- Ground-motion model is:
where PGA is in cm∕s2, aPGA = 0.4346, bPGA = -0.002459, SPGA,1 = 0.9259, SPGA,2 = 0.9338,
SPGA,3 = 0.9929, SPGA,4 = 0.9656, SPGA,5 = 0.9336 and σ = 0.2966.
- Use five site categories (from Eurocode 8):
- V s,30 > 800m∕s. Use SPGA,1. 43 stations, 396 records.
- 360 < V s,30 < 800m∕s. Use SPGA,2. 399 stations, 4190 records.
- 180 < V s,30 < 360m∕s. Use SPGA,3. 383 stations, 4108 records.
- V s,30 < 180m∕s. Use SPGA,4. 65 stations, 644 records.
- Site D or C underlain in first 20m with a stiffer layer of V s > 800m∕s. Use SPGA,5. 6 stations, 52
Use statistical method of Boore (2004) with parameters derived from KiK-Net profiles in order to extend
V s profiles down to 30m depth.
- Records from K-Net network whose digital stations have detailed geotechnical characterisation down to
- Retain only records from events whose focal depths < 25km.
- Convert MJMA to Mw using empirical conversion formula to be consist with other studies.
- Apply magnitude-distance cut-off to exclude distant records.
- Bandpass filter all records with cut-offs 0.25 and 25Hz. Visually inspect records for glitches and to retain
only main event if multiple events recorded.
- Find that one-stage maximum likelihood regression gives almost the same results.
- Also derive equations for other strong-motion parameters.