Data Services Newsletter

Volume 16 : No 3 : Winter 2014

Global stacks

Global stacks of up to a million event-windowed seismograms are made by stacking short-term to long-term average (STA/LTA) functions of the data in different frequency bands for vertical broadband data (1990-2012) available from the IRIS DMC. Long-period versions include vertical and horizontal component data. Plots are available for each component and frequency band analyzed. For users wishing to plot or analyze the stacks themselves, ascii files with the STA/LTA stack values as well as values from stacking envelope functions are also available.

Global stacks page:
http://ds.iris.edu/ds/products/globalstacks

CompositeStack
This composite figure shows the seismic wavefield imaged with global STA/LTA stacks from data available from IRIS from >2500 shallow earthquakes from 1995-2013 using different components (vertical, radial & transverse) in different frequency bands. This composite image combines global stacks from broadband vertical data filtered around 1, 2, 3, 4, 6 & 8 seconds periods (light blue) and long period data low-pass filtered below 10 s for vertical (dark blue), radial (green), and transverse (red) component data.

Poster size CMYK printer version of this plot

by Alex Hutko (IRIS Data Management Center)