Test Cases CVM S4.26

CVM-S4.26

CVM-S4.26 is a southern California seismic velocity model. En Jui Lee and Po Chen developed CVM-S4.26 using full 3D tomographic techniques (F3DT). Lee and Chen based their starting CVM on the SCEC CVM version 4, which is the forth version of a SCEC rule-based southern California velocity model (Kohler et al., 2005). They used CVM-S4 as a starting model, on a 500 meter resolution for a ~400km x ~400km region of southern California. The tomography processing improved the earth structure model each iteration, using both well-observed minor earthquakes, and ambient noise techniques (Lee E., et al., 2014). Many ground motion validation simulations of historic earthquakes, using CVM-S4.26, show much better fit to observation than the same simulation using the starting model.

The inversion results are defined on a grid-based rectangular volume mesh-based representation of a large region of southern California from 0 depth down to about 50km. This model can be accessed through UCVM standard query interface, including the command line ./ucvm_query.py script. The UCVM query software will return material properties for locations between CVM-S4.26 grid points using tri-linear interpolation of values on grid points nearest the given location.

Test projection correction

Late 2016, a modification was made to the CVM-S4.26 projection algorithm. The current acceptance tests do not include a test to confirm this projection change is implemented correctly. However, the change can be confirmed by reviewing source code in current UCVMC release.

Test invalid pts

-112.0749  33.4494 300.
-118.5     33.875  0.0
-118.5000  33.8750 -500.000 
-118.5000  33.8750 0.000
-118.5000  33.8750 1000.000 
-118.5000  33.8750 4000.000 
-118.5000  33.8750 50000.000 
-118.5000  33.8750 60000.000

scecadms-MacBook-Pro-2:t1 maechlin$ ./bin/ucvm_query -f ./conf/ucvm.conf -m cvms5 < invalid_pts.txt
Using Geo Depth coordinates as default mode.
 -112.0749    33.4494    300.000    330.618    250.865       none      0.000      0.000      0.000       none      0.000      0.000      0.000       none      0.000      0.000      0.000
 -118.5000    33.8750      0.000    -59.946    180.000      cvms5   1287.871    825.000   2017.052       none      0.000      0.000      0.000      crust   1287.871    825.000   2017.052
 -118.5000    33.8750   -500.000    -59.946    180.000       none      0.000      0.000      0.000       none      0.000      0.000      0.000       none      0.000      0.000      0.000
 -118.5000    33.8750      0.000    -59.946    180.000      cvms5   1287.871    825.000   2017.052       none      0.000      0.000      0.000      crust   1287.871    825.000   2017.052
 -118.5000    33.8750   1000.000    -59.946    180.000      cvms5   4316.372   2541.568   2422.857       none      0.000      0.000      0.000      crust   4316.372   2541.568   2422.857
 -118.5000    33.8750   4000.000    -59.946    180.000      cvms5   5145.999   3020.703   2534.094       none      0.000      0.000      0.000      crust   5145.999   3020.703   2534.094
 -118.5000    33.8750  50000.000    -59.946    180.000       none      0.000      0.000      0.000       none      0.000      0.000      0.000       none      0.000      0.000      0.000
 -118.5000    33.8750  60000.000    -59.946    180.000       none      0.000      0.000      0.000       none      0.000      0.000      0.000       none      0.000      0.000      0.000

CVM-S4.26 model ends at the depth of 50Km

Plot a depth profile of a point inside CVM-S4.26 shows how deep the model extends.

./plot_depth_profile.py -d vp -b 0 -e 60000 -v 100 -c cvms5 -s 33.5,-118.05

For a point outside of the model,

./plot_depth_profile.py -d vp -b 0 -e 60000 -v 100 -c cvms5 -s 37,-121

Surface image of Los Angeles region with CVM-S4.26 model

Plot a horizontal slice to show the Vs values in Los Angeles region at 900m depth.

./plot_horizontal_slice.py -b 33.5,-118.5 -u 34.5,-117.5 -e 900 -d vs -c cvms5 -a s -s 0.001

Test no background model for cvm-s4.26

Pick a point outside the cvm-s4.26 area and show it return no data.

-121 37 is outside point
-121 36 is inside point

Using Geo Depth coordinates as default mode.
 -121.0000    37.0000      0.000    175.470    373.072       none      0.000      0.000      0.000       none      0.000      0.000      0.000       none      0.000      0.000      0.000
 -121.0000    36.0000      0.000    366.540    385.100      cvms5   5240.055   2908.186   2502.674       none      0.000      0.000      0.000      crust   5240.055   2908.186   2502.674

Enabling the GTL in CVM-S4.26

Adjusting the installdir/model/cvms5/data/config parameter for GTL to 'on' enables the GTL in CVM-S4.26

Plot Cross section with the command,

./plot_cross_section.py -b 34,-117.7 -u 34,-117.5 -h 100 -v 20 -d vs -c cvms5 -a d -s 0 -e 2000 -o cvm5

with GTL 'off' (default),

with GTL 'on',

UCVM can add an external GTL to the CVM-S4.26 model.

The CVM-S4.26 model can add the Ely-Jordan GTL as an external modification.

./bin/ucvm_query -f ./conf/ucvm.conf -m cvms5,elygtl:ely -z 0,350 < ./tests/inputs/test_latlons_socal_pts.txt > cvms5_elygtl_res.txt

• CVM-S4.26 with external GTL added