Number of products tagged with
**emc_1**
(41).

## EMC IRIS Earth Model Collaboration

A repository of Earth models with the aim of providing the research community with access to various Earth models, visualization tools for model preview, facilities to extract model data/metadata and access to the contributed processing software and scripts.

## EMC-ak135-f ak135-f velocity model, ak135 full model

ak135-f is a variant of the ak135 velocity model, Kennett, Engdahl & Buland (1995) , which is obtained by augmenting it with the density and Q model of Montagner & Kennett (1995) .

## EMC-Cascade.ANT.Gao-Shen.2014 3D shear-wave velocity model of the Cascades from full-wave ambient noise tomography

Cascade.ANT.Gao-Shen.2014, Gao and Shen (2014), is based on a full-wave ambient noise tomographic method and the analysis of Rayleigh waves from ~1000 stations between 1995 to 2012, including the EarthScope USArray Transportable Array and many other permanent and flexible arrays.

## EMC-ContributionGuide IRIS EMC - Model Contribution Guidelines

EMC, as a repository of the Earth models, provides research community with access to various tomographic models, visualization tools for model preview and access to the contributed processing software and scripts.

## EMC-DesktopTools IRIS EMC - Desktop Tools

The contributed Earth models to EMC are available for download from the model overview pages or IRIS’ Searchable Product Depository (SPUD) in netCDF (network Common Data Form) format. These models are compatible with those desktop visualization systems that support netCDF data files. This page provides a short introduction on installation and model loading for some free Java-based desktop applications that allow 3-D visualization of complex solid earth data.

## EMC-DNA09 Earth model DNA09

DNA09, Obrebski, Allen, Xue & Hung (2010) , model is obtained through the body wave finite frequency tomographic inversion of the available EarthScope-USArray data recorded from January 2006 to July 2009.

## EMC-DNA10-S Earth model DNA10-S

DNA10-S model, Obrebski, Allen, Pollitz & Hung (2011), integrates teleseismic body-wave traveltime and surface-wave phase velocity measurements into a single inversion to constrain the S-wave velocity structure beneath the western US.

## EMC-DNA13 Earth model DNA13

DNA13 model, Porritt, Allen, & Pollitz (2014), provides three independent body-wave derived estimates of the wave-speed for the continuous US. Teleseismic and ambient noise derived phase velocities are utilized in a joint inversion with the SV component body waves.

## EMC-DNA13-Supplemental Supplemental information on DNA13 Earth model

DNA13 model, Porritt, Allen, & Pollitz (2014), provides three independent body-wave derived estimates of the wave-speed for the continuous US. Teleseismic and ambient noise derived phase velocities are utilized in a joint inversion with the SV component body waves. This page contains supplemental information on resolution, phase ray and phase velocity as well as uncertainties for this model.

## EMC-EarthModels IRIS EMC - Earth Models

The following models are contributed to the IRIS EMC by various researchers. Linked model names point to a dedicated page for the model that provides model information and download links.

## EMC-ExtractingData Extracting Data from the netCDF Earth Model Files

There is a “large collection of codes and tools available for manipulating the netCDF Files. This page provides examples of how two of these tools (ncdump and ncks) could be used to extract information from the netCDF model files.

## EMC-GyPSuM Earth model GyPSuM

GyPSuM, Simmons, Forte, Boschi & Grand (2010) , is a tomographic model of mantle seismic wave speeds developed through simultaneous inversion of seismic body wave travel times and geodynamic observations.

## EMC-HMSL-P06 Earth model HMSL-P06

HMSL-P06, Houser et al. (2008) , is an isotropic P velocity model with 18 layers (approximately 100 km thickness in the upper mantle and 200 km in the lower mantle) and 2578 blocks in each layer (approximately 4 degree equal area blocks at the equator).

## EMC-HMSL-S06 Earth model HMSL-S06

HMSL-S06, Houser et al. (2008) , is an isotropic shear velocity model with 18 layers (approximately 100 km thickness in the upper mantle and 200 km in the lower mantle) and 2578 blocks in each layer (approximately 4 degree equal area blocks at the equator).

## EMC-iasp91 iasp91 velocity model

The iasp91 reference model is a parameterised velocity model that has been constructed to be a summary of the travel time characteristics of the main seismic phases, Kennett (1991).

## EMC-LLNL-G3Dv3 Earth model LLNL-G3Dv3

Simmons, Myers, Johannesson & Matzel (2012) , is a global-scale model of the crust and mantle P-wave velocity with regional-scale details. The model is parameterized using a spherical tessellation with node spacing of ~1 degree in the upper mantle and ~2 degrees in the lower mantle.

## EMC-NA04 North American upper mantle surface wave tomography model

NA04, van der Lee and Frederiksen (2005) , is derived from inversion of the fundamental and higher mode Rayleigh waveforms using the Partitioned Waveform Inversion technique, Nolet (1990). The data set used includes waveforms from about 1400 regional seismograms recorded at North American digital broadband seismic stations (including the USArray Transportable Array waveforms). The NA04 3-D model is expressed as the velocity difference in m/s relative to the 1-D averaged Earth model MC35 .

## EMC-NA07 North American upper mantle surface wave tomography model

NA07, Bedle and van der Lee (2009) , is based on the 3-D shear velocity model NA04 and the analysis of regional S and Rayleigh waveforms for earthquakes around North America from January 2000 through September 2006, including waveforms from the USArray Transportable Array stations. The NA07 3-D model is expressed as velocity difference in m/s relative to the 1-D averaged Earth model MC35.

## EMC-NWUS11-P A 3-D P-wave tomography model for the northwestern United States

A 3-D P-wave tomography model for the northwestern United States, James et al. (2011) . The P-wave inversion for NWUS11-P is based on a total of 79,212 rays from 461 teleseismic events, with typical bandpass filter range of 0.5-1.5 Hz. The percent velocity perturbations reported by this model are insensitive to the starting 1-D reference model.

## EMC-NWUS11-S A 3-D S-wave tomography model for the northwestern United States

A 3-D S-wave tomography model for the northwestern United States, James et al. (2011) . The S-wave inversion is based on a total of 88,689 rays from 379 teleseismic events, with typical bandpass filter ranges of 0.04-0.15 Hz. The percent velocity perturbations reported by this model are insensitive to the starting 1-D reference model.

## EMC-PEM Parametric Earth Models

Parametric Earth Models (PEM) — Three models (Average, Continental & Oceanic) that were introduced by Dziewonski, Hales and Lapwood (1975) for which the radial variations of density and velocity are represented by piecewise continuous analytical functions of radius. All three models are identical below a depth of 420 km.

## EMC-PNW10-S S-velocity model of the Cascadia Subduction Zone

PNW10-S, Porritt et al. (2011) , PNW10-S combines the state of the art ambient noise tomography method with time tested analyst selection to ensure the highest quality data is used as input to the model inversion. Incorporating spatially and temporally long paths with this manual selection step allows recoverable structure from the surface to ~120km depth. This model focuses on the US Pacific Northwest to address a series of questions relating to variations in arc volcanism, seismicity, tremor activity, and the relation to subduction complex structure.

## EMC-PREM Preliminary Reference Earth Model

(referenced by GyPSum , SAW24B16 and as **PREM500** by SAW642AN and SAW642ANb ) The Preliminary Reference Earth Model, Dziewonski and Anderson (1981) , is an average Earth model that incorporates anelastic dispersion and anisotropy and therefore it is frequency-dependent and transversely isotropic for the upper mantle.

## EMC-QRLW8 A global upper mantle shear wave attenuation model

A degree 8 3-D Q model of the upper mantle by Gung and Romanowicz (2004) , derived from three component surface waveform data in the period range of 60-400 seconds. Model is parameterized in spherical harmonics for lateral variations and cubic b-splines for depth dependence up to maximum spherical harmonics degree 16 horizontally for the SV-velocity model and 8 for the Q model with the use of 16 B-splines vertically (throughout the mantle). The velocity model is expressed as perturbations from the spherically symmetric model PREM .

## EMC-ReferenceModels IRIS EMC - Reference Earth Models

Most of the EMC Earth models are expressed as perturbations relative to a particular 1-D reference Earth model. This page provides access to some reference Earth models that are hosted by EMC or hosted externally.

## EMC-References IRIS EMC References

IRIS Earth Model Collaboration – Publications cited by the IRIS EMC pages

## EMC-S2.9EA A global model with higher resolution in the upper mantle beneath Eurasia

S2.9EA, Kustowski, Ekstrom and Dziewonski (2008A) , laterally parametrize the upper-mantle structure beneath Eurasia using spherical splines with ˜2.9° spacing in Eurasia and ˜11.5° spacing elsewhere. The model is obtained from a combined data set of surface wave phase velocities, long-period waveforms and body-wave traveltimes. The 1-D reference model is STW105 .

## EMC-S362ANI A global model of shear-wave velocity

S362ANI, Kustowski, Ekstrom and Dziewonski (2008) , has its radial anisotropy confined to the uppermost mantle (that is, since the anisotropy is parameterized with only the four uppermost splines, it becomes very small below a depth of 250 km, and vanishes at 410 km). The 1-D reference model is “STW105”../../referencemodels/emc-stw05 .

## EMC-S362WMANI Anisotropic (anisotropy allowed throughout the mantle) S velocities

S362WMANI, Kustowski, Ekstrom and Dziewonski (2008) , is a version of S362ANI with anisotropy allowed throughout the mantle. The 1-D reference model is STW105 .

## EMC-SAW24B16 A global shear velocity structure of the mantle from body, surface and higher-mode waveforms

A 3-D shear velocity structure of mantle based on the inversion of body, surface, and higher mode waveforms, Megnin and Romanowicz (2000) . The model was derived from handpicked transverse component waveforms and is parameterized laterally in spherical harmonics up to degree 24 (Edmonds normalization) and radially in 16 unevenly spaced splines. The SAW24B16 model is expressed as the percent perturbation from PREM .

## EMC-SAW642AN A global radially anisotropic mantle shear velocity model

SAW642AN, Panning and Romanowicz (2006) , is a radially anisotropic shear velocity model, parameterized in terms of isotropic S velocity (Voigt average) and the anisotropic parameter, xi (VSH2/VSV2). Model values are percent perturbation relative to the anisotropic reference model PREM500 .

## EMC-SAW642ANb A global radially anisotropic mantle shear velocity model with improved crustal corrections

SAW642ANb, Panning, Lekic and Romanowicz (2010) , is a radially anisotropic shear velocity model of the mantel, parameterized in terms of isotropic S velocity (Voigt average) and the anisotropic parameter, xi (VSH2/VSV2). The waveform data used for this model consist of 3-component broad-band surface waveforms (short period corner of 80 seconds and cutoff of 60 seconds) as well as body waveforms (short period corner of 40 s and cutoff of 32 s). The spatial parameterization of the model is the same as SAW642AN , with 16 variably spaced cubic b-splines with depth, and level 4 spherical splines laterally. Model values are percent perturbation relative to the anisotropic reference model PREM500 .

## EMC-SAWum_NA2 A high-resolution North American model of upper mantle structure

SAWum_NA2 North American regional shear velocity model is an isotropic and radially and azimuthally anisotropic Vs model for the North American upper mantle. The isotropic and radial anisotropic portion of the model is developed using long period 3-component fundamental and overtone surface waveforms in the frame work of the Non-linear normal Mode Asymptotic Coupling Theory (Li and Romanowicz, 1995;1996). A joint inversion of surface waveforms and SKS station average datasets is used in the azimuthal anisotropy inversion (Montagner et al. 2000; Romanowicz and yuan 2012).

## EMC-SEMum A high-resolution global model of upper mantle structure

SEMum is a radially anisotropic shear velocity model, parametrized in terms of isotropic S velocity (Voigt average) and the anisotropic parameter, xi (V _{sh} ^{2} /V _{sv} ^{2} ). The Vs (xi) model is parametrized in terms of 2562 (642) spherical splines laterally, and 16 irregularly spaced cubic b-splines radially.

## EMC-SRPY-MT Regional 3-D electrical conductivity model of Snake River Plain / Yellowstone, USA based on magnetotelluric data

A 3-D regional electrical conductivity model of the crust and upper mantle beneath the Yellowstone/Snake River Plain volcanic province (Idaho and Wyoming, United States) based on magnetotelluric data, Kelbert, Egbert, and deGroot-Hedlin (2012) .

## EMC-STW105 Reference Earth Model also known as REF

STW105 (also known as REF) is a transversely isotropic reference Earth model, Kustowski, Ekstrom and Dziewonski (2008).

## EMC-TNA_SNA Average of the TNA and SNA models

An average of the TNA (Tectonic North America) and SNA (Shield North America) S velocity models of Grand and Helmberger (1984)

## EMC-TX2000 A global mantle shear-wave tomography model

TX2000 (also called Grand2000) refers here to the TXBW, Grand (2002) , model to distinguish it from the TXBW Grand, van der Hilst and Widiyantoro (1997) model. The model is derived from the shear body wave travel times and aims at providing a more uniform global coverage of the mantle and more information on the upper-mantle seismic structure by using analysis of multibounce shear waves, core-reflected waves and SKS and SKKS waves that travel through the core.

## EMC-TX2011 A global shear-wave tomography model

TX2011 provides shear velocity perturbations with respect to the TX2011_ref reference model with the mean from the individual layers removed. The grid is not representative of the block size used in the inversion. The model assumes the crustal thickness is given by the Mooney, Laske and Masters crustal model, Mooney et al. (1998) , and thus velocity deviations in the upper most layer are with respect to a variable crustal thickness model.