International Federation of Digital Seismograph Networks

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Instrument:  Synthetic seismograms generated by the Global ShakeMovie project (Princeton University)


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.


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.


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.


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


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