Nick Rawlinson and Brian Kennett
Adaptive stacking provides a powerful and rapid procedure for estimating
traveltime residual patterns across a network of seismic stations.
The approach exploits predictions from some propagation model to
achieve an approximate alignment
of traces which are then stacked to form a reference trace. Iterative
improvement of the alignment by comparison of the reference trace with each
station trace leads to a direct estimate of the residuals from the
propagation model. Our implementation is fast and robust in the presence of
significant noise and waveforms of different character. The major difference
from earlier forms is the use of a direct minimization scheme for determining
the best match between the reference stacked trace and each recorded trace
based on an L3 measure of misfit. This approach has the benefit of generating
automatic error estimates. For teleseismic applications, the ak135 model has
proved to be very effective for selection of the window around the desired
phase and in achieving initial alignment. The approach can be applied to both
first motion (P) and later phases (e.g. PcP), with extraction of absolute
time via the improved signal to noise properties of the stacked trace, after
full alignment.
The purpose of this web page is to archive and distribute the adaptive
stacking code described in the paper:
Rawlinson, N. and Kennett, B. L. N. 2004. Rapid estimation of relative and
absolute delay times across a network by adaptive stacking.
Geophys. J. Int. , 157 , 332-340.
Download as PDF (1.5Mb)
This paper gives a detailed description of adaptive stacking, its history,
and potential applications. References are also made to papers which
describe other residual estimation techniques, such as Multi-Channel Cross
Correlation (MCCC) and optimum trace construction with simulated annealing.
Several examples which demonstrate adaptive stacking with real array data are
also provided.
1. Adaptive Stacking Code
The adaptive stacking code is written in FORTRAN 77, and should run on most
computers that have access to a fortran compiler such as g77. To obtain the
complete source code, a detailed manual and example input files, download the
Unix gzipped and tarred file below:
tcasv1.0.tar.gz (894 Kb)
To unpack the contents of this file, type something like:
gunzip -c tcasv1.0.tar.gz | tar xvof -
at the command prompt. The contents of the tar archive will be placed in a
subdirectory called astack .
2. ak135 Moveout Corrections
In order to use the adaptive stacking code, the input data (in the form of
trace time series) will need to be approximately aligned using model
predictions. In the case of teleseismic data, ak135 moveout
corrections should be sufficient. These can be obtained using the
ttimes traveltime software that is available for free at:
http://rses.anu.edu.au/seismology/soft/ttsoft.html
Alternatively, a simpler version of ttimes that only permits list
input and output for a specified phase can be downloaded below, and should be
easy enough to incorporate in your data extraction program.
aktimev1.0.tar.gz (51 Kb)
To unpack the contents of this file, type something like:
gunzip -c aktimev1.0.tar.gz | tar xvof -
at the command prompt. The contents of the tar archive will be placed in a
subdirectory called aktime . A README.txt file
explains how to compile and run the program.
For more information about adaptive stacking, please email