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Tallarico, Andrea
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Tallarico, Andrea
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Tallarico, A.
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13 results
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- PublicationOpen Access3D-Kernel Based Imaging of an Improved Estimation of (Qc) in the Northern Apulia (Southern Italy)(2021)
; ; ; ; ; ; ; ; ; ; ; 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.49 36 - PublicationOpen AccessSeismic Envelopes of Coda Decay for Q-coda Attenuation Studies of the Gargano Promontory (Southern Italy) and Surrounding RegionsHere, 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.
32 23 - PublicationOpen AccessA first look at the Gargano (southern Italy) seismicity as seen by the local scale OTRIONS seismic network(2014-07)
; ; ; ; ; ;De Lorenzo, S.; Università di Bari "Aldo Moro", Dipartimento di Scienze della Terra e Geoambientali, Bari ;Romeo, A.; Università di Bari "Aldo Moro", Dipartimento di Scienze della Terra e Geoambientali, Bari ;Falco, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Michele, M.; Università di Bari "Aldo Moro", Dipartimento di Scienze della Terra e Geoambientali, Bari ;Tallarico, A.; Università di Bari "Aldo Moro", Dipartimento di Scienze della Terra e Geoambientali, Bari; ; ; ; On April 2013, a local scale seismic network, named OTRIONS, composed of twelve short period (1 Hz) three component seismometers, has been located in the northern part of the Apulia (southern Italy). In the first two months of data acquisition, the network recorded about one hundred very small (ML<2) magnitude earthquakes. A three-layer 1D VP velocity model was preliminarily computed, using the recordings of earthquakes occurred in the area in the period 2006-2012 and recorded by the national seismic network of INGV (Istituto Nazionale di Geofisica e Vulcanologia). This model was calibrated by means of a multi-scale approach, based on a global search of the minimum misfit between observed and theoretical travel times. At each step of the inversion, a grid-search technique was implemented to infer the elastic properties of the layers, by using HYPO71 to compute the forward models. In a further step, we used P and S travel times of both INGV and OTRIONS events to infer a minimum 1D VP velocity model, using a classical linearized inversion approach. Owing to the relatively small number of data and poor coverage of the area, in the inversion procedure, the VP/VS ratio was fixed to 1.82, as inferred from a modified Wadati diagram. The final 1D velocity model was obtained by averaging the inversion results arising from nine different initial velocity models. The inferred VP velocity model shows a gradual increase of P wave velocity with increasing the depth. The model is well constrained by data until to a depth of about 25-30 km.588 219 - PublicationOpen AccessSeismicity of the Gargano promontory (Southern Italy) after 7 years of local seismic network operation: Data release of waveforms from 2013 to 2018(2021-04)
; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ;; ; ; ;; The University of Bari (Italy), in cooperation with the National Institute of Geophysics and Volcanology (INGV) (Italy), has installed the OTRIONS micro-earthquake network to better understand the active tectonics of the Gargano promontory (Southern Italy). The OTRIONS network operates since 2013 and consists of 12 short period, 3 components, seismic stations located in the Apulian territory (Southern Italy). This data article releases the waveform database collected from 2013 to 2018 and describes the characteristics of the local network in the current configuration. At the end of 2018, we implemented a cloud infrastructure to make more robust the acquisition and storage system of the network through a collaboration with the RECAS-Bari computing centre of the University of Bari (Italy) and of the National Institute of Nuclear Physics (Italy). Thanks to this implementation, waveforms recorded after the beginning of 2019 and the station metadata are accessible through the European Integrated Data Archive (EIDA, https://www.orfeus-eu.org/data/eida/nodes/INGV/).295 32 - PublicationOpen AccessModeling of the steady-state temperature field in lava flows lévees(2004)
; ; ; ;Quareni, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia ;Tallarico, A.; Dipartimento di Geologia e Geofisica, Università di Bari, Italy ;Dragoni, M.; Dipartimento di Fisica, Università di Bologna, Italy; ;The rationale of lava flow deviation is to prevent major damage, and, among the possible techniques, the opening of the flow leve¤es has often been demonstrated to be suitable and reliable. The best way to open the leve¤es in the right point, in order to obtain the required effect, is to produce an explosion in situ, and it is then necessary to map with the highest precision the temperature field inside the leve¤es, in order to design a safe and successful intervention. The leve¤es are formed by lava flows due to their non-Newtonian rheology, where the shear stress is lower than the yield stress. The leve¤es then cool and solidify due to heat loss into the atmosphere. In this work we present analytical solutions of the steady-state heat conduction problem in a leve¤e using the method of conformal mapping for simple geometrical shapes of the levee cross-section (triangular or square). Numerical solutions are obtained with a finite element code for more complex, realistic geometries.235 325 - PublicationOpen AccessA first look at the Gargano (southern Italy) seismicity as seen by the local scale OTRIONS seismic network(2014-08-24)
; ; ; ; ; ;De Lorenzo, S.; Università di Bari "Aldo Moro", Dipartimento di Scienze della Terra e Geoambientali, Bari ;Romeo, A.; Università di Bari "Aldo Moro", Dipartimento di Scienze della Terra e Geoambientali, Bari ;Falco, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Michele, M.; Università di Bari "Aldo Moro", Dipartimento di Scienze della Terra e Geoambientali, Bari ;Tallarico, A.; Università di Bari "Aldo Moro", Dipartimento di Scienze della Terra e Geoambientali, Bari; ; ; ; OnApril 2013,alocal scale seismic network,namedOTRIONS, composed of twelve short period (1 Hz) three component seismometers, has been located in the northern part of the Apulia (Southern Italy). At each station, the acquisition systemallows the recording of data in situ and their real time transfer toa seismic laboratory located at the Dipartimento di Scienze della Terra e Geoambientali of Università di Bari "Aldo Moro". The preliminary real time detection and localization of the events is automatically realized by using the SeisComp3 software. In the first two months of data acquisition, the network recorded about one hundred low magnitude (ML<2) earthquakes. In that follows,wepresent the results of a study aimed at investigating the crustal structure of the Gargano promontory. To this aimweanalyzed the seismic events recorded in the area by the “Istituto Nazionale di Geofisica e Vulcanologia” (INGV) in the period 2006-2012 and the seismic events recorded by the OTRIONS network in the first two months of acquisition (march and april 2013). From the inversion of P and S travel times of INGV events we inferred a preliminary 3-layer Vp velocity model. The Moho is located at a depth of 27-30 km, in agreement with previous studies. A linearized inversion scheme that uses Velest (Kissling et al., 1994), allowed us to infer a 1D velocity model from the joint inversion of INGV and OTRIONS datasets of P and S travel times. On the whole, the number of earthquakes recorded by the OTRIONS seismic network is higher than 1200 in the period april,2013-march,2014.324 505 - PublicationOpen AccessSeismogenic Structure Orientation and Stress Field of the Gargano Promontory (Southern Italy) From Microseismicity Analysis(2021-04)
; ; ; ; ; ; ; ; ; ; ; Historical seismic catalogs report that the Gargano Promontory (southern Italy) was affected in the past by earthquakes with medium to high estimated magnitude. From the instrumental seismicity, it can be identified that the most energetic Apulian sequence occurred in 1995 with a main shock of MW = 5.2 followed by about 200 aftershocks with a maximum magnitude of 3.7. The most energetic earthquakes of the past are attributed to right-lateral strike-slip faults, while there is evidence that the present-day seismicity occur on thrust or thrust-strike faults. In this article, we show a detailed study on focal mechanisms and stress field obtained by micro-seismicity recorded from April 2013 until the present time in the Gargano Promontory and surrounding regions. Seismic waveforms are collected from the OTRIONS Seismic Network (OSN), from the Italian National Seismic Network (RSN), and integrated with data from the Italian National Accelerometric Network (RAN) in order to provide a robust dataset of earthquake localizations and focal mechanisms. The effect of uncertainties of the velocity model on fault plane solutions (FPS) has been also evaluated indicating the robustness of the results. The computed stress field indicates a deep compressive faulting with maximum horizontal compressive stress, SHmax, trending NW-SE. The seismicity pattern analysis indicates that the whole crust is seismically involved up to a depth of 40 km and indicates the presence of a low-angle seismogenic surface trending SW-NE and dipping SE-NW, similar to the Gargano–Dubrovnik lineament. Shallower events, along the eastern sector of the Mattinata Fault (MF), are W-E dextral strike-slip fault. Therefore, we hypothesized that the seismicity is locally facilitated by preexisting multidirectional fractures, confirmed by the heterogeneity of focal mechanisms, and explained by the different reactivation processes in opposite directions over the time, involving the Mattinata shear zone.59 63 - PublicationOpen AccessRole of crustal fluids and thermo-mechanical structure for lower crustal seismicity: The Gargano Promontory (southern Italy)(2022-09)
; ; ; ; ; ; ; ; ;; ; Several regions around the globe are characterized by a seismically active lower crust, at depths where lithological and thermal conditions suggest stress release by ductile flow. The Gargano Promontory (GP, southern Italy) is an example where a recently installed seismic network has recorded an intense seismic activity at depths between 20 and 30 km, i.e. in the lower crust. The GP is located in proximity of the Gargano-Dubrovnik lineament, a seismogenic zone separating the central and southern Adriatic basins. These two basins constitute sites of sediments accumulation since Tertiary times. Another important basin in the region is represented by the Apennine foredeep, that includes the Candelaro area. We analyze the possible mechanisms controlling the distribution of seismicity in the GP to identify the factors that make the lower crust seismically active. To this aim, we construct a thermo-rheological model of a layered continental crust, calibrated on the basis of geometrical, lithological and thermal constraints. The model takes into account various crustal lithologies, the presence of fluids in the crystalline basement, lateral variations of geotherm and stress field. The numerical simulations show that the presence of fluids is a key factor controlling the cluster of seismicity in the lower crust. Moreover, the presence of water in the upper crystalline basement and sedimentary cover provides a plausible explanation for upper crustal seismicity in a zone of very high heat flow SW of the GP. The distribution of the seismicity is probably affected by the composition of the crystalline basement, with mafic bodies injected into the crust during the Paleocene magmatic phase that affected the Mediterranean region. In addition, fluid accumulation and overpressure may occur along detachment levels in the lower crust, leading to clustering of the earthquakes. Based on our findings, we hypothesize that the presence of hydrous diapiric upwelling(s) in the upper mantle can feed a deep fluid circulation system, inducing lower crustal seismicity.114 4 - PublicationOpen AccessQβ, Qc, Qi, Qs of the Gargano Promontory (Southern Italy)(2023-08)
; ; ; ; ; ; ; ;; ;; ; ;We have provided the first estimate of scat- tering and intrinsic attenuation for the Gargano Prom- ontory (Southern Italy) analyzing 190 local earthquakes with M L ranging from 1.0 to 2.8. To separate the intrin- sic Q i and scattering Q s quality factors with the Wen- nerberg approach (1993), we have measured the direct S waves and coda quality factors ( Q 𝛽 , Q c ) in the same volume of crust. Q 𝛽 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 = 1.5T 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 pre- dominance 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 previ- ously 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 earth- quake foci fall in high Q i areas, indicating lower level of anelastic dumping and a brittle behavior of rocks.39 10 - PublicationRestrictedConditions for crust and tube formation in lava flows with power-law rheology(2011)
; ; ; ;Filippucci, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Tallarico, A. ;Dragoni, M.; ;We studied the conditions of crust and tube formation of a lava flow moving under the effect of gravity in a rectangular cross-section channel and assumed a power-law rheology for lava. We followed the work of Valerio et al. (2008), who studied the effect of surface cooling on the formation and accretion of the crust in the central region of the channel, assuming for lava a Newtonian rheology. According to these authors, tube formation is influenced by topography and channel morphology. In this work, we extended this study to a non-Newtonian rheology, in particular to the power-law rheology. Results indicate that a power-law rheology strongly influences the condition of crust formation but does not produce significant differences as a function of topographical or morphological variations.209 25