- Ground-motion model is: where Y is in g, b1 = -0.682, b2 = 0.253, b3 = 0.036, b5 = -0.562, bV = -0.297, V A = 1381, h = 4.48
and σ = 0.562.
- Use three site categories:
- Average shear-wave velocity, V S, is 200m∕s. 40 records.
- Average shear-wave velocity, V S, is 400m∕s. 24 records.
- Average shear-wave velocity, V S, is 700m∕s. 29 records.
Actual shear-wave velocities and detailed site descriptions are not available for most stations in Turkey.
Therefore estimate site classification by analogy with information in similar geologic materials. Obtain type
of geologic material in number of ways: consultation with geologists at Earthquake Research Division of
Ministry of Public Works and Settlement, various geological maps, past earthquake reports and geological
references prepared for Turkey.
- Only used records from small earthquakes recorded at closer distances than large earthquakes to minimize
the influence of regional differences in attenuation and to avoid the complex propagation effects coming
from longer distances.
- Only use records from earthquakes with Mw ≳ 5.0 to emphasize ground motions of engineering significance
and to limit analysis to more reliably recorded earthquakes.
- During regression lock magnitudes within ±0.25 magnitude unit bands centred at halves or integer
magnitudes to eliminate errors coming from magnitude determination.
- Note that use of epicentral distance for small earthquakes does not introduce significant bias because
dimensions of rupture area of small earthquakes are usually much smaller than distance to recording
- Examine peak ground motions from the small number of normal- (14 records) and reverse-faulting (6
records) earthquakes in set and find that they were not significantly different from ground motions from
strike-slip earthquakes (73 records). Therefore combine all data.
- Records mainly from small buildings built as meteorological stations up to three stories tall. Note that
this modifies the recorded accelerations and hence increases the uncertainty.
- Exclude data from aftershocks (mainly of the Kocaeli and Duzce earthquakes) because it was from free-field
stations and did not want to mix it with the data from the non-free-field records.
- Exclude a few records for which PGA of mainshock is ≲ 0.04g.
- Note that there is limited data and the data is poorly distributed. Also note that there is near-total lack
of knowledge of local geology and that some of the records could be affected by the building in which the
instrument was housed.
- More than half the records (49 records, 53% of total) are from two Mw > 7 earthquakes (Kocaeli and
Duzce) so the results are heavily based on the ground motions recorded in these two earthquakes.