Seismic waves across the region
Seismographs record the shaking at one spot. A wave simulation computes it everywhere at once, so you can watch the waves leave the fault and cross the map.
More earthquakes
New movies appear here automatically after qualifying earthquakes (M4.5 and up).
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VALIDATION EVENT
VALIDATION EVENT
VALIDATION EVENT
How the movies are made
We run SW4, a seismic wave simulation code, through the bbpservices.net API, the same service that provides our BBP simulations.
SW4 uses the same earthquake source and the same layered (1D) model of the crust as BBP. BBP returns a seismogram at each chosen station. SW4 computes the motion across the whole surface, and that wavefield is what the movies show.
SW4 and BBP agree at the same sites
For eight validation earthquakes, the median correlation between SW4 and BBP low-frequency seismograms at stations within 20 km ranged from 0.989 to 0.998, in the band from 0.1 to 0.5 Hz.
What these movies do not show
The model is a layered crust with a flat surface, so there is no basin amplification and no terrain. It holds waves below 0.5 Hz only. The colors are ground velocity at that low frequency. They are not broadband peak velocity and are not converted to intensity.