- Ground-motion model is:
where Y is in cm∕s2, C1 = 3.88, C2 = 1.12, C3 = -1.65, R0 = 15, C4 = 0.41 and σ = 0.71.
- Use two site categories (mean opinion of seven specialists who classified sites into three categories: soft alluvium,
crystalline rock and intermediate):
- Rock: 34+4 records. Japanese sites have diluvium with depth to bedrock H < 10m. Alaskan sites
have PGV∕PGA ≈ 66 ± 7cms-1g-1.
- Alluvium: 71+12 records. Japanese sites have diluvium H > 10m or alluvium H < 10m, and
alluvium with H < 25m as well as soft layers with thickness < 5m. Alaskan sites have PGV∕PGA >
66 ± 7cms-1g-1.
- 70% of records from ground level or basement of buildings with two storeys or less. Rest from buildings
with up to eight storeys.
- Some (16) Greek records manually digitized and baseline corrected, some (22) Greek records manually
digitized and filtered and rest of the Greek records automatically digitized and filtered.
- Due to lack of data for 7.0 < Ms < 7.5 include shallow subduction data from other regions with similar
seismotectonic environments (Japan and Alaska) using criteria i) depth < 35km, ii) Mw or MJMA between
7.0 and 7.5, iii) instruments triggered before S-wave, iv) free-field recording, v) surface geology known at
station. Note Ms, Mw and MJMA are equivalent between 6.0 and 8.0.
- Focal depths between 0km (13km) and 18km (31km).
- Most data from Ms < 5.5 and from R < 50km.
- Use four step regression procedure. First step use only Greek data from Ms > 6.0 (9 ≤ R ≤ 128km,
14 records) for which distances are more reliable (use both hypocentral and epicentral distance find
epicentral distance gives smaller standard deviation) to find geometrical coefficient C31 and R0 ignoring
soil conditions. Next find constant (C12), magnitude (C22) and soil (C42) coefficients using all data. Next
recalculate geometrical (C33) coefficient using only Greek data with Ms > 6.0. Finally find constant (C14),
magnitude (C24) and soil (C44) coefficients using all the data; final coefficients are C14, C24, C33 and C44.
- Plot residuals against Ms and R and find no apparent trends. Find residuals (binned into 0.2 intervals)
fit normal distribution.