- Ground-motion model is:
where a is in cm∕s2, α0 = 1.237, α1 = 1.519, α2 = -0.0313, α3 = -0.844, α5 = -0.004 and σ = 0.780.
- Exclude records from soft soil sites or with previously known site effects (amplification or deamplification).
- Focal depths between 5 and 80km.
- Also derive equation using functional form lna = α0 + α1M + α2 lnR + α4R.
- Select records from stations located along the seismically active Mexican Pacific coast.
- Only use records from earthquakes with M > 4.5.
- Exclude data from normal faulting earthquakes using focal mechanisms, focal depths, location of epicentre
and characteristics of records because subduction zone events are the most dominant and frequent type of
- Use Mw because consider best representation of energy release.
- Visually inspect records to exclude poor quality records.
- Exclude records from dams and buildings.
- Exclude records from ‘slow’ earthquakes, which produce smaller short-period ground motions.
- Correct accelerations by finding quadratic baseline to minimize the final velocity then filter using most
appropriate bandpass filter (low cut-off frequencies between 0.05 and 0.4Hz and high cut-off frequency of
- Use data from 105 stations: 7 in Chiapas, 6 in Oaxaca, 6 in Colima, 19 in Jalisco, 49 in Guerrero, 14 in
Michoacán and 6 near the Michoacán-Guerrero border.