The Event Plots product is a suite of plots that are automatically generated following all
global M6.0+ earthquakes (M5.0+ for continental US). The plots use all open broadband data
available at the IRIS DMC at the time the product was generated.
Station maps:
Basic station map and additional equi-distant & azimuthal maps with colors representing
first P-arrival (P/Pdiff/PKP) signal to noise ratio.
Global body wave record sections:
Produced using various data sets (all IRIS DMC data/GSN) and are 'combed' to show the most
even distribution of stations that meet a minimum signal to noise ratio criteria.
Phase aligned record sections:
Produced using all available IRIS broadband data and are 'combed' to show the most even
distribution of stations that meet a minimum signal to noise ratio criteria. Records
aligned on P, plot velocity, while records aligned on S and SKS plot displacement.
USArray body & surface wave record sections:
Body wave record sections are combed and show BH data. The surface wave plots show combed
USArray LH data filtered between 20-125 sec and share the same amplitude scaling for all
three vertical, radial and transverse components. The enhanced record sections use the
same traces, but display the amplitudes using a nonlinear color scale, which can show a
wider dynamic range of amplitudes.
Virtual array P-waves & vespagrams:
First P arrivals aligned using multi-channel cross correlation and vespagrams are shown
for all data from a virtual regional network formed from all available stations within a
region. Virtual arrays are: TA=central US, mostly USArray data, UW=Pacific Northwest,
CA=California and SW US, AK=AK and AV networks in Alaska, AU=Australia, EU=central/western
Europe.
Global body wave stacks:
Generated by stacking of envelope functions in distance bins. The envelopes are mean
pre-Pwave noise removed, square-rooted and linearly stacked, and weighted nonlinearly by
the number of contributing seismograms in order to more evenly illuminate the entire wavefield.
P-wave coda stacks:
Envelopes of P-wave data from 30-95* are stacked in azimuthal and distance bins. For the largest
earthquakes, the azimuthal pattern can indicate rupture direction. Coda durations have been shown
to correlate with depth. For large earthquakes, the stack of all bins (red line) can often
provide a rough estimate of the rupture duration and character (e.g. single event vs doublet).
Travel time anomalies, smoothing of the envelopes, and sometimes depth phase interference will
broaden the stack such that even an impulsive M6.0 event may appear to have a ~10 sec
duration before the characteristic coda decay sets in.
This product is automatically generated without human review.
