This document contains instructions for running application Response Spectra within the EPISODES Platform. The application computes the response spectra of acceleration data time series using the Duhamel integral technique. Adapted from code originally written by Loïc Viens.

To obtain more general information about working with applications within the Platform, see Applications Quick Start Guide.


CATEGORY Source and Shaking Parameters Estimation

KEYWORDS Response spectra

CITATION If you use the results or visualizations retrieved from this application in a publication, then you must cite the data source as follows:

Viens, Loïc and Marine A. Denolle (2019) Long‐Period Ground Motions from Past and Virtual Megathrust Earthquakes along the Nankai Trough, Japan. Bulletin of the Seismological Society of America, 109(4), 1312–1330

Orlecka-Sikora, B., Lasocki, S., Kocot, J. et al. (2020) An open data infrastructure for the study of anthropogenic hazards linked to georesource exploitation., Sci Data 7, 89, doi: 10.1038/s41597-020-0429-3.

This application uses acceleration miniseed files as input to calculate the response spectra. If the user's data is in velocity, it can be converted into acceleration using the MseedToMseed application. 

Inputs

  1. Acceleration in miniseed format
  2. Damping factor [0.00, 0.99]
    • Also known as a damping ratio.
    • Describes how vibrations decay over time. Generally response spectrum amplitudes will decrease when the damping ratio is increased.
    • Default is 0.05 for 5%, as most ground motion models are developed for a reference damping value of 5%.
    • Values ranging from 0.5% to 30% are not uncommon.
  3. Maximum acceleration period [s] (min. 0.00) 
    • The maximum value of the horizontal axis in the 'SA' and 'PSA' plots
    • Default is 4 seconds
  4. Maximum velocity period [s] (min. 0.00) 
    • The maximum value of the horizontal axis in the 'SV' and 'PSV' plots
    • Default is 4 seconds
  5. Maximum displacement period [s] (min. 0.00) 
    • The maximum value of the horizontal axis in the 'SD' plot
    • Default is 10 seconds


Outputs

Plots in png format and data values in csv format for:

'SA'  : Acceleration Spectra

'PSA' : Pseudo-acceleration Spectra

'SV'  : Velocity Spectra

'PSV' : Pseudo-velocity Spectra

'SD'  : Displacement Spectra


The plots are of spectral response vs period, where the maximum period shown can be configured using the input parameters. Typically for displacement, up to 10 seconds is shown and for acceleration and velocity, up to 4 seconds.

Pseudo-acceleration and pseudo-velocity spectra are approximations calculated directly from the displacement spectra.

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