Registered CVMs

meihuisu edited this page Jun 26, 2018 · 41 revisions

Model Names and Abbreviations

CVM names and naming conventions within UCVM can be confusing, largely because the CVM model names and abbreviations have changed during UCVM development, and there is not consistent use throughout the software and documentation.

UCVM users need to know the velocity model of interest, and then the abbreviation that UCVM uses to refer to the CVM of interest. The following tables briefly describes the standard CVM models available through UCVM, and the abbreviation used by the UCVM software to refer to each model.

Model Name Description UCVM Abbreviation
CVM-H Southern California Velocity Model developed by Harvard Structural Geology Group with optional geotechnical layer cvmh
CVM-S4 Southern California Velocity Model developed by SCEC, Caltech, USGS Group with geotechnical layer cvms
CVM-S4.26 Tomography improved version of CVM-S4 with no geotechnical layer but has an optional Ely-Jordan GTL cvms5
CVM-S4.26.M01 CVM-S4.26 with added geotechnical layer cvmsi
USGS Bay Area USGS developed San Francisco and Central California velocity model cencal
CCA06 Central California Area Velocity Model at iteration 6 with added optional Ely-Jordan GTL (UCVMC18.5) cca
CS17.3 CyberShake Study 17.3 Central California Velocity Model with added optional Ely-Jordan GTL (UCVMC18.5) cs173
CS17.3-H CyberShake Study 17.3 Central California Velocity Model integrated with Harvard group's Santa Maria and San Joaquin Basin Models with added optional Ely-Jordan GTL (UCVMC18.5) cs173h
Modified Hadley Kanamori 1D Southern California regional 1D model based on Hadley-Kanamori model 1d
Northridge Region 1D Los Angeles Region 1D model used in SCEC Broadband Platform bbp1d

This table shows the standard scientific name for each model (on the left), and the model abbreviations used by UCVM in column 2. It is the abbreviation listed in column 2 that is used to specify the model of interest when calling UCVM. The sections below describe each of these registered models.

Map Regions

Coverage Regions for registered CVMs. Map shows coverage region for California CVMs registered into UCVMC. Coverage region for UCVM 2D maps (cyan) overlayed upon regions of various California 3D velocity models (CVM-S4: red, CVM-S4 geotechnical regions: Red Polygons, CVM-H high resolution: small blue, CVM-H low resolution: larger blue, USGS High Resolution Bay Area: small white, USGS Low Resolution Bay Area: larger white)

CVM registration

We call the process of adding a CVM model (or other models, like topography models) registering a model in UCVM. Certain model information is required in order to register a model into UCVM. This includes, the geographical coverage region, the native projection, the material properties the model returns, and whether topography is supported in the model. In some cases, other information such as interpolation method is specified.

Model Configuration

UCVMC defines a configuration file for each registered model. The model configuration files are collected in the installation directory in UCVMC/model/model_abbreviation/model_name.conf (e.g. UCVMC/model/1d/1d.conf)

Users can examine these .conf files to determine basic information about a model. In most cases, these model configuration files are static, and should not be modified by the user. In a few cases, such as bbp1d.conf file, there are user configuration options in the bbp1d.conf file (specifically a flag to specify whether the model should be delivered with interpolation).

Hadley-Kanamori 1D Model

The UCVM default background model is a modified Hadley-Kanamori 1d model. By default, ucvmc delivers this model using linear interpolation between layers. However, users can edit the 1d/1d.conf file and set the interpolation flag off, in which case the model will be delivered as a series of layers, with no interpolation of material property values between layers.

    # 1D Velocity Model configuration
    #
    # Vp is interpolated between layer n to n+1.
    # Rho is derived from vp (./src/ucvm/ucvm_model_1d.c)
    # Vs is derived from Vp and Rho (./src/ucvm/ucvm_model_1d.c)
    #
    version=Hadley-Kanamori 1D (CVM-S)
    # Depth of model in layers
    num_z=9
    # Depth to start of layer (km)
    depth_vals=1.0, 5.0, 6.0, 10.0, 15.5, 16.5, 22.0, 31.0, 33.0
    # Vp at start of layer (km/s)
   vp_vals=5.0, 5.5, 6.3, 6.3, 6.4, 6.7, 6.75, 6.8, 7.8

This model definition only gives Vp values. Vs and rho are scaled from this Vp. The rules UCVMC uses to produce the Vs, and rho values are giving in the ../src/ucvm/ucvm_model_1d.c files mentioned in this configuration file.

An table from the original Hadley Kanamori paper, giving the original HK 1D model definition is posted on a SCEC website: Hadley Kanamori 1D model description

BBP1D LA Basin 1D Model

The BBP1D model was originally constructed by R. Graves as a 1d model for the Northridge Region. It was developed by averaging velocity profiles from a series of site around the Los Angeles basin. The resulting model is used in the SCEC Broadband Platform when simulating regional Los Angeles area earthquakes. This model configuration file provides a user specified flag specifying whether linear interpolation is used for material properties between layers. By default, linear interpolation is used.

# Northridge Region 1D Velocity Model Configuration
#
# This 1D model was defined by Graves and Pitrarka 
# in Table 3 of their paper: doi: 10.1785/0120100057
# It is used in the SCEC Broadband Platform format
# for Los Angeles area simulations.
#

# Name of model.
version=Northridge Region 1D Velocity Profile

# Number of layers.
num_z=18

# Interpolation method. 
# Set interpolation=linear to turn on interpolation
# Set interpolation=none to turn off interpolation
interpolation=linear

# Columns
# Thickness (km) Vp (km/s) Vs(km/s) Density (gm/cm3) Qp  Qs
# Start of model.
#
--MODEL--

0.0020		1.7000	0.4500	2.0000	45.0000		22.5000
0.0040		1.8000	0.6500	2.1000	65.0000		32.5000
0.0060		1.8000	0.8500	2.1000	85.0000		42.5000
0.0080		1.9000	0.9500	2.1000	95.0000		47.5000
0.0100		2.0000	1.1500	2.2000	115.0000	57.5000
0.0700		2.4000	1.2000	2.2000	120.0000	60.0000
0.2000		2.8000	1.4000	2.3000	140.0000	70.0000
0.2000		3.1000	1.6000	2.4000	160.0000	80.0000
0.2000		3.4000	1.8000	2.4500	180.0000	90.0000
0.3000		3.7000	2.1000	2.5000	210.0000	105.0000
2.0000		4.4000	2.4000	2.6000	240.0000	120.0000
2.0000		5.1000	2.8000	2.7000	280.0000	140.0000
1.0000		5.6000	3.1500	2.7500	315.0000	157.5000
5.0000		6.1500	3.6000	2.8250	360.0000	180.0000
5.0000		6.3200	3.6500	2.8500	365.0000	182.5000
5.0000		6.5500	3.7000	2.9000	370.0000	185.0000
10.0000		6.8000	3.8000	2.9500	380.0000	190.0000
999.0000	7.8000	4.5000	3.2000	450.0000	225.0000

The following SCEC website provides more information about this model. https://scec.usc.edu/scecpedia/BBP_1D_LA_Basin_Model BBP1D LA Basin 1D Model

CVM-H v15.1

This is the most recent version of a southern California velocity model developed by the Harvard structural geology group.

More information about the CVM-H velocity model is available on a SCEC Website: SCEC Community Velocity Model - Harvard Website

CVM-S4

This is the best available version of the rule-based SCEC southern California velocity model. SCEC produced several iteration of this model from about 1995-2004. The later version are considered improvements on previous versions of the SCEC CVM models, so this replaces earlier version. The version available through UCVMC contains all available code fixes that have been added to the model since its release in 2004.

This models provides two regions that define a geotechnical layer (GTL), the return low Vs values, in the top 350m. These are polygon regions, as shown in the coverage maps, that provide GTL information Los Angeles region and in the Salton Sea area.

More information about the SCEC CVM-S4 is available on a SCEC Website at: SCEC CVM-S4 Website

CVM-S4.26

This is a tomography improved model of the CVM-S4 model. The tomography was performed on a 500m x 500m x 500m resolution mesh for the full region. The results are delivered on this fairly low resolution mesh, with linear interpolation used to determine material properties between mesh points. The tomography used a minimum Vs value for the region at about 900m/s, so this model does not deliver any low (or realistic) Vs values, when the GTL flag is set gtl = off. When the flag is set gtl = on, UCVM will add the Ely-Jordan Vs30-based GTL into the top 350 meters which provide velocities down to 200m/s in some areas.

# UTM Zone
utm_zone = 11

# Model directory
model_dir = s5

# GTL on or off?
gtl = off

# Number of cells in x, y, and z.
nx = 1536
ny = 992
nz = 100

# Depth, in meters
depth = 50000
depth_interval = 500

# Density scaling parameters
p5 = -0.0024189659303912917
p4 = 0.015600987888334450
p3 = 0.051962399479341816
p2 = -0.51231936640441489
p1 = 1.2550758337054457
p0 = 1.2948318548300342

# Corners, in UTM projection.
bottom_right_corner_e   = 596013.92402056302
bottom_right_corner_n   = 3368878.9393477398     
bottom_left_corner_e    = 10616.346941343043
bottom_left_corner_n    = 3863137.9139448642
top_right_corner_e      = 915108.80599173578
top_right_corner_n              = 3746813.1405760832
top_left_corner_e               = 329711.22891251586
top_left_corner_n               = 4241072.1151732076

CVM-S4.26.M01

This is a version of the CVM-S4.26 model that combines the tomography improved CVM-S4.26 model with some elements of the CVM-S rule-based geotechnical layer in the top 350m. This provides more realistic low Vs values often wanted in 3D ground motion simulations in the Los Angeles Region. The algorithm used to combine the tomography mesh, and the geotechnical layer are defined the UCVM site.

Cencal v08.3.0

Cencal is The USGS 3-D Geologic and Seismic Velocity Models of the San Francisco Bay region. This model provide a three-dimensional view of the geologic structure and physical properties of the region down to a depth of 45 km (28 miles). Construction of this 3D Bay Area model was a joint effort of the USGS Earthquake Hazards Program and the USGS National Cooperative Geologic Mapping Program.

Computational research has shown that the 3-D structure of the earth has a significant impact on how strongly an earthquake is felt at different locations and on the duration of the shaking. Because seismic waves propagate through different rock types with differing speeds that depend on the rock properties, the waves can be reflected and refracted as they travel through various rock types. These effects need to be understood in order to predict the shaking in future large earthquakes.

The Cencal 3-D models combine 100 years of surface geologic mapping by the USGS, the California Geological Survey, and many other institutions together with decades of research into the seismic properties of the rocks in the Bay Area. Traditional two-dimensional geologic maps show only the distribution of rock units at Earth's surface.

The Cencal Seismic Velocity Model is defined in two files, formatted as etrees.

  • Detailed model USGSBayAreaVM-08.3.0.etree.gz (1.6 GB) This is an Etree database file for inner, fine resolution model covering the San Francisco Bay area

  • Regional model USGSBayAreaVMExt-08.3.0.etree.gz(1.1 GB) This is an Etree database file for outer, coarser resolution model. The model fits around the detailed model and extends the region covered by the model. If you are only interested in the volume covered by the detailed model, you do not need to download this model.

  • Cencal Coverage Region

	Detailed	Regional (Extended)
Approx. Dimensions	290km	140km	650km	330km
SE corner (lon,lat)	-120.644051	37.050062	-118.944514	36.702176
SW corner (lon,lat)	-121.922036	36.320331	-121.930857	35.009018
NW corner (lon,lat)	-123.858493	38.424179	-126.353173	39.680558
NE corner (lon,lat)	-122.562365	39.174505	-123.273199	41.484869
  • Topography Support

  • Native Model Resolution

  Detailed model
  Elevation1	Horiz. Resolution	Vertical Resolution
  z > -400m	100m	25m
  -400m > z > -3200m	200m	50m
  -3200m > z > -6400m	400m	100m
  -6400m > z > -45000m	800m	200m

Transition from detailed model to extended model. This is a region 3.2km in width surrounding the detailed model. It is part of the extended model.

  Elevation	Horiz. Resolution	Vertical Resolution (see elevation note)
  z > -3200m	200m	50m
  -3200m > z > -6400m	400m	100m
  -6400m > z > -45000m	800m	200m

  Extended model
  Elevation	Horiz. Resolution	Vertical Resolution (see elevation model)
  z > -6400m	400m	100m
  -6400m > z > -45000m	800m	200m

  Elevation is given with respect to mean sea level, so -400m corresponds to 400m below mean sea level.
  • Native Projection: The detailed and regional velocity models are rectangular volumes in a Transverse Mercator (TM) projection with the following parameters:
Scale factor for central meridian: 0.99960000
Longitude of central meridian: -123.00000
Latitude of origin: 35.00000
False easting: 0.00000
False northing: 0.00000
Azimuths of sides: 53.638, 323.638

CCA 06

This is a trilinearly interpolated version of the 6th iteration of Po Chen and En-Jui Lee's full 3D tomographic inversions of the central California region. The inversions were done on a 500m coarse mesh, however the trilinearly interpolation allows this model to be queried at arbitrary precision. The GTL flag is default to off. When the flag is set gtl = on, UCVM will add the Ely-Jordan Vs30-based GTL into the top 500??350 meters.

# UTM Zone
utm_zone = 10

# Model directory
model_dir = i06

# GTL on or off?
gtl = off

# Number of cells in x, y, and z.
nx = 1024
ny = 896
nz = 100

# Depth, in meters
depth = 50000
depth_interval = 500

# Density scaling parameters
p5 = -0.0024189659303912917
p4 = 0.015600987888334450
p3 = 0.051962399479341816
p2 = -0.51231936640441489
p1 = 1.2550758337054457
p0 = 1.2948318548300342


# Corners, in UTM projection.
top_left_corner_e       = 503240.523120
top_left_corner_n       = 4051863.829470
bottom_left_corner_e    = 779032.901477
bottom_left_corner_n    = 3699450.983449
top_right_corner_e      = 906054.312483
top_right_corner_n      = 4367099.140150
bottom_right_corner_e   = 1181846.690839
bottom_right_corner_n   = 4014686.294129

# Data Layout Parameters 
seek_axis = fast-X
seek_direction = bottom-up

CS17.3

CyperShake Study 17.3 Central California Velocity Model. This is a 175m resolution mesh tiled from CCA06, CenCal, CVM-S4.26-M01 with 10km smoothing on each horizontal interface used in the CyberShake Study 17.3, a Central California Seismic Hazard Model. The GTL flag is default to off. When the flag is set, gtl = on, UCVM will add the Ely-Jordan Vs30-based GTL into the top 175 meters.

# UTM Zone
utm_zone = 11

# Model directory
model_dir = cs173

# GTL on or off?
gtl = off

# Number of cells in x, y, and z.
nx = 3200 
ny = 6960 
nz = 288 

# Depth, in meters
depth = 50400
depth_interval = 175

bottom_left_corner_e = 548969.079292
bottom_left_corner_n = 3459243.769232
top_left_corner_e    = -448610.671359
top_left_corner_n    = 4157755.975881
bottom_right_corner_e = 870071.761707
bottom_right_corner_n = 3917825.705794
top_right_corner_e   = -127508.133290
top_right_corner_n   = 4616338.305196

# Seek method, fast-X or fast-Y
seek_axis = fast-Y
seek_direction = top-down

CS17.3-H

CyperShake Study 17.3 Central California Velocity Model integrated with Harvard group's Santa Maria and San Joaquin Basin Models. The GTL flag is default to off. When the flag is set, gtl = on, UCVM will add the Ely-Jordan Vs30-based GTL into the top 175 meters.

# UTM Zone
utm_zone = 11

# Model directory
model_dir = cs173h

# GTL on or off?
gtl = off

# Number of cells in x, y, and z.
nx = 3200 
ny = 6960 
nz = 288 

# Depth, in meters
depth = 50400
depth_interval = 175

bottom_left_corner_e = 548969.079292
bottom_left_corner_n = 3459243.769232
top_left_corner_e    = -448610.671359
top_left_corner_n    = 4157755.975881
bottom_right_corner_e = 870071.761707
bottom_right_corner_n = 3917825.705794
top_right_corner_e   = -127508.133290
top_right_corner_n   = 4616338.305196

# Seek method, fast-X or fast-Y
seek_axis = fast-Y
seek_direction = top-down

State-wide Topography and Vs30 Model

To provide query by depth and query by elevation and Vs30 values for all models, UCVMC provides a statewide topography and Vs30 model. This is constructed as an etree data structure that stores the topography and vs30 values. The topography data is provided by USGS DEM. The Vs30 data is provide by converting Wills-Wald california site classifications to Vs30 values where ever the Wills-Wald map is defined. For regions outside of California, the Vs30 values were derived from the Wald vs30 topography relationship. The regional specification for the UCVMC topography and Vs30 etree are:

# UCVM model config file
# Projection parameters for reference
proj_str=+proj=aeqd +lat_0=36.0 +lon_0=-120.0 +x_0=0.0 +y_0=0.0
proj_origin=-129.75,40.75
proj_rot=55.0
proj_size=1800000.0,900000.0
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