Fast phase cross-correlation
Software to compute interstation correlations, including fast implementations of geometrically-normalized (CCGN), 1-bit correlation (1-bit CCGN), and phase cross-correlations (PCC) with and without using the GPU (Ventosa et al., SRL 2019).
The software packages of fast phase cross-correlation and ts-PWS stacking are basic building blocks in the design of efficient signal extraction methods from interstation correlations.
Main features
Computes 3 types of correlations:
- The standard (geometrically) normalized cross-correlations (GNCC).
- The 1-bit amplitude normalization followed by the GNCC (1-bit GNCC).
- The phase cross-correlation (PCC).
The computations of PCC are accerated in several ways:
- PCC is parallelized in the CPU using OpenMP 3.1 and in the GPU using CUDA (two independent codes).
- The computational cost of PCC with power of 2 is reduced to about twice the one of 1-bit GNCC.
Compilation
To compile execute "make" in the src directory. Use "make clean" to remove any previouly compiled code.
- The Seismic Analysis Code (SAC) is used to read and write sac files.
- The FFTW double and single precision libraries are used. If you have to compile them for your system, follow the fftw.org instructions.
- The SACHOME enviorment variable should provide the path to the directory where sac is
installed. For example, this can be defined in bash as:
export SACHOME=/opt/sac
Change "/opt/sac" to your current sac directory if necessary. - OpenMP 3.1 is used to speed up computations. When OpenMP is not available, use: make -f makefile_NoOpenMP".
Compile SAC
The precompiled sac libraries may not work in some systems/compilers. If you use the gcc compiler on Ubuntu 16.04 or 18.04 you may have errors similar to:
/usr/bin/ld: /opt/sac/lib/sacio.a(getfhv.o): relocation R_X86_64_32 against undefined symbol 'kmlhf' can not be used when making a PIE object; recompile with -fPIC
This can be solved by compiling the source version of SAC. From the source directory of sac do:
./configure --enable-optim=2 --prefix=/opt/sac CFLAGS='-march=native -fPIC'
make
make install
The key detail here is the -fPIC flag, you can adapt the other options to your needs. The flag --prefix=/opt/sac sets the directory where sac will be installed when doing "make install". You can change this directory, e.g., to keep using your current version of SAC for other purposes.
Warming up
- Read ./examples/example.sh
- Execute it, e.g., bash example.sh
- Do PCC_fullpair_1b for the parameters usage.
Origin of Phase Cross-Correlation
Schimmel, M., 1999. Phase cross-correlations: Design, comparisons, and applications, Bulletin of the Seismological Society of America, 89(5), 1366-1378.
Schimmel, M. and Stutzmann, E. & J. Gallart, 2011. Using instantaneous phase coherence for signal extraction from ambient noise data at a local to a global scale, Geophysical Journal International, 184(1), 494-506, doi:10.1111/j.1365-246X.2010.04861.x
Paper to be cited
Ventosa S., Schimmel M. & E. Stutzmann, 2019. Towards the processing of large data volumes with phase cross-correlation, Seismological Research Letters, 90(4), 1663-1669, doi:10.1785/0220190022
2020/10/01 Sergi Ventosa Rahuet (sergiventosa(at)hotmail.com)