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Event Id:
C202107251017A
MW:
5.8
Latitude, Longitude:
(-29.8900, -176.3500)
Depth: 12.0 km
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Focal Mechanism
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Scripts
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3D synthetic seismograms accurate to periods >=17s for model S362ANI (Kustowski2008) and crustal model CRUST2.0 (Bassin2000) calculated based upon the spectral-element method. Duration: 100mins (MW<7.5), 200mins (MW>=7.5). Computed using Specfem3D_Globe 7.0.0.
1D synthetic seismograms accurate to periods of 8s and longer for model PREM (Dziewoński/Anderson1981) calculated based upon normal-mode summation. Duration: 100mins (MW<7.5), 200mins (MW>=7.5).
CloseQuick CMT (Centroid Moment Tensor) Solution (globalcmt.org)
CMT 2021 7 25 10 17 9.30 -29.8900 -176.3500 12.0 5.8 5.8 C202107251017A event name: C202107251017A time shift: 0.0000 half duration: 2.0000 latitude: -29.8900 longitude: -176.3500 depth: 12.0000 Mrr: 5.190000e+24 Mtt: -3.630000e+23 Mpp: -4.830000e+24 Mrt: 1.630000e+24 Mrp: 4.450000e+24 Mtp: -1.440000e+24Close
This figure illustrates the format of the CMTSOLUTION file used to generate synthetic seismograms. Earthquake locations are given in geographic coordinates.
time shift:
time difference between the earthquake origin time
and the centroid time
half duration: source half duration.
It is set to zero during computation of synthetic seismograms,
which corresponds to simulating synthetics with a
step (Heaviside) source-time function,
i.e., the moment-rate function is a delta function in time.
M: moment tensor
Mw: moment magnitude reported in the CMT catalogue
M0, Mw: approximate estimations of
the scalar moment and the moment magnitude
STATIONS file
This figure illustrates the format of the STATIONS file used to generate synthetic seismograms. Station locations are given in geographic coordinates.
process_data.pl: process observed seismograms
This is an example of the usage of the process_data.pl script:
process_data.pl -m CMTSOLUTION -s 1.0 -l 0/4000 -i -f -t 40/400 -p -x proc DATA/1999.330{*}.LH?.SAC
-m CMTSOLUTION: set event information.
-s 1.0: resample the data to a sampling rate of 1 sps.
-l 0/4000: cut data between 0 and 4000 seconds.
-i -f: deconvolve the instrument response from the
observed data using the pole-zero files provided in the same directory
of the data and apply a band-pass filter.
-t 40/400: corner periods of the filter are 40 and 400 seconds.
-p: pick P and S arrivals according to iasp91 model.
-x proc: add *.proc extension to the filenames of the processed data.
DATA/*.LH?.SAC: input files.
NOTE: Please make sure that the SAC, saclst, and IASP91 packages are installed properly on your system, and that the environment variables (e.g., PATH) are set properly before running the script.
Closeprocess_syn.pl: process synthetic seismograms
This is an example of the usage of the process_syn.pl script:
process_syn.pl -S -m CMTSOLUTION -h -a STATIONS -s 1.0 -l 0/4000 -i -f -t 40/400 -p -x proc SEM/*.MX?.sem.sac
-S: synthetics are in SAC binary format.
-m CMTSOLUTION: set event origin, location and half duration.
-h: convolve synthetics with a triangle source-time function
with the half duration provided in the
CMTSOLUTION file.
-s 1.0: resample the synthetics to a sampling rate of 1 sps.
-l 0/4000: cut synthetics between 0 and 4000 seconds.
-f: use the same band-pass filter used in the deconvolution of the observed data.
-t 40/400: corner periods of the filter are 40 and 400 seconds.
-p: pick P and S arrivals according to iasp91 model.
-x proc: add *.proc extension to the filenames of the processed data.
SEM/*.MX?.sem.sac: input files.
NOTE: Please make sure that the SAC, saclst, and IASP91 packages are installed properly on your system, and that the environment variables (e.g., PATH) are set properly before running the script.
Closerotate.pl: rotate seismograms
rotate.pl rotates the horizontal components (e.g. LHN/LHE) of both observed and synthetic seismograms to the radial and the transverse directions (e.g. LHR/LHT).
This is an example of the usage of the rotate.pl script:
rotate.pl -l 0 -L 4000 -d DATA/{*}.LH?.SAC.proc rotate.pl -l 0 -L 4000 -d SEM/{*}.LH?.sem.sac.proc
-l 0: start time of the seismograms at 0 seconds.
-L 4000: end time of the seismograms at 4000 seconds.
-d: directory where the processed horizontal seismograms are located and the radial/transverse components will be written.
NOTE: Please make sure that the SAC and saclst packages are installed properly on your system, and that the PATH environment variable is set properly before running the script.
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