Here, we describe the dataset of seismic envelopes used to study the S-wave Q-coda attenuation quality factor Qc of the Gargano Promontory (Southern Italy). With this dataset, we investigated the crustal seismic attenuation by the Qc parameter. We collected this dataset starting from two different earthquake catalogues: the first regarding the period from April 2013 to July 2014; the second regarding the period from July 2015 to August 2018. Visual inspection of the envelopes was carried out on recordings filtered with a Butterworth two-poles filter with central frequency fc = 6 Hz. The obtained seismic envelopes of coda decay can be linearly fitted in a bilogarithmic diagram in order to obtain a series of single source-receiver measures of Qc for each seismogram component at different frequency fc. The analysis of the trend Qc(fc) gives important insights into the heterogeneity and the anelasticity of the sampled Earth medium.

We investigate crustal seismic attenuation by the coda quality parameter (Qc) in the Gargano area (Southern Italy), using a recently released dataset composed of 191 small earthquakes (1.0 ≤ ML ≤ 2.8) recorded by the local OTRIONS and the Italian INGV seismic networks, over three years of seismic monitoring. Following the single back-scattering theoretical assumption, Qc was computed using different frequencies (in the range of 2–16 Hz) and different lapse times (from 10 to 40 s). The trend of Qc vs. frequency is the same as that observed in the adjacent Umbria-Marche region. Qc at 1 Hz varies between 11 and 63, indicating that the area is characterized by active tectonics, despite the absence of high-magnitude earthquakes in recent decades. The 3D mapping procedure, based on sensitivity kernels, revealed that the Gargano Promontory is characterized by very low and homogeneous Qc at low frequencies, and by high and heterogeneous Qc at high frequencies. The lateral variations of Qc at 12 Hz follow the trend of the Moho in this region and are in good agreement with other geophysical observations.

We have provided the first estimate of scattering and intrinsic attenuation for the Gargano Promontory (Southern Italy) analyzing 190 local earthquakes with ML ranging from 1.0 to 2.8. To separate the intrinsic $${Q}_{i}$$ Q i and scattering $${Q}_{s}$$ Q s quality factors with the Wennerberg approach (1993), we have measured the direct S waves and coda quality factors ($${Q}_{\beta }$$ Q β , $${Q}_{c}$$ Q c ) in the same volume of crust. $${Q}_{\beta }$$ Q β parameter is derived with the coda normalization method (Aki 1980) and $${Q}_{c}$$ Q c factor is derived with the coda envelope decay method (Sato 1977). We selected the coda envelope by performing an automatic picking procedure from $${T}_{\mathrm{start}}=1.5{T}_{S}$$ T start = 1.5 T S up to 30 s after origin time (lapse time $${T}_{L}$$ T L ). All the obtained quality factors clearly increase with frequency. The $${Q}_{c}$$ Q c values correspond to those recently obtained for the area. The estimated $${Q}_{i}$$ Q i are comparable to the $${Q}_{c}$$ Q c at all frequencies and range between 100 and 1000. The $${Q}_{s}$$ Q s parameter shows higher values than $${Q}_{i}$$ Q i , except for 8 Hz, where the two estimates are closer. This implies a predominance of intrinsic attenuation over the scattering attenuation. Furthermore, the similarity between $${Q}_{i}$$ Q i and $${Q}_{c}$$ Q c allows us to interpret the high $${Q}_{c}$$ Q c anomaly previously found in the northern Gargano Promontory up to a depth of 24 km, as a volume of crust characterized by very low seismic dumping produced by conversion of seismic energy into heat. Moreover, most of the earthquake foci fall in high $${Q}_{i}$$ Q i areas, indicating lower level of anelastic dumping and a brittle behavior of rocks.

We have provided the first estimate of scattering and intrinsic attenuation for the Gargano Promontory (Southern Italy) analyzing 190 local earthquakes with ML ranging from 1.0 to 2.8. To separate the intrinsic \({Q}_{i}\) and scattering \({Q}_{s}\) quality factors with the Wennerberg approach (1993), we have measured the direct S waves and coda quality factors (\({Q}_{\beta }\), \({Q}_{c}\)) in the same volume of crust. \({Q}_{\beta }\) parameter is derived with the coda normalization method (Aki, 1980) and \({Q}_{c}\) factor is derived with the coda envelope decay method (Sato, 1977). We selected the coda envelope by performing an automatic picking procedure from \({T}_{start}=1.5{T}_{S}\) up to 30 s after origin time (lapse time \({T}_{L}\)). All the obtained quality factors clearly increase with frequency. The \({Q}_{c}\) values correspond to those recently obtained for the area. The estimated \({Q}_{i}\) are comparable to the \({Q}_{c}\) at all frequencies and range between 100 and 1000. The \({Q}_{s}\) parameter shows higher values than \({Q}_{i}\), except for 8 Hz, where the two estimates are closer. This implies a predominance of intrinsic attenuation over the scattering attenuation. Furthermore, the similarity between \({Q}_{i}\) and \({Q}_{c}\) allows us to interpret the high \({Q}_{c}\) anomaly previously found in the northern Gargano Promontory up to a depth of 24 km, as a volume of crust characterized by very low seismic dumping produced by conversion of seismic energy into heat. Moreover, most of the earthquake foci fall in high \({Q}_{i}\) areas, indicating lower level of anelastic dumping and a brittle behavior of rocks.

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