UCVM User Guide

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Contents

Overview

The Unified California Velocity Model Framework UCVM is a software package that allows the user to directly query multiple velocity models in a program and to combine them into a composite model. UCVM supports querying from many standard velocity models, including SCEC CVM-H, and SCEC CVM-S. This software may also be easily extended to support any user-defined crustal or GTL model as long as that model can be expressed in a C header and source/library file. The API itself is written in the C language.

The software is MPI-capable, and has been shown to scale to 3300+ cores on NICS Kraken in a mesh generator. It allows application programs to tailor which set of velocity models are linked in to minimize memory footprint. It is also compatible with grid resources that have data stage-in policies for jobs, and light-weight kernels that support static libraries only. This package has been tested on NCCS Jaguar, NICS Kraken, and USC HPCC.


Requirements

The system requirements are as follows:

  1. UNIX operating system (Linux, Solaris, MacOS)
  2. GNU gcc/gfortran compilers (MPI wrappers such as mpicc are OK)
  3. tar for opening the compressed files
  4. Euclid Etree library Euclid Etree
  5. Proj.4 projection library Proj.4


Installation

Download

  1. Start at SCEC website: http://scec.usc.edu/scecpedia/UCVM
  2. Navigate to the Downloads section of the UCVM web page.
  3. Click the download link to download the latest source code distribution file and any listed dependencies. This is typically posted as a tar and gzipped file (tgz format). The source code distribution file is large (280 Mb), so the download make take awhile.


CheckSum Test

Not currently implemented.


Basic Install

The general steps for installing UCVM are:

  1. Install Etree and Proj.4 packages
  2. Install one or more velocity models
  3. Define environment variables describing where Etree/Proj.4/models are located
  4. Run the UCVM installer


First, install the Etree and Proj.4 packages which are required by UCVM. The INSTALL/README instructions in each distribution describe how to install them, but generally:

For the Euclid Etree library: 

% tar xvf euclid-latest.tar
% cd ./euclide-3.12/libsrc
% make all

If installing the Etree library on a Lustre filesystem (NICS Kraken, TACC Ranger, NCCS Jaguar), you must enable IOBUF. Please see Cvmbycols#Technical_Note_for_Lustre_Filesystems for special installation instructions.

For the Proj.4 library: 

% tar xvf proj-4.7.0.tar
% cd proj-4.7.0
% ./configure --prefix=<your desired install directory>
% make; make install

Be sure to note where you installed these two packages. You will need this information later in the installation process.

Then, install the velocity models that you wish to use with UCVM according to the documentation provided by those models. Ensure they are compiled with gcc/gfortran.

For the SCEC CVM-H model: 

% tar xvf cvmh-11.9.0.tar.gz
% cd cvmh-11.9.0
% ./configure --prefix=desired_install_dir
% make; make install


For the SCEC CVM-S model: 

% tar xvf cvms-11.9.0.tgz
% cd cvms/src
% make all


Again, be sure to note where you installed the community velocity models.

Declare environment variables with the paths to the Etree library, Proj.4 library, and velocity models that you previously installed. Also, update your LD_LIBRARY_PATH environment variable to include the new library directories. 

ETREE_DIR=<Etree install path>
PROJ4_DIR=<Proj.4 install path>
CVMH_DIR=<CVM-H install path>
CVMS_DIR=<CVM-S install path>
LD_LIBRARY_PATH=${ETREE_DIR}/libsrc:${PROJ4_DIR}/lib:${CVMH_DIR}/lib:${CVMS_DIR}/lib:${LD_LIBRARY_PATH}
UCVM_INSTALL_DIR=<desired UCVM install path>


In a bash shell, for example, the ETREE_DIR environment variable can be declared with the command: 

% ETREE_DIR=/opt/etree;export ETREE_DIR

In a csh shell: 

% setenv ETREE_DIR /opt/etree

Now unpack the UCVM software distribution: 

% tar zxvf ucvm-11.9.0.tar.gz

The build configuration differs slightly depending on where you wish to run UCVM. On a standard Linux system with gcc, run the following commands to build the software with CVM-H and CVM-S enabled: 

% cd ucvm-11.9.0
% ./configure --prefix=${UCVM_INSTALL_DIR} --with-etree-include-path="${ETREE_DIR}/libsrc" 
 --with-etree-lib-path="${ETREE_DIR}/libsrc" --with-proj4-include-path="${PROJ4_DIR}/include" 
 --with-proj4-lib-path="${PROJ4_DIR}/lib" --enable-model-cvmh --enable-model-cvms 
 --with-cvmh-include-path="${CVMH_DIR}/include" --with-cvmh-lib-path="${CVMH_DIR}/lib" 
 --with-gctpc-lib-path="${CVMH_DIR}/gctpc/lib" --with-cvms-include-path="${CVMS_DIR}/include" 
 --with-cvms-lib-path="${CVMS_DIR}/lib" --with-cvmh-model-path="${CVMH_DIR}/model" --with-cvms-model-path="${CVMS_DIR}/src"
% make

The above example enables CVM-H and CVM-S but any of the following models may be enabled: SCEC CVM-H, SCEC CVM-S, SCEC CVM-SI, USGS CenCalVM, and WFCVM. For each velocity model you want to use, the configure script needs to be told to explicitly use that model (with the --enable-model-* flag) and where to find the velocity model's library files (.a or .so), header files (.h), and model files so that they can be linked into UCVM.

Note that unless you force static linking with the "--enable-static" command line option, you must update your LD_LIBRARY_PATH environment variable with the paths to the Etree, Proj.4, and model shared libraries.


The configure command is quite long, so an example shell script with this command is located in ./scripts/autoconf/basic_install.sh. It assumes that you previously defined the environment variables described in this installation guide. The script can be executed with the following shell commands: 

% cd scripts/autoconf
% ./basic_install.sh


Check that the package was built correctly with the following command: 

% make check

Verify that all unit tests and acceptance tests pass.

Install the software to the desired target location with the following command: 

% make install


A full list of supported standard velocity models and options can be listed with the command 

% ./configure --help


Updating the Configuration

The UCVM installer will automatically create a configuration file in ${UCVM_INSTALL_DIR}/conf/ucvm.conf with entries for all enabled velocity models and some standard settings. However, you may wish to edit this file to toggle model flags or to add new user models in the future. For example, the CVM-H model has a number of flags that may be set in the UCVM configuration file. Please see UCVM_User_Guide#Framework_Configuration for more details.


Advanced Install

Additional options must be passed to the ./configure script on a more exotic Linux system, such as a host that requires static linking (NICS Kraken), or has a Lustre high-performace filesystem (TACC Ranger). The following example shows how to enable static linking and IOBUF buffering: 

% cd ucvm-11.9.0
% module add iobuf
% ./configure --prefix=${UCVM_INSTALL_DIR} --enable-static --enable-iobuf --enable-model-cvmh --enable-model-cvms
--with-etree-include-path="${ETREE_DIR}/libsrc" --with-etree-lib-path="${ETREE_DIR}/libsrc" 
--with-proj4-include-path="${PROJ4_DIR}/include" --with-proj4-lib-path="${PROJ4_DIR}/lib" 
--with-cvmh-include-path="${CVMH_DIR}/include" --with-cvmh-lib-path="${CVMH_DIR}/lib" 
--with-gctpc-lib-path="${CVMH_DIR}/gctpc/lib" --with-cvms-include-path="${CVMS_DIR}/include" 
--with-cvms-lib-path="${CVMS_DIR}/lib" --with-cvmh-model-path="${CVMH_DIR}/bin" --with-cvms-model-path="${CVMS_DIR}/src" CC=cc
% make; make check; make install

A few notes:

  • Some systems require applications to be linked statically (example above).
  • Lustre filesystems require linking with IOBUF module (NICS Kraken example above).
  • The configure script needs to be told where to find the library file(s), the header file(s), and the model files for each velocity model that you wish to enable. The configure script will check that the libraries and headers are present, and it will setup UCVM with that model enabled and properly configured.
  • The script will attempt to auto-detect a GNU compliant compiler. If an MPI wrapper is found, the MPI version of UCVM is compiled, otherwise the serial version is built. The compiler may be overridden with the option 'CC="mpicc"' for example.
  • Additional compiler flags and linker flags may be passed to ./configure with the CFLAGS and LDFLAGS options. Generally, this is not needed but allows the package to be built on platforms with specific compiling/linking requirements.


The full list of options follows: 

  --enable-static         enable static linking
  --enable-iobuf          enable IOBUF module
  --enable-model-cvmh     enable model SCEC CVM-H
  --enable-model-cvms     enable model SCEC CVM-S
  --enable-model-cencal   enable model USGS CenCalVM
  --enable-model-cvmsi    enable model SCEC CVM-SI
  --enable-model-wfcvm    enable model WFCVM

  --with-etree-include-path
                          location of the Etree headers
  --with-etree-lib-path   location of the Etree libraries

  --with-proj4-include-path
                          location of the Proj.4 headers
  --with-proj4-lib-path   location of the Proj.4 libraries

  --with-cencal-include-path
                          location of the USGS CenCalVM headers
  --with-cencal-lib-path  location of the USGS CenCalVM libraries
  --with-cencal-model-path
                          location of the USGS CenCalVM high-rez etree
  --with-cencal-extmodel-path
                          location of the USGS CenCalVM extended etree

  --with-cvmh-include-path
                          location of the SCEC CVM-H headers
  --with-cvmh-lib-path    location of the SCEC CVM-H libraries
  --with-cvmh-model-path  location of the SCEC CVM-H model files
  --with-gctpc-lib-path   location of the CVM-H GCTPC libraries

  --with-cvms-include-path
                          location of the SCEC CVM-S headers
  --with-cvms-lib-path    location of the SCEC CVM-S libraries
  --with-cvms-model-path  location of the SCEC CVM-S model files

  --with-cvmsi-include-path
                          location of the SCEC CVM-SI headers
  --with-cvmsi-lib-path   location of the SCEC CVM-SI libraries
  --with-cvmsi-model-path location of the SCEC CVM-SI model files

  --with-wfcvm-include-path
                          location of the WFCVM headers
  --with-wfcvm-lib-path   location of the WFCVM libraries
  --with-wfcvm-model-path location of the WFCVM model files


Unit and Acceptance Tests

Unit tests may be executed with the command: 

% make check

All unit tests should result in a PASS.

Acceptance tests may be executed with the command: 

% make check

All acceptance tests should result in a PASS.


Trouble-shooting

Shared Library Paths

If you see an error similar to the following while running either the tests or the UCVM programs: 

error while loading shared libraries: libsomelib.so: cannot open shared object file: No such file or directory

This indicates that UCVM was linked against one or more shared libraries and the dynamic library loader cannot find the actual .so library at run-time. The solution is to update your LD_LIBRARY_PATH to include the directory containing the library mentioned in the error message. For example, the following command adds a new search directory to LD_LIBRARY_PATH in a csh shell: 

setenv LD_LIBRARY_PATH /home/USER/opt/somepkg/lib:${LD_LIBRARY_PATH}

Alternatively, if you do not want to work with shared libraries, UCVM can be compiled statically with the "--enable-static" configuration option.


Framework Configuration

The main package configuration file is ${UCVM_INSTALL_DIR}/conf/ucvm.conf. This is where the paths to all configured models and maps are specified, as well as any model flags are defined. The UCVM installer sets up this file automatically. Yet there are a number of situations where you will want to modify it, such as to add a new model.

The following is an example configuration: 

# UCVM config file

# UCVM model path
#
# Change to reflect UCVM installation directory.
#
ucvm_modelpath=/home/scec-00/USER/opt/aftershock/ucvm-11.9.0/model/ucvm


# Pre-defined models
#
# SCEC CVM-S
cvms_modelpath=/home/scec-00/USER/opt/aftershock/cvms/src
#
# SCEC CVM-H
cvmh_modelpath=/home/scec-00/USER/opt/aftershock/cvmh/bin
#
# USGS Bay Area high-rez and extended etrees
cencal_modelpath=/home/scec-00/USER/opt/etree/USGSBayAreaVM-08.3.0.etree
cencal_extmodelpath=/home/scec-00/USER/opt/etree/USGSBayAreaVMExt-08.3.0.etree
#
# SCEC CVM-SI
cvmsi_modelpath=/home/scec-00/USER/opt/aftershock/cvmsi/model
#
# Wasatch Front CVM
wfcvm_modelpath=/home/scec-00/USER/opt/aftershock/wfcvm/src
#
# Lin-Thurber Statewide
lin-thurber_modelpath=/home/scec-00/USER/opt/aftershock/ucvm-11.9.0/model/lin-thurber
#
# Cape Mendocino RG
cmrg_modelpath=/home/scec-00/USER/opt/aftershock/ucvm-11.9.0/model/cmrg


# User-defined models
#
# Change to reflect paths to user model files
#
# Current supported interfaces: model_etree, model_patch
#
#user1_interface=model_etree
#user1_modelpath=/home/username/model_etree/user1.etree
#user2_interface=model_patch
#user2_modelpath=/home/username/model_patch/user2.conf


# User-defined maps
#
# Change to reflect paths to user map files
#
# Current supported interfaces: map_etree
#
# Optional Yong-Wald vs30 map
yong_interface=map_etree
yong_mappath=/home/scec-00/USER/opt/aftershock/ucvm-11.9.0/model/ucvm/ucvm_yong_wald.e


# Model flags
#
#cvmh_param=USE_1D_BKG,True
#cvmh_param=USE_GTL,True


The following table describes each configuration item, where "*" indicates the model/map label. Model/map labels can be predefined strings such as "cmvh" for CVM-H, or any arbitrary string label for the case of a user-defined model.

Key Value(s) Description
ucvm_modelpath ${UCVM_INSTALL_DIR}/model/ucvm Directory containing the default projection specification and UCVM DEM/Vs30 Etree map.
*_modelpath A directory, URL, or file String identifying location of model's primary or high-rez data
*_extmodelpath A directory, URL, or file String identifying location of model's extended data (required for USGS CenCalVM extended Etree).
*_interface Models: model_etree, model_patch
Maps: model_map 		The interface code needed to parse this user-defined model/map.
*_mappath A directory, URL, or file String identifying location of user-defined map Etree
*_param Flag,Value Set a model-specific configuration Flag to Value. The defined flags are USE_1D_BKG and USE_GTL for CVM-H, for toggling the 1D background model and GTL.


Supported Standard Crustal Velocity Models

UCVM has built-in support for a number of standard community velocity models (CVMs). These standard models are referenced in ucvm_query and the API by their string labels. The following table lists the labels for these predefined CVMs. These are reserved labels and cannot be used for a user-defined model.

Note that "predefined" does not necessarily mean "installed". These are models that UCVM can query if it is linked with that model's libraries at install time. Some are pre-linked, such as lin-thurber and cmrg, the rest must be explicitly linked at install.

Label Model Type Active Limit
cvmh SCEC CVM-H External, installed separately and linked at install 1
cvms SCEC CVM-S External, installed separately and linked at install 1
cencal USGS Bay Area CenCalVM External, installed separately and linked at install 1
cvmsi SCEC CVM-SI External, installed separately and linked at install 1
wfcvm Wasatch Front CVM (Utah) External, installed separately and linked at install 1
1d Hadley-Kanamori 1D Internal, included in UCVM and automatically linked 1
lin-thurber Lin-Thurber California Statewide Internal, included in UCVM and automatically linked 1
cmrg Cape Mendocino Rob Graves Internal, included in UCVM and automatically linked 1
cmuetree CMU CVM Etree Internal, included in UCVM, user specifies etree path in ./conf/ucvm.conf 1


UCVM also defines two "model interfaces". A model interface is a specific file format convention for representing a velocity model. Any velocity model written to conform to one of these model interfaces may be easily imported and queried from UCVM. In addition, many such models may be active simultaneously, whereas only one version of a predefined model may be active at any given time. The two model interfaces are: SCEC CVM Etrees, and SCEC Patch Models. SCEC CVM Etrees employ a special schema and metadata format. SCEC Patch Models have a special conf file and binary file format. The section UCVM_User_Guide#Adding_a_User-defined_Velocity_Model discusses how to create and import these velocity models.

The currently supported model interfaces are summarized in the following table:

Interface Description Active Limit
model_etree SCEC CVM Etree 100
model_patch SCEC Patch Model 100


Supported Standard GTL Velocity Models

UCVM has built-in support for two geotechnical layer models. These near-surface models are intended to provide superior velocity information at shallow depths. The following table lists the labels for these predefined GTLs. These are reserved labels and cannot be used for a user-defined GTL.

Label GTL
elygtl Ely Vs30-derived GTL (Ely et al., 2010)
1dgtl Generic 1D, identical to 1d crustal model


Interpolation functions are used to smooth GTL material properties with the underlying crustal model material properties. This smoothing is performed over an interpolation zone along the Z axis. Interpolation functions can be assigned on a per-GTL basis. Two predefined interpolation functions are provided to the user:

Label Interpolation Function
linear Linear interpolation
ely Ely interpolation relation (Ely et al., 2010)


If the user enables a GTL model but does not specify an interpolation function, linear interpolation is used by default. If no interpolation zone is specified, a depth range of 0 m - 350m is used.


Supported Standard Maps

UCVM has built-in support for a number of standard maps for California. These standard maps contain elevation data (DEM) and Vs30 data for the region and are referenced in ucvm_query and the API by their string labels. The following table lists the labels for these predefined maps. These are reserved labels and cannot be used for a user-defined map.

Label Map
ucvm USGS NED 1 arcsec DEM, and Wills-Wald Vs30 (default)
yong USGS NED 1 arcsec DEM, and Yong-Wald Vs30


There is also a special map interface that supports reading SCEC Map Etrees. These are maps that conform to a special Etree schema and metadata format convention. The user may create their own maps in this format and import them into UCVM. Any number of maps may be defined, but only one may be active at any time. Maps are defined by the user in the UCVM configuration file (see UCVM_User_Guide#Adding_a_User-defined_Map).

The map interfaces are summarized in the following table:

Interface Description
map_etree SCEC Map Etree


Supported Model Flags

Underlying models may be configured in one of two ways: with a key/value string in the UCVM configuration file, or by passing configuration parameters with the ucvm_setparam()function. The following model flags are supported:

Parameter Value Models
USE_1D_BKG True/False (default False) CVM-H
USE_GTL True/False (default True) CVM-H


For example, to enable the 1D background model with CVM-H through the API, execute the ucvm_setparam() function as follows: 

ucvm_setparam(UCVM_PARAM_MODEL_CONF, UCVM_MODEL_CVMH, "USE_1D_BKG", "True");


Adding New Velocity Models

Enabling Another Standard Velocity Model After Installation

If after installation you wish to link in another standard velocity model, you must re-install UCVM using the process described in UCVM_User_Guide#Installation. Add the configure options appropriate for the new model you wish to link into UCVM.


Upgrading the Version of a Standard Velocity Model After Installation

Generally, UCVM must be recompiled and re-installed using the new model libraries and headers. However, if you are certain that only the model files have changed (and the query interface has NOT changed), you can simply update that model's modelpath configuration in ${UCVM_INSTALL_DIR}/conf/ucvm.conf to reference the new files.


Using Multiple Versions of a Supported Velocity Model Simultaneously

Not supported.


Adding a User-defined Velocity Model

UCVM may be extended to support any user-defined velocity model. The simplest way to add a new model is to store that model as a SCEC Etree or Patch Model, and update ${UCVM_INSTALL_DIR}/conf/ucvm.conf with the model interface and path. For example:

For SCEC Etrees: 

user1_interface=model_etree
user1_modelpath=/home/username/model_etree/user1.etree


For Patch models: 

user2_interface=model_patch
user2_modelpath=/home/username/model_patch/user2.conf


SCEC Etrees can be created with the ./bin/ucvm2etree utility. Patch models can be created with the ./bin/patchmodel utility.


For other models that either are represented by tables, or have their own native API, UCVM may be extended to query from these models. However, this requires code modifications to the core UCVM library located in ./src/ucvm and recompilation. The general steps are:

  • Define new model label UCVM_MODEL_MODELNAME in ucvm_dtypes.h
  • Create ucvm_model_modelname.h/.c containing the glue code that links the UCVM query interface to the native model interface
  • Modify ./src/ucvm/ucvm.c:
    • Add ucvm_model_modelname.h include at top
    • Add model lookup to ucvm_add_model() function
  • Modify ./src/ucvm/Makefile.am:
    • Add ucvm_model_modelname.o to list of libucvm.a dependencies
  • Reconf Makefiles with ./scripts/autoconf/reconf.sh
  • Recompile UCVM, passing the following options to configure:
    • Path to the native model header files with: CFLAGS='-I<hdr_path>'
    • Path to the native model library files with: LDFLAGS='-L<lib_path> -l<libname>"


Adding a User-defined Map

Update ${UCVM_INSTALL_DIR}/conf/ucvm.conf with the map interface and Etree path: 

usermap1_interface=map_etree
usermap2_mappath=/home/username/maps/usermap1.e

User-defined maps can be created with the ./bin/grd2etree utility.


Framework Description

Concept of Operation

Combining Velocity Models into a Composite Model

UCVM combines multiple regional velocity models, along with a DEM map and a Vs30 map, into one composite model for the purposes of querying surface elevation, Vs30, Vp, Vs, and density. Individual model setup and query details are abstracted under a uniform interface, and the application sees only the composite model. This simplifies application code and makes it easier for those programs to support new velocity models in the future.

UCVM model tiling method.

Velocity models are combined into the composite by tiling them on top of one another. When UCVM is initialized, the user selects an ordered list of models to query for data. Query points are then submitted to each velocity model in that list, one model at a time in list order. The first model to return valid velocity data for the point is considered to have fullfilled that data request and subsequent models are not queried. Generally, no smoothing is performed at the interfaces between models (an exception is interpolation between a GTL and crustal model as described below). For each query point, the following data is returned: surface elevation, Vs30, Vp, Vs, and density. The figure at right illustrates how this tiling is performed.

Regional models may include: CVM-H, CVM-H, USGS Bay Area, 1D, or other user-defined models. Most models and maps have a maximum extent, outside of which no data is available. The exception is the generic 1D model as it has infinite extents. Applications must check the returned velocity and density values to ensure they are valid.


Querying with one or more GTLs

The API distinguishes between two types of regional velocity models: GTL models, and crustal models. GTL models are shallow near-surface velocity models called geotechnical layers. Crustal models are deeper velocity models such as tomographic models. When a user selects to query from one or more crustal models only, the API executes the previously described behavior. However, if one or more GTL models are selected, additional processing is performed.

When a GTL model is given in the ordered list of models, the API creates a default interpolation zone along the z-axis over which interpolation between this GTL and the underlying crustal models is performed. It also assigns a default (linear) interpolation function to smooth the velocities of the GTL and underlying crustal models. Both the interpolation zone and interpolation function can be changed by the user.

Querying for a point in this operating mode is now slightly different from the previous crustal-only case. As before, all query points are submitted to the crustal models in the ordered list of models (skipping any GTLs). However, the z coordinate of the points may be shifted down to the lower edge of the interpolation zone if the point falls within it. The crustal models are queried with this possibly modified 3D coordinate and the velocities/density values are saved. The same list of query points is then submitted to the GTL models in the ordered list of models (skipping any crustals) and the z coordinate of those points within the interpolation zone may be shifted up to the top edge. The GTL models are queried with this possibly modified 3D coordinate and the velocity/density values are saved.

The list of query points is then traversed one final time. Those points that fall above the interpolation zone will have their velocities/densities set to those of the GTL as processed by the interpolation function assigned to that GTL. Those points that fall within the interpolation zone and have valid GTL/crustal values will have their GTL/crustal values smoothed according to the assigned interpolation function. Points that fall below the interpolation zone and have valid crustal values will have their velocities/densities set to the crustal values. Note that points with invalid/incompatible velocities in either the GTL or crustal dataset cannot be smoothed and the interpolation results will be marked as invalid.


Querying Models Via Native Interface versus Querying UCVM

For the most part, querying any model through its native interface will yield the same material properties as UCVM. There are a few exceptions, which are noted here:

  • When querying by elevation with CVM-H and any GTL, points that fall above the UCVM free surface and within the CVM-H domain are normalized to be relative to the CVM-H free surface. This is done to eliminate small discrepancies between the UCVM DEM and the CVM-H DEM.
  • The same correction is performed when querying by elevation with CenCalVM and any GTL.
  • When querying CenCalVM by depth, UCVM does not directly pass that point to the cencalvm interface since the definition of depth differs between UCVM and cencalvm. Instead, UCVM derives the elevation of the free surface (ground/air, ground/water) at the point of interest by drilling down through the model at that point and finding the highest octant with valid material properties. UCVM then converts the query point depth to elevation and queries cencalvm by elevation.


Utilities

ucvm_query

This is the command-line tool for querying CVMs. Any set of crustal and GTL velocity models may be selected and queried in order of preference. Points may be queried by (lon,lat,dep) or (lon,lat,elev) and the coordinate conversions for a particular model are handled transparently. 

Usage: ucvm_query [-m models<:ifunc>] [-p user_map] [-c coordtype] [-f config] [-z zmin,zmax] < file.in

Flags:
        -h This help message.
        -m Comma delimited list of crustal/GTL models to query in order
           of preference. GTL models may optionally be suffixed with ':ifunc'
           to specify interpolation function.
        -p User-defined map to use for elevation and vs30 data.
        -c Z coordinate mode: geo-depth (gd, default), geo-elev (ge).
        -f Configuration file. Default is ./ucvm.conf.
        -z Optional depth range for gtl/crust interpolation.

Input format is:
        lon lat Z

Output format is:
        lon lat Z surf vs30 crustal cr_vp cr_vs cr_rho gtl gtl_vp gtl_vs gtl_rho cmb_algo cmb_vp cmb_vs cmb_rho

Notes:
        - If running interactively, type Cntl-D to end input coord list.

Version: 11.9.0

The config file is generally ${UCVM_INSTALL_DIR}/conf/ucvm.conf, but you may pass in any custom configuration file.


ucvm2etree

This utility creates a SCEC-formatted CVM Etree extracted from a set of CVMs. The CVM Etree may then be imported into UCVM and queried like any other velocity model. This confers a number of advantages:

  • Several different velocity models can be combined into one composite model and distributed as a single file.
  • Any number of CVM Etrees can be easily imported into UCVM without recompilation (just a config change) since Etree support is built in.
  • The Etree data structure is efficient and the library provides disk caching and buffering, resulting in very fast query performance.

How to use ucvm2etree: 

Usage: ucvm2etree [-h] -f config

Flags:
        -f: Configuration file
        -h: Help message

Version: 11.9.0


The following is an example ucvm2etree configuration file. It can also be found in ${UCVM_INSTALL_DIR}/conf/example/ucvm2etree_example.conf: 

# ucvm2etree conf file

# Projection and region coordinates (degrees):
proj=+proj=aeqd +lat_0=36.0 +lon_0=-120.0 +x_0=0.0 +y_0=0.0
lon_0=-129.75
lat_0=40.75
rot=55.0

# Domain dimensions (meters):
x-size=1800000.0
y-size=900000.0
z-size=112500.0

# Blocks partition parameters:
nx=32
ny=16

# Max freq (Hz), points per wavelength
max_freq=0.5
ppwl=4.0

# Etree max cellsize to allow in meters
max_cellsize=10000.0

# Etree parameters and info
title=Cal0.5Hz200ms
author=P_Small
date=05/2011
outputfile=./ucvm_cvmh_cal_0.5hz_200ms.e
format=etree

# CVMs to use
cvm=cvmh
ucvmconf=../../conf/aftershock/ucvm.conf

# Min Vs, Vp
vs_min=200.0

# Scratch
scratch=/tmp


Import the new CVM Etree into UCVM by adding these lines to ${UCVM_INSTALL_DIR}/conf/ucvm.conf: 

 newmodel_interface=model_etree
 newmodel_modelpath=config.outputfile

 where:
   newmodel          : name for your new model
   config.outputfile : outputfile from config passed into ucvm2etree


grd_query

This command-line tool queries data from a set of ArcGIS grid files in GridFloat format. 

Usage: grd_query [-e] [-v] -d datadir [-b bkgdir] < file.in

Flags:
        -e Employ GRD bathymetry heuristic.
        -v Employ GRD vs30 heuristic.
        -d Main ArcGIS Gridfloat data directory. Default is ./ned.
        -b Background/Bathymetry data directory. Default is ./bath.
        -h This help message.

Input format is:
        lon lat

Output format is:
        lon lat val valid

Notes:
        - If running interactively, type Cntl-D to end input coord list.

Version: 11.9.0


grd2etree

This utility extracts a SCEC-formatted Etree map from a set of DEM and Vs30 grid files in ArcGIS Gridfloat format. 

Usage: grd2etree [-h] -f config

Flags:
        -f: Configuration file
        -h: Help message

Version: 11.9.0


The following is an example grd2etree configuration file. It can also be found in ${UCVM_INSTALL_DIR}/conf/example/grd2etree_example.conf: 

# grd2etree UCM Map config file

# Domain corners coordinates (degrees):
proj=+proj=aeqd +lat_0=36.0 +lon_0=-120.0 +x_0=0.0 +y_0=0.0
lon_0=-129.75
lat_0=40.75
rot=55.0

# Domain dimensions (meters):
x-size=1800000.0
y-size=900000.0

# Spacing
spacing=250.0

# Etree parameters and info
title=UCVM_Elev_Vs30_Map_Wills_Wald
author=P_Small
date=05/2011
outputfile=../../model/ucvm/ucvm.e

# Grid data directories
elev_hr_dir=/home/scec-00/USER/opt/ned
elev_lr_dir=/home/scec-00/USER/opt/bath
vs30_hr_dir=/home/scec-00/USER/opt/vs30/wills_gridfloat
vs30_lr_dir=/home/scec-00/USER/opt/vs30/wald_gridfloat


Import the new Etree Map into UCVM by adding these lines to ${UCVM_INSTALL_DIR}/conf/ucvm.conf: 

 newmodel_interface=map_etree
 newmodel_modelpath=config.outputfile

 where:
   newmodel          : name for your new model
   config.outputfile : outputfile from config passed into grd2etree


patchmodel

The utility provides a post-processing "patching" mechanism to smooth out discontinuities at the interfaces between different regional models. The user identifies a 3D geographic region in the form of an open box where smoothing is to be performed. The patchmodel program is run to extract the material properties along the vertical surfaces of this box at a fixed resolution (eg: 250 m) from 0m depth to "z-size" depth and it saves them into a new model which may then be imported into and queried by UCVM. Points that fall within the smoothing region are interpolated using an inverse distance weighting function with the 10% closest surface points on the same z-plane. A power factor of 2.0 is used for weighting. Linear interpolation is used along the z-axis to smooth out the edge values. 

Usage: patchmodel [-h] -f config

Flags:
        -f: Configuration file
        -h: Help message

Version: 11.9.0


The following is an example patchmodel configuration file. It can also be found in ${UCVM_INSTALL_DIR}/conf/example/patch_example.conf: 

# Example Patchmodel config file

# Version
version=cvmh_p1_2011/05/24

# UCVM config
ucvmstr=cencal,cvmh,lin-thurber,1d
ucvm_interp_zrange=0.0,350.0
ucvmconf=../../conf/aftershock/ucvm.conf

# Projection
proj=+proj=aeqd +lat_0=36.0 +lon_0=-120.0 +x_0=0.0 +y_0=0.0
lon_0=-121.3
lat_0=35.6
rot=90.0

# Domain dimensions (meters):
x-size=550000.0
y-size=50000.0
z-size=112500.0

# Spacing (meters)
spacing=250.0

# Output paths
modelname=cvmh_p1
modelpath=/home/scec-00/USER/opt/aftershock/ucvm/model/patch


Import the new patch into UCVM by adding these lines to ${UCVM_INSTALL_DIR}/conf/ucvm.conf: 

 newmodel_interface=model_patch
 newmodel_modelpath=config.modelpath/config.modelname.conf

 where:
   newmodel         : name for your new model
   config.modelpath : modelpath from config passed into patchmodel
   config.modelname : modelname from config passed into patchmodel

 Note: Be sure to append ".conf" to newmodel_modelpath


ecompact

This optimization utility compacts an etree file with any payload and schema. It does this by removing empty space in the Etree data structure. 

Usage: ecompact in_etree out_etree


ecoalesce

This optimization utility coalesces an etree file that conforms to either the SCEC CVM Etree or CMU CVM Etree conventions. It does this by replacing eight adjacent octants with identical material properties at level N with a single octant containing the same material properties at level N-1. 

Usage: ecoalesce in_etree out_etree


C Application Programming Interface

UCVM provides a programming interface for querying Vp, Vs, and rho from any user-defined model. The main UCVM interface is as follows: 

#ifndef UCVM_H
#define UCVM_H

#include <stdarg.h>
#include "ucvm_dtypes.h"

/* Initializer */
int ucvm_init(const char *config);

/* Finalizer */
int ucvm_finalize();

/* Enable specific model(s), by string list, by label, or 
   by ucvm_model_t */
int ucvm_add_model_list(const char *list);
int ucvm_add_model(const char *label);
int ucvm_add_user_model(ucvm_model_t *m, ucvm_modelconf_t *conf);

/* Use specific map (elev, vs30) by label */
int ucvm_use_map(const char *label);

/* Associate specific interp func with GTL model, by label 
   or by ucvm_ifunc_t */
int ucvm_assoc_ifunc(const char *mlabel, const char *ilabel);
int ucvm_assoc_user_ifunc(const char *mlabel, ucvm_ifunc_t *ifunc);

/* Get label for a model */
int ucvm_model_label(int m, char *label, int len);

/* Get label for an interpolation function */
int ucvm_ifunc_label(int f, char *label, int len);

/* Get version for a model */
int ucvm_model_version(int m, char *ver, int len);

/* Set parameters (see ucvm_dtypes.h for valid param flags) */
int ucvm_setparam(ucvm_param_t param, ...);

/* Query underlying models */
int ucvm_query(int n, ucvm_point_t *pnt, ucvm_data_t *data);

/* Get info on installed models */
int ucvm_install_info(char *info, int len);

#endif

The general order of operations for using this interface is:

  • Initialization (ucvm_init())
  • Add models in order of preference using ucvm_add_model(). These may be either crustal or GTL models. See below for specific details.
  • Set any models-specific flags using ucvm_setparam. These will override any flags specified in ucvm.conf.
  • If GTLs have been added:
    • Associate an interpolation function with each using ucvm_assoc_ifunc(). Otherwise, linear interpolation will be used.
    • Set an interpolation depth range using ucvm_setparam(UCVM_PARAM_IFUNC_ZRANGE, ...). Otherwise the interpolation range is set to 0,0.
  • Query points of interest with ucvm_query()
  • Finalization (ucvm_finalize())


Notes on enabling models:

  • Models are referenced either by a pre-defined string id or by a populated ucvm_model_t structure.
  • Multiple models may be registered, and they are queried in order of registration.
  • A helper function ucvm_add_model_list() is provided to quickly add multiple models. The string format is "gtl_model<:gtl_interp>,crustal_model,..." where "<:gtl_interp>" is an optional GTL interpolation function specification. For example, the string "elygtl:ely,cvmh" specifies the Ely GTL and CVM-H, adn the use of the Ely interpolation function to smooth between the GTL and crustal models.
  • Pre-defined models include: CVM-S, CVM-H, CenCal, Lin-Thurber, Rob Graves Cape Mendocino, 1D, Ely GTL, any SCEC Etree or patch listed in the UCVM configuration file. These models are enabled by calling ucvm_add_model() with their name string identifier as listed in either ucvm_dtypes.h (pre-defined) or in the UCVM configuration file (user-defined SCEC Etree, UCVM patch).
  • Most predefined model interfaces only support one model instance at a time. However, multiple Etrees and patches may be enabled. Etrees and patches are defined in the UCVM configuration file with the following commands:
# Etree definition and path to etree
usermodel1_interface=model_etree
usermodel1_modelpath=/home/...

# Patch definition and path to configuration file
usermodel2_interface=model_patch
usermodel2_modelpath=/home/...

where:
usermodel1/usermodel2 : replaced with desired string identifier for the etree/patch model
  • The programmer may also define their own models and integrate them into UCVM. A user model interface is defined by creating the init(), finalize(), getversion(), getlabel(), setparam(), and query() functions for the model interface, and populating the ucvm_model_t structure with these function pointers and some additional record keeping information. Configuration information for a specific model instance of that interface is placed in a ucvm_modelconf_t structure. Once a model is fully described with a ucvm_model_t interface and a ucvm_modelconf_t configuration, it can be registered for use with the ucvm_add_user_model() function and queried with the ucvm_query() function.


Data Type Descriptions

The full list of defined data types are listed in /include/ucvm_dtypes.h. The following is a general description of the useful application definitions:

Points are specified with a ucvm_point_t structure: 

/* 3D point */
typedef struct ucvm_point_t 
{
  double coord[3];
} ucvm_point_t;


Return data is specified with a ucvm_data_t structure: 

typedef struct ucvm_data_t 
{
  double surf; /* Elevation of free surface in meters */
  double vs30; /* Vs30 value in m/s */
  ucvm_domain_t domain;  /* Domain where the point lies: GTL model, interpolation zone, crustal model, none. */
  double shift_cr; /* Depth shift applied to point when querying crustal models. Only used when a GTL is enabled. */
  double shift_gtl; /* Depth shift applied to point when querying GTL models. Only used when a GTL is enabled. */
  ucvm_prop_t crust; /* Material properties from crustal model */
  ucvm_prop_t gtl; /* Material properties from GTL model */
  ucvm_prop_t cmb; /* Combined GTL/crustal material properties. This is the final property set that applications should reference. */
} ucvm_data_t;

where ucvm_prop_t is:

/* Material properties */
typedef struct ucvm_prop_t 
{
  int source; /* Model idenfitifer */
  double vp; /* Velocity in m/s */
  double vs; /* Velocity in m/s */
  double rho; /* Density in g/m^3 */
} ucvm_prop_t;


Model interfaces (both crustal and GTL) are defined with a ucvm_model_t structure: 

/* Model */
typedef struct ucvm_model_t 
{
  ucvm_mtype_t mtype;
  int (*init)(int id, ucvm_region_t *r, const char *config);
  int (*finalize)();
  int (*getversion)(int id, char *ver, int len);
  int (*getlabel)(int id, char *ver, int len);
  int (*setparam)(int id, int param, ...);
  int (*query)(int id, ucvm_ctype_t cmode,
               int n, ucvm_point_t *pnt, 
               ucvm_data_t *data);
} ucvm_model_t;


Other Interfaces

2D Grid Interface

Provides an interface for generating 2D regular grids in any USGS map projection. Include the header "ucvm_grid.h" to use these functions. 

/* Generate grid from projection and dimensions */
int ucvm_grid_gen(ucvm_proj_t *iproj, ucvm_trans_t *trans,
                  ucvm_proj_t *oproj,
                  ucvm_dim_t *dims, double spacing, 
                  ucvm_point_t *pnts);

/* Generate grid from projection and dimensions */
int ucvm_grid_gen_file(ucvm_proj_t *iproj, ucvm_trans_t *trans,
                       ucvm_proj_t *oproj,
                       ucvm_dim_t *dims, double spacing, 
                       const char *filename);

/* Convert point list from one projection to another */
int ucvm_grid_convert(ucvm_proj_t *iproj, 
                      ucvm_proj_t *oproj, 
                      size_t n, ucvm_point_t *pnts);

/* Convert point list from one projection to another */
int ucvm_grid_convert_file(ucvm_proj_t *iproj, 
                           ucvm_proj_t *oproj, 
                           size_t n, const char *filename);


Extracting Values from UCVM

Two methods are provided for extracting material properties from UCVM: command-line tools, and a C API. These are described in the sections below. The following table summarizes the model features supported by each interface:


Extracting Values on the Command Line

The ucvm_query utility is provided for querying a set of community velocity models. Points may either be input interactively or via a text file, and can be either (lon, lat, elevation) or (lon, lat, depth).

The following output shows an interactive example on three points (followed by a Cntl-D to terminate input) using the CVM-S model. Starting in the UCVM installation directory, enter these commands: 

% cd bin
% ./ucvm_query -m cvms -f ../conf/ucvm.conf
Using Geo Depth coordinates as default mode.
-118.0 34.0 0.0
-118.0 34.0 100.0
-118.0 34.0 1000.0 <Cntrl-D>
 -118.0000    34.0000      0.000    295.679    390.000       cvms    696.491    213.000   1974.976       none      0.000      0.000      0.000      crust    696.491    213.000   1974.976
 -118.0000    34.0000    100.000    295.679    390.000       cvms   1683.174    603.470   2130.773       none      0.000      0.000      0.000      crust   1683.174    603.470   2130.773
 -118.0000    34.0000   1000.000    295.679    390.000       cvms   3660.809   2056.628   2443.042       none      0.000      0.000      0.000      crust   3660.809   2056.628   2443.042

Similarly, here is an example for the CVM-H model: 

% cd bin
% ./ucvm_query -m cvmh -f ../conf/ucvm.conf
Using Geo Depth coordinates as default mode.
-118.0 34.0 0.0
-118.0 34.0 100.0
-118.0 34.0 1000.0 <Cntrl-D>
 -118.0000    34.0000      0.000    295.679    390.000       cvmh    824.177    195.000   1084.062       none      0.000      0.000      0.000      crust    824.177    195.000   1084.062
 -118.0000    34.0000    100.000    295.679    390.000       cvmh   2371.500    727.748   2051.320       none      0.000      0.000      0.000      crust   2371.500    727.748   2051.320
 -118.0000    34.0000   1000.000    295.679    390.000       cvmh   2616.063   1082.813   2127.783       none      0.000      0.000      0.000      crust   2616.063   1082.813   2127.783


Additional Examples

The following example directs ucvm_query to query the Ely GTL and CVM-S crustal model by depth, using the Ely interpolation function to smooth the values. The Z-axis interpolation zone is set to 0-400m. 

% ./ucvm_query -m elygtl:ely,cvms -c gd -z 0.0,400.0 -f ../conf/ucvm.conf


The following example queries the USGS Bay Area (CenCalVM) and CVM-H models by elevation, tiling them into a composite model (where CenCalVM has priority). 

% ./ucvm_query -m cencal,cvmh -c ge -f ../conf/ucvm.conf


The following example queries the 1D model by depth, with surface elevation and Vs30 values taken from the alternate Yong-Wald Vs30 map. 

% ./ucvm_query -m 1d -p yong -c gd -f ../conf/ucvm.conf


Extracting Values in a C Program

Working code examples that use the UCVM A API can be found in the directory ${UCVM_INSTALL_DIR}/examples. Feel free to use these examples as a basis for your own programs. In general, using the API in your program requires the following source/Makefile updates.

Include the ucvm.h header in your source code at a minimum. Eg: 

#include "ucvm.h"


Set the include path to the location of the UCVM headers, the Etree and Proj.4 headers, and all of the standard model include paths. Eg, for GNU C compiler and CVM-S: 

CFLAGS = $(CFLAGS) -I$(UCVM_INSTALL_DIR)/include  -I$(CVMS_INSTALL_DIR)/include -I$(ETREE_INSTALL_DIR)/libsrc -I$(PROJ4_INSTALL_DIR)/include


Identify the library paths and names to UCVM static library, the Etree and Proj.4 libraries, and all of the standard model library paths needed by your application to the linker. Depending on platform, also include the pthreads and math libraries. Eg, for GNU linker and CVM-S (note the use of the gfortran lib since CVM-S is Fortran): 

LDFLAGS = $(LDFLAGS) -L$(UCVM_INSTALL_DIR)/lib ucvm -L($CVMS_INSTALL_DIR)/lib cvms -L$(ETREE_INSTALL_DIR)/libsrc etree -L$(PROJ4_INSTALL_DIR)/lib proj 
          -lgfortran -pthreads -lm


Example Programs

Please see the ./examples directory of the software distribution for compiled examples that employ the C API.


History of UCVM Releases

Acknowledgements and Contact Info

Support for the development and maintenance of the UCVM framework has been provided by the Southern California Earthquake Center (SCEC). SCEC is funded by NSF Cooperative Agreement EAR-0106924 and USGS Cooperative Agreement 02HQAG0008.

Contributions to this manual were made by: Patrick Small, and Philip Maechling.

Please email software@scec.org for help on downloading and using UCVM, and for any suggestions for the delivery of the code or for this manual.

Please reference at least Small et al (2011) if you use this software framework; other references should be considered, depending on the purpose.


Technical Notes

SCEC CVM Etree Convention

Etree Model Format

  • Variable resolution based off of Vs, max supported frequency, and points per wavelength. The resolution at any particular region will be dependent upon the local Vs value (relation shown below). However, a minimum Vs at Etree creation will clamp the resolution to a maximum value regardless of how low the local Vs is found to be.
rez = vs / (ppwl * freq)

where:
vs: Vs at point of interest (m/s)
ppwl: points per wavelength
freq: max supported frequency (Hz)
  • Model data is referenced relative to free surface. Free surface is defined at air/ground, water/ground interface. UCVM topography and bathymetry can be used to determine if a point is in the air/water and default properties returned for those domains.
  • Stored properties are Vp, Vs, and density.


Etree Metadata Description

The Etree metadata tag describes the payload of the octants, the extents of the coverage region, and the map projection. It will have the following format, with fields delimited by vertical bars: 

metatype_version|title|author|date|vs_min|max_freq|ppwl|format|proj.4_string|geo_origin|rot_angle|xyz_dims|xyz_ticks

where:
  metatype_version: "SCEC_CVM_V1" string of max length 64 chars
  title: free-format title string of max length 64 chars
  author: free-format author string of max length 64 chars
  date: YY/MM/DD date string
  vs_min: vs minimum used to determine max resolution
  max_freq: maximum supported frequency in Hz
  ppwl: Points per wavelength
  format: data format specification of octants. Uses string format: "name,data_type,size,units". eg: "vp,float,4,m/s;vs,float,4,m/s;rho,float,4,kg/m^3"
  proj.4_string: Proj.4 projection string, eg: "+proj=aeqd +lat_0=36.0 +lon_0=-120.0 +x_0=0.0 +y_0=0.0"
  geo_origin: Origin point of CVM region in geo coordinates, eg: "-129.25,41.0"
  rot_angle: Rotation angle of bounding box in degrees, eg "55.0"
  xyz_dims: Dimensions of bounding box in km, eg "1800,800,100"
  xyz_ticks: Number of ticks along each dimension


SCEC Patch Model Format

A patch model consists of five files: a configuration text file, and four binary files with the surface data. All of these files are automatically generated by the patchmodel utility. The sections below describe the file formats.


Configuration file

The patch model configuration file specifies the origin, dimensions, and map projection of the 3D region covered by the patch. An example follows: 

# cvmh patch conf file

# Version
version=cvmh_p1_2011/05/24
# Projection
proj=+proj=aeqd +lat_0=36.0 +lon_0=-120.0 +x_0=0.0 +y_0=0.0
lon_0=-121.300000
lat_0=35.600000
rot=90.000000
# Spacing
spacing=250.000000
# Dimensions
x-size=550000.000000
y-size=50000.000000
z-size=112500.000000
# Paths to surface files
surf_0_0_path=/home/scec-00/USER/opt/aftershock/ucvm/model/patch/cvmh_p1_surf_0_0.bin
surf_1_0_path=/home/scec-00/USER/opt/aftershock/ucvm/model/patch/cvmh_p1_surf_1_0.bin
surf_0_1_path=/home/scec-00/USER/opt/aftershock/ucvm/model/patch/cvmh_p1_surf_0_1.bin
surf_1_1_path=/home/scec-00/USER/opt/aftershock/ucvm/model/patch/cvmh_p1_surf_1_1.bin


Surface Files

The surface file format is a 2D array of three floating point values: vp, vs, and density. The assignment of x versus y axis in each file is dependent on the orientation of the surface with respect to the box's origin point.


SCEC Map Etree Convention

Etree Model Format

  • 3D Etree with a single octant depth along Z-axis (effectively a 2D grid)
  • Fixed resolution based off of maximum desired grid spacing in grd2etree configuration.
  • Sampled with grid registration to allow smoothing of adjacent octants in UCVM.
  • Stored values at each grid point are: surface elevation (float), Vs30 (float).


Etree Metadata Description

The Etree metadata tag describes the payload of the octants, the extents of the coverage region, and the map projection. It will have the following format, with fields delimited by vertical bars: 

metatype_version|title|author|date|spacing|format|proj.4_string|geo_origin|rot_angle|xy_dims|xyz_ticks

where:
  metatype_version: "SCEC_MAP_V1" string of max length 64 chars
  title: free-format title string of max length 64 chars
  author: free-format author string of max length 64 chars
  date: YY/MM/DD date string
  spacing: grid spacing in meters
  format: data format specification of octants. Uses string format: "name,data_type,size,units". eg: "surf,float,4,m/s;vs30,float,4,m/s;"
  proj.4_string: Proj.4 projection string, eg: "+proj=aeqd +lat_0=36.0 +lon_0=-120.0 +x_0=0.0 +y_0=0.0"
  geo_origin: Origin point of CVM region in geo coordinates, eg: "-129.25,41.0"
  rot_angle: Rotation angle of bounding box in degrees, eg "55.0"
  xy_dims: Dimensions of bounding box in km, eg "1800,800"
  xyz_ticks: Number of ticks along each dimension


References

  1. Ely, G., T. H. Jordan, P. Small, P. J. Maechling (2010), A Vs30-derived Near-surface Seismic Velocity Model Abstract S51A-1907, presented at 2010 Fall Meeting, AGU, San Francisco, Calif., 13-17 Dec. [Ely2010-AGU.pdf]
  2. Graves, R. (1994), Rupture History and Strong Motion Modeling of the 1992 Cape Mendocino Earthquake, USGS External Grant Report Cape mendocino-19941027.pdf
  3. Lin, G., C. H. Thurber, H. Zhang, E. Hauksson, P. Shearer, F. Waldhauser, T. M. Brocher, and J. Hardebeck (2010), A California statewide three-dimensional seismic velocity model from both absolute and differential Times, Bull. Seism. Soc. Am., 100, in press. supplemental
  4. Small, P., P. Maechling, T. Jordan, G. Ely, and R. Taborda (2011), SCEC UCVM - Unified California Velocity Model, in 2011 Southern California Earthquake Center Annual Meeting, Proceedings and Abstracts, vol. TBD, p. TBD.
  5. Taborda R., López J., O'Hallaron D., Tu T. and Bielak J. (2007), A review of the current approach to CVM-Etrees, SCEC Annual Meeting, Palm Springs, CA, USA, September 8–12. [1]
  6. Wald, D. J., and T. I. Allen (2007), Topographic slope as a proxy for seismic site conditions and amplification, Bull. Seism. Soc. Am., 97 (5), 1379-1395, doi:10.1785/0120060267.
  7. Wills, C. J., and K. B. Clahan (2006), Developing a map of geologically defined site-condition categories for California, Bull. Seism. Soc. Am., 96 (4A), 1483-1501, doi:10.1785/0120050179.
  8. Yong, A., Hough, S.E., Iwahashi, J., and A. Braverman (2012), A terrain-based site conditions map of California with implications for the contiguous United States, Bull. Seism. Soc. Am., accepted.


License and Disclaimer

License

Copyright (c)2011 Southern California Earthquake Center (SCEC) and the University of Southern California (USC). This copyright applies to the UCVM codebase as a whole, or any individual distributed applications. The individual contributions of government employees, which may be identified on a per-file basis using Subversion (SVN) (see developer site), are in the public domain.

The software and content provided on this website are made available under the terms of the Apache License, Version 2.0. A copy of the License is provided by the Apache Software Foundation (http://www.apache.org/licenses/LICENSE-2.0).

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.


Disclaimer

THIS SOFTWARE AVAILABLE ON THE UCVM WEBSITE IS PROVIDED "AS IS" AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE SOUTHERN CALIFORNIA EARTHQUAKE CENTER (SCEC), THE UNIVERSITY OF SOUTHERN CALIFORNIA (USC), OR ANY OF THEIR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


Without limiting the foregoing, SCEC and USC make no warranty that:

1. The software will meet your requirements.

2. The software will be uninterrupted, timely, secure or error-free.

3. The results that may be obtained from the use of the software will be effective, accurate or reliable.

4. The quality of the software will meet your expectations.

5. Any errors in the software obtained from the UCVM web site will be corrected.


Software and its documentation made available on the UCVM web site:

6. Could include technical or other mistakes, inaccuracies or typographical errors. UCVM contributors may make changes to the software or documentation made available on its web site.

7. May be out of date and SCEC, its contributors, and USC make no commitment to update such materials.


SCEC, its contributors, and USC assume no responsibility for errors or omissions in the software or documentation available from the UCVM web site.

In no event shall SCEC, its contributors, or USC be liable to you or any third parties for any special, punitive, incidental, indirect or consequential damages of any kind, or any damages whatsoever, including, without limitation, those resulting from loss of use, data or profits, whether or not SCEC, its contributors, or USC has been advised of the possibility of such damages, and on any theory of liability, arising out of or in connection with the use of this software.

The use of the software downloaded through the UCVM site is done at your own discretion and risk and with agreement that you will be solely responsible for any damage to your computer system or loss of data that results from such activities. No advice or information, whether oral or written, obtained by you from SCEC, the UCVM website, its contributors, or USC shall create any warranty for the software.

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