- Ground-motion model is: where ah is in g, C1 = -3.4360, C2 = 0.8532, C3 = -0.0192, C4 = -0.9011, C5 = -0.0020, C6 = -0.0316,
h0 = 4.24 and σ = 0.424.
- Use two site categories:
S = 0
S = 1
- Use one-stage method because of the predominance of earthquakes with single recordings in the set.
- Note that it is very important to choose a functional form based as much as possible on physical grounds
because the data is sparse or non-existent for important ranges of distance and magnitude.
- Carefully verify all the distances in set.
- Use focal depths from (in order of preference): special reports (such as aftershock monitoring), local agencies
and ISC and NEIS determinations. Focal depths < 30km.
- Do not use ML or mb because of a variety of reasons. One of which is the saturation of ML and mb at
higher magnitudes (ML,mb > 6).
- If more than one estimate of Mw made then use average of different estimates.
- Use PGAs from: a) digital or digitised analogue records which have been baseline corrected and filtered,
b) data listings of various agencies and c) other literature. Difference between PGA from different sources
is found to be small.
- Also derive equations assuming C3 = 0 (using rock and soil records and only soil records) and C3 = 0,
C4 = -1 and C6 = 0 (using only rock records).
- Include records from Nahanni region and find similar results.
- Also derive equations for Australia (115 records from 86 earthquakes, 2.4 ≤ Mw ≤ 6.1, 1 ≤ de ≤ 188km)
and N. E. China (Tangshan) (193 records from 64 earthquakes, 3.5 ≤ Mw ≤ 7.5, 2 ≤ de ≤ 199km) . Find
considerable difference in estimated PGAs using the equations for the three different regions.