- Ground-motion model is:
where y is in cm∕s2; a = 1.344, b = 0.328, c = -1.09, h = 5, e0 = 0, e1 = 0.262, e2 = 0.096 and σ = 0.32
using repi; and a = 1.954, b = 0.193, c = -1.01, h = 5.88, e0 = 0, e1 = 0.264, e2 = 0.144 and σ = 0.300
- Use three site classes following Sabetta and Pugliese (1987, 1996):
- Rock: rock outcrops or deposits thinner than 5m. 95 records. S1 = 1 and S2 = S3 = 0.
- Shallow alluvium: deposits thinner than or equal to 20m and thicker than 5m. V s of alluvium between
400 and 800m∕s. 61 records. S2 = 1 and S1 = S3 = 0.
- Deep alluvium: deposits thicker than 20m. 79 records. S3 = 1 and S1 = S2 = 0.
Site classification performed using verified geological, geophysical and geotechnical information, which
altered the previous categorization of some stations. Data from 137 different stations.
- Focal depths from 2 to 29km.
- Use data from Italian Accelerometric Archive (ITACA) from between 1972 and 2002, which have been
carefully revised during a project funded by the Italian Department of Civil Protection, plus some
data from the Northern Italy Strong Motion network (RAIS). Records individually processed. Analogue
records corrected for linear trend and instrument response and then band-pass filtered, selecting high-pass
frequency from visual inspection of Fourier spectra (generally between 0.3 and 0.5Hz) and low-pass
frequency chosen close to instrument frequency (generally between 20 and 25Hz). Digital records corrected
for linear trend using entire trace (because few records have usable pre-event portion) and then band-pass
filtered in the same way as analogue data (but with generally lower cut-offs, 0.1–0.3Hz and 25–30Hz).
Use raised cosine filter for analogue records, which often triggered on S-phase, and acausal fourth-order
Butterworth for digital signals, which were padded with zeros at both ends. Find PGAs are consistent
with those of Sabetta and Pugliese (1987, 1996) for common records.
- Very similar data to that used by Bindi et al. (2009a) (see Section 2.308).
- State that GMPEs are updates of those by Sabetta and Pugliese (1987, 1996).
- Examine goodness of fit of the GMPEs of Sabetta and Pugliese (1987, 1996) to the data and find that
they do not adequately fit because of a too small σ and non-zero bias. Therefore, derive new GMPEs.
- Use the data from the 17 earthquakes used by Sabetta and Pugliese (1987, 1996) plus data from ten
events that occurred from 1990 to 2002 with Mw > 5.3 and one earlier shock (Ancona 1972) that was not
used by Sabetta and Pugliese (1987, 1996).
- Most new earthquakes on normal faults in central and southern Apennines with a few on strike-slip faults.
- Best sampled areas are: eastern Alps (Friuli), central-southern Apennines from Marche to Pollino and
north and east Sicily.
- Majority of earthquakes recorded by more than four stations (minimum two, maximum 24).
- For Irpinia mainshock (23/11/1980), which is composed of three sub-events, used magnitude, location and
time-histories of first sub-event because it can be clearly recognized.
- Only seven records from < 5km. Earthquakes with Mw > 6 recorded at distances > 20km. Best-sampled
interval is 10–100km and Mw5–6.
- Compare observed and predicted PGAs for Mw5.5 and 6.9 and find good agreement.
- Calculate inter-event and inter-station residuals and relate observed large under- or over-estimation
for particular events to deep focal depths or other source characteristics. Compute σeve = 0.174 and
σsta = 0.222 as inter-event and inter-station standard deviations.
- Repeat regression using 17 earthquakes of Sabetta and Pugliese (1987, 1996) but including data from
additional stations that were not used by Sabetta and Pugliese (1987, 1996) and using the updated site
classes. Find significant differences for Mw6.5 at 20km.