Small-Scale Volcanic Structures of the Aeolian Volcanic Arc Revealed by Seismic Attenuation

Castro-Melgar, Ignacio; Prudencio, Janire; Cannata, Andrea; Pezzo, Edoardo Del; Ibáñez, Jesús M.

doi:10.3389/feart.2021.725402

Cited by 3 publications

References 83 publications

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Depth and Spatial Variation of the Shear Wave Attenuation Parameters in the Shallow Crust and Lower Crust/Upper Mantle of Mt. Etna (Italy)

Giampiccolo,

Tuvè,

Bianco

et al. 2024

Pure Appl. Geophys.

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Seismic wave attenuation is a key feature of seismic wave propagation that provides constraints on the composition and physical state of the medium within the Earth. We separated intrinsic and scattering attenuation coefficients for the shallow crust and lower crust/upper mantle in the Mt. Etna area. For this purpose, the Multiple Lapse Time Window Analysis (MLTWA) was applied to two groups of earthquakes, well separated in depth. We also studied the spatial variation of the attenuation parameters by dividing the study area into four sectors around Etna. The results show an effective homogeneity of the propagation characteristics inside Etna and, in particular, some lateral variations and minor variations with depth. We observe that structural discontinuities and lithology control scattering losses at all frequencies, with higher scattering in the shallow crust. The intrinsic absorption shows no sensitivity to the presence of these main geological structures and is quite uniform for different depths. Furthermore, compared to the northern sector of the volcano, the southern one shows stronger scattering attenuation at low frequencies. This pattern correlates well with the high seismic activity along most of Etna’s active tectonic structures and ascending magmatic fluids that characterize this sector of the volcano. Although we only discuss the differences in the "average" scattering and inelastic properties of the investigated volumes, the results of this study are very informative about the characteristics of each region. Moreover, they suggest that a future study is necessary, providing a more detailed picture of the spatial distribution of seismic attenuation in the study area, through a 3D inversion of the attenuation parameters estimated along the single source-receiver paths.

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Depth and Spatial Variation of the Shear Wave Attenuation Parameters in the Shallow Crust and Lower Crust/Upper Mantle of Mt. Etna (Italy)

Giampiccolo,

Tuvè,

Bianco

et al. 2024

Pure Appl. Geophys.

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Qβ, Qc, Qi, Qs of the Gargano Promontory (Southern Italy)

et al. 2023

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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.

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Qβ, Qc, Qi and Qs of the Gargano Promontory (Southern Italy)

Lucente

Ninivaggi

Lorenzo

et al. 2023

Preprint

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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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Small-Scale Volcanic Structures of the Aeolian Volcanic Arc Revealed by Seismic Attenuation

Cited by 3 publications

References 83 publications

Depth and Spatial Variation of the Shear Wave Attenuation Parameters in the Shallow Crust and Lower Crust/Upper Mantle of Mt. Etna (Italy)

Depth and Spatial Variation of the Shear Wave Attenuation Parameters in the Shallow Crust and Lower Crust/Upper Mantle of Mt. Etna (Italy)

Qβ, Qc, Qi, Qs of the Gargano Promontory (Southern Italy)

Qβ, Qc, Qi and Qs of the Gargano Promontory (Southern Italy)

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