Search results for " seismic tomography"
showing 6 items of 6 documents
3-D attenuation image of fluid storage and tectonic interactions across the Pollino fault network
2021
SUMMARYThe Pollino range is a region of slow deformation where earthquakes generally nucleate on low-angle normal faults. Recent studies have mapped fault structures and identified fluid-related dynamics responsible for historical and recent seismicity in the area. Here, we apply the coda-normalization method at multiple frequencies and scales to image the 3-D P-wave attenuation (QP) properties of its slowly deforming fault network. The wide-scale average attenuation properties of the Pollino range are typical for a stable continental block, with a dependence of QP on frequency of $Q_\mathrm{ P}^{-1}=(0.0011\pm 0.0008) f^{(0.36\pm 0.32)}$. Using only waveforms comprised in the area of seism…
Study of Southern Tyrrhenian and Sicilian regions by a sequential procedure to integrate WAM seismic tomographies and Bouguer anomaly data
2009
A procedure to obtain 3D velocity-density models and earthquake relocation by integrated inversion of P and S wave traveltimes and Bouguer anomaly distribution was applied to a large dataset concerning the Southern Tyrrhenian and Sicilian areas. The seismic dataset was subdivided into two subsets for separate inversions, whose results were later on joined by the WAM (Weighted Average Model) technique. This is a post-processing technique proposed by Calò et al. (2009) by which preliminary tomographic models are unified in a common 3D grid. The first dataset concerns 28873 P and 9990 S arrival times of 1800 earthquakes located in the area 14°30′ E - 17°E, 37°N - 41°N while the second dataset …
Sequential techique for joint inversion of gravimetric and seismic data applied to the Sicilian area
2009
Understanding seismic path biases and magmatic activity at Mount St Helens volcano before its 2004 eruption
2020
SUMMARY In volcanoes, topography, shallow heterogeneity and even shallow morphology can substantially modify seismic coda signals. Coda waves are an essential tool to monitor eruption dynamics and model volcanic structures jointly and independently from velocity anomalies: it is thus fundamental to test their spatial sensitivity to seismic path effects. Here, we apply the Multiple Lapse Time Window Analysis (MLTWA) to measure the relative importance of scattering attenuation vs absorption at Mount St Helens volcano before its 2004 eruption. The results show the characteristic dominance of scattering attenuation in volcanoes at lower frequencies (3–6 Hz), while absorption is the primary atte…