TY - JOUR
T1 - Cartesian Meshing Spherical Earth (CMSE)
T2 - A Code Package to Incorporate the Spherical Earth in SPECFEM3D Cartesian Simulations
AU - Li, Guoliang
AU - Tao, Kai
AU - Chen, Min
AU - Li, Jiaqi
AU - Maguire, Ross
AU - Ma, Xiaodan
N1 - Funding Information:
The authors thank the Institute for Cyber-Enabled Research (ICER) at Michigan State University, the Extreme Science and Engineering Discovery Environment (XSEDE supported by NSF Grant ACI-1053575) for providing the high-performance computing resources.
Funding Information:
The authors also sincerely thank Editor Allison Bent and the reviewer Tianchi Liu for their constructive comments and suggestions, which significantly improved the quality of this article. This research is supported by NSF Grant 1942431 and startup funds of M. C. at Michigan State University. In addition, coauthor R. M. was supported by NSF-EAR postdoctoral followship 1806412.
Publisher Copyright:
© Seismological Society of America.
PY - 2022/3/1
Y1 - 2022/3/1
N2 - The SPECFEM3D_Cartesian code package is widely used in simulating seismic wave propagation on local and regional scales due to its computational efficiency compared with the one-chunk version of the SPECFEM3D_Globe code. In SPECFEM3D_Cartesian, the built-in meshing tool maps a spherically curved cube to a rectangular cube using the Universal Transverse Mercator projection (UTM). Meanwhile, the geodetic east, north, and up directions are assigned as the local x-y-z directions. This causes coordinate orientation issues in simulating waveform propagation in regions larger than 6° × 6° or near the Earth's polar regions. In this study, we introduce a new code package, named Cartesian Meshing Spherical Earth (CMSE), that can accurately mesh the 3D geometry of the Earth's surface under the Cartesian coordinate frame, while retaining the geodetic directions. To benchmark our new package, we calculate the residual amplitude of the CMSE synthetics with respect to the reference synthetics calculated by SPECFEM3D_Globe. In the regional scale simulations with an area of 1300 km × 1300 km, we find a maximum of 5% amplitude residual for the SPECFEM3D_Cartesian synthetics using the mesh generated by the CMSE, much smaller than the maximum amplitude residual of 100% for the synthetics based on its built-in meshing tool. Therefore, our new meshing tool CMSE overcomes the limitations of the internal mesher used by SPECFEM3D_Cartesian and can be used for more accurate waveform simulations in larger regions beyond one UTM zone. Furthermore, CMSE can deal with regions at the south and north poles that cannot be handled by the UTM projection. Although other external code packages can be used to mesh the curvature of the Earth, the advantage of the CMSE code is that it is open-source, easy to use, and fully integrated with SPECFEM3D_Cartesian.
AB - The SPECFEM3D_Cartesian code package is widely used in simulating seismic wave propagation on local and regional scales due to its computational efficiency compared with the one-chunk version of the SPECFEM3D_Globe code. In SPECFEM3D_Cartesian, the built-in meshing tool maps a spherically curved cube to a rectangular cube using the Universal Transverse Mercator projection (UTM). Meanwhile, the geodetic east, north, and up directions are assigned as the local x-y-z directions. This causes coordinate orientation issues in simulating waveform propagation in regions larger than 6° × 6° or near the Earth's polar regions. In this study, we introduce a new code package, named Cartesian Meshing Spherical Earth (CMSE), that can accurately mesh the 3D geometry of the Earth's surface under the Cartesian coordinate frame, while retaining the geodetic directions. To benchmark our new package, we calculate the residual amplitude of the CMSE synthetics with respect to the reference synthetics calculated by SPECFEM3D_Globe. In the regional scale simulations with an area of 1300 km × 1300 km, we find a maximum of 5% amplitude residual for the SPECFEM3D_Cartesian synthetics using the mesh generated by the CMSE, much smaller than the maximum amplitude residual of 100% for the synthetics based on its built-in meshing tool. Therefore, our new meshing tool CMSE overcomes the limitations of the internal mesher used by SPECFEM3D_Cartesian and can be used for more accurate waveform simulations in larger regions beyond one UTM zone. Furthermore, CMSE can deal with regions at the south and north poles that cannot be handled by the UTM projection. Although other external code packages can be used to mesh the curvature of the Earth, the advantage of the CMSE code is that it is open-source, easy to use, and fully integrated with SPECFEM3D_Cartesian.
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U2 - 10.1785/0220210131
DO - 10.1785/0220210131
M3 - Article
AN - SCOPUS:85126759670
SN - 0895-0695
VL - 93
SP - 986
EP - 996
JO - Seismological Research Letters
JF - Seismological Research Letters
IS - 2
ER -