- Ground-motion model is:
where PGA is in cm∕s2, for Iberian Peninsula lnC0 = -5.13, C1 = 2.12 and γ = 0.0039, for NE region
lnC0 = -4.74, C1 = 2.07 and γ = 0.0110 and for SSE region lnC0 = -5.30, C1 = 2.21 and γ = 0.0175
(σ is not given).
- Derive equations for two regions:
- South south-east part of the Iberian peninsula, from the Guadalquivir basin to the Mediterranean
Sea, including the Betic Cordillera, 140 records from 5 stations.
- North-east part of the Iberian peninsula, including the Pyrenees, the Catalan Coastal Ranges, the
Celtiberian chain and the Ebro basin, 107 records from 3 stations.
- Use vertical-component short-period analogue records of Lg-waves (which are believed to have the largest
amplitudes for the period range 0.1 to 1s) from regional earthquakes in Iberian Peninsula.
- Processing procedure is: digitise seismogram using irregular sampling rate to get better sampling at
peaks and ‘kinks’, select baseline, apply cubic spline interpolation and compare original and digitised
seismograms. Next the Fourier amplitude spectrum is computed and the instrument amplitude response
- Estimate PGA using the maximum value of pseudo-absolute acceleration obtained from Fourier amplitude
spectra. Derived equations are for characteristic frequency of 5Hz.
- Compare estimated PGAs with observed PGAs from five earthquakes and find good agreement.
- Use 5Hz γ values from Garcia-Fernandez and Canas (1992) and Vives and Canas (1992).