Seismic Azimu
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Upper Mantle Anisotropy beneath the
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The Teleseismic Signature of Fossil
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Seismic Anisotropy under Central Al
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Stress-Induced Upper Crustal Anisot
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Tau-p Depropagation of Five Regiona
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Mapping the Upper Mantle with the S
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Upper Mantle Structure of Southern
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The Africa-Europe Plate Boundary in
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The Isabella Anomaly Imaged by Eart
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Tomographic Image of the Crust and
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Small-Scale Mantle Heterogeneity an
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Mantle Heterogeneity West and East
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New Geophysical Insight into the Or
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The Plume-slab Interaction beneath
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Imaging the Shear Wave Velocity "Pl
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Slab Fragmentation and Edge Flow: I
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Mantle Shear-Wave Velocity Structur
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Discordant Contrasts of P- and S-Wa
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Upper Mantle Discontinuity Topograp
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Edge-Driven Convection beneath the
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Imaging Attenuation in the Upper Ma
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Three-Dimensional Electrical Conduc
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Core-Mantle Boundary Heat Flow Thor
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Constraints on Lowermost Mantle Ani
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Localized Double-Array Stacking Ana
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Waveform Modeling of D" Discontinui
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Absence of Ultra-Low Velocity Zones
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Moving Seismic Tomography Beyond Fa
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A Three-Dimensional Radially Anisot
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The Importance of Crustal Correctio
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Slabs Do Not Go Gentle Karin Sigloc
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Localized Temporal Change of the Ea
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Core Structure Reexamined Using New
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Large Variations in Travel Times of
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Observations of Antipodal PKIIKP Wa
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Regional Variation of Inner Core An
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Wide-Scale Detection of Earthquake
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