SeismoLab
Load earthquake ground-motion records and see what is in them — time series, ground-motion parameters, response spectra, filtering and Fourier spectra. Everything is computed in your browser; the records never leave your computer.
What it computes
Records in, several at once
Drop in accelerograms: PEER NGA .AT2 records, two-column time–acceleration files, single-column files, or a text layout you describe. The format is detected and the parse settings filled in for you.
Time series
Acceleration, with velocity and displacement integrated from it, Arias intensity and specific energy density over time, and the raw data as a table.
Ground-motion parameters
Peak acceleration, velocity and displacement with their times, Vmax/Amax, RMS values, Arias intensity and specific energy density, side by side for every record loaded.
Response spectrum
Elastic spectra by Newmark time integration, over a period range and step you choose, for several damping ratios at once, with the values in a table you can copy.
Filtering
Butterworth low-pass, high-pass, band-pass and band-stop filters, with the filter’s frequency response shown beside the record.
Fourier spectra
Fourier amplitude or power spectra, raw or smoothed with the Konno-Ohmachi window.
SeismoLab analyses records, not structures: to run a response-spectrum analysis of a building, use Structural.