Instrument: Synthetic seismograms
generated by the Global ShakeMovie project (Princeton University)
Description:
The Global ShakeMovie project
calculates synthetic seismograms for all quick CMTs
reported by the Global CMT Project
in near real time.
These synthetics are the results of simulations carried
out on a large computer cluster. 1D synthetic seismograms
are calculated for PREM (Dziewonski & Anderson, 1981) based upon normal
mode summation. 3D synthetic seismograms are calculated for S362ANI (Kustowski et al., 2008)
and Crust2.0 (Bassin et al., 2000) based on the spectral-element method using the software
package SPECFEM3D_GLOBE.
The synthetics are generated using the source parameters determined
by the Global CMT Project.
Usage:
The record length of the synthetics is 100 minutes for events
with magnitudes less than 7.5 and 200 minutes for events with magnitudes
greater than or equal to 7.5. The 1D mode simulations are accurate at periods of 8 seconds
and longer, whereas the spectral-element simulations are
accurate between periods from 17 to 500 seconds. The synthetics do
not include a source-time function, users
should convolve the synthetics with a source-time
function of their choosing before comparing them to actual
recorded data. Scripts useful for preparing and processing these
synthetics are available from the
Global ShakeMovie site, including SAC-based scripts to convolve
synthetics with a half duration.
Availability:
The synthetics are available both from the Global
ShakeMovie site and the IRIS
Data Management Center. The synthetics
available from the IRIS DMC are in the SEED format with
newtork code SY and share
the station code from the sites which they were calculated for.
In order to further distinguish these synthetics from other synthetics
and data recorded at the site, SEED location IDs are used
(S1 and S3) in addition to an X instrument in the channel
codes.
Overview:
Simulation |
SEED Location ID |
SEED Channel Codes |
Frequency Band |
Sampling rate |
1D normal modes |
S1 |
LXE, LXN, LXZ |
8 seconds and longer |
0.5 Hz |
3D spectral-element |
S3 |
MXE, MXN, MXZ |
17-500 seconds |
~6.192 Hz |
References:
Tromp.
J., Komatitsch, D., Hjörleifsóttir, V., Liu, Q., Zhu,
H., Peter, D., Bozdag, E., McRitchie, D., Friberg, P., Trabant, C.,
Hutko, A., 2010. Near
real-time simulations of global CMT earthquakes, Geophys.
J. Int., 183, 381-389
PREM: Dziewonski & Anderson, 1981
S362ANI: Kustowski et al., 2008
Crust2.0: Bassin et al., 2000
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