Animations and figures of seismicity automatically generated following large global earthquakes (Mag > 7).
Following all global earthquakes with magnitudes greater than 7, aftershock sequence animations and figures are automatically generated and made available in SPUD. The movies and figures are updated hourly for 10 days. Starting on August 1, 2020, events from the FDSN (USGS) and the GCMT catalogs are used in this product. Depending on type of plot or movie, marker colors refer to the event depth, number of days since the mainshock or total number of earthquakes. When available, GCMT magnitudes and reference origins are the preferred source. GCMT focal mechanisms are included in plots when they become available. Results are backfilled to 1980 using the GCMT catalog as reference.
The Aftershocks data product was initially released in December 2014 and was upgraded (R2) in August 2020 to enhance the plots and introduce additional animations and plots.
For each event, there will be:
- an aftershock sequence animation
- an aftershock sequence heatmap animation (when available)
- a seismicity map spanning 3 days before to 10 days after the mainshock
- a plot showing the distribution of aftershock magnitudes as time progresses
- two plots showing distribution of aftershocks along each of the strikes given by the GCMT solution (when available)
- two plots showing distribution of aftershocks with depth along each of the strikes given by the GCMT solution, when available (when available)
For the figures generated, the radius of aftershocks plotted decreases as mainshock magnitude decreases:
Mag ≥ 9.0 1000 km
9.0 > Mag ≥ 8.5 500 km
8.5 > Mag ≥ 8.0 400 km
8.0 > Mag ≥ 7.0 300 km
7.0 > Mag ≥ 6.0 200 km
Mag < 6.0 100 km
Example animations and figures:
(left) event animation and (right) event heatmap animation: from a day before the mainshock to 10 days after the mainshock with colors fading over the course of one day. Click on an image to play the corresponding animation.
Citations and DOIs
To cite the IRIS DMC Data Products effort:
- Hutko, A. R., M. Bahavar, C. Trabant, R. T. Weekly, M. Van Fossen, T. Ahern (2017), Data Products at the IRIS‐DMC: Growth and Usage, Seismological Research Letters, 88, no. 3, https://doi.org/10.1785/0220160190.
To cite the IRIS DMC Aftershocks data product or reference use of its repository:
- IRIS DMC (2014), Data Services Products: Aftershocks, https://doi.org/10.17611/DP/AS.1.
To cite a particular Aftershocks data product via its DOI:
– select the event of interest
– click on Citations to obtain its DOI
United States Geological Survey (USGS)
Global CMT (GCMT) catalog:
- Dziewonski, A. M., T.-A. Chou and J. H. Woodhouse, Determination of earthquake source parameters from waveform data for studies of global and regional seismicity, J. Geophys. Res., 86, 2825-2852, 1981. https://doi.org/10.1029/JB086iB04p02825
- Ekström, G., M. Nettles, and A. M. Dziewonski, The global CMT project 2004-2010: Centroid-moment tensors for 13,017 earthquakes, Phys. Earth Planet. Inter., 200-201, 1-9, 2012. https://doi.org/10.1016/j.pepi.2012.04.002
- Alexander Hutko
- R1 Aftershocks online
- R2 Aftershocks online