About BBP Services
Physics-based ground motion simulation, offered as an API — with the evidence that it works published alongside it.
What is BBP Services?
BBP Services runs the SCEC Broadband Platform as a hosted, metered REST API. You configure a rupture and a set of stations; the platform simulates the ground motion those stations would record, and returns seismograms, response spectra and the rupture description it generated.
Running the platform yourself means compiling a Fortran scientific code, downloading tens of gigabytes of Green's functions per region, and finding hardware to run it on. We do that once, so a simulation is an API call.
Site conditions come from the SCEC Unified Community Velocity Model, served through the same API so a station's Vs30 and its simulation come from one place.
Why the evidence is on the site
A simulation that looks convincing is not necessarily accurate. Every claim this service makes about its own accuracy is published rather than asserted: results against SCEC's curated validation earthquakes, and comparisons of simulated against recorded ground motion for real events, with the goodness-of-fit numbers and the caveats that qualify them.
Bias is published period by period rather than as a single average, because a simulation can pass on the mean while being well off at the period a particular structure cares about. See Verification & Validation.
Independence and attribution
This is an independent service. The Broadband Platform and the velocity models are the work of the Southern California Earthquake Center and its contributors; we host and operate them, and we are not affiliated with SCEC, USGS, or any other organisation whose data or software this service uses. Recorded seismograms used in verification come from public data centres.
What this service is not
Simulation output is a research and engineering product, not official hazard information. It describes what a modelled rupture would produce under a modelled crust — not what did happen, and not what will.
This service is not an emergency management or government agency, issues no alerts, and must not be used for emergency response or life-safety decisions. For authoritative earthquake information see the U.S. Geological Survey, and follow guidance from your local emergency management authorities.
Simulations are only as good as their inputs and the method's calibration. Each result is returned with the velocity model, method and source parameters that produced it, so it can be judged rather than taken on trust.
Supporting the service
Simulations run on cloud compute that costs real money, and results occupy real storage. Both are metered per account, and what a job cost is visible to the account that ran it.
Organisations relying on this service operationally are welcome to get in touch about support arrangements. Recent changes are listed on the updates page, and our privacy policy describes what we collect and how long we keep it.