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Calderoni, Giovanna
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Preferred name
Calderoni, Giovanna
Email
giovanna.calderoni@ingv.it
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staff
ORCID
Scopus Author ID
12040362800
Researcher ID
L-6211-2015
35 results
Now showing 1 - 10 of 35
- PublicationOpen AccessRupture directivity of the 2016, Amatrice and Norcia (central Italy) destructive earthquakes and their largest aftershocks(2017-04)
; ; ; ; ; In this study, we investigate the along-strike rupture directivity of the five moderate-magnitude (Mw > 5.0) earth- quakes of the 2016 central Italy seismic sequence and height aftershocks in the moment magnitude range from 4.4 to 4.8. Rupture directivity is estimated by deconvolving the observed spectra with spectra of EGF-type events. We have found that the August 24, Mw 6.0 Amatrice earthquake results in a bilateral along-strike rupture. How- ever, directivity of this event is asymmetrical, the predominant rupture propagation being toward NNW. In contrast, the rupture of the October 30, Mw 6.5 Norcia earthquake propagated toward SSE. We have also found that the pre- dominant rupture directivity toward SSE is a common feature of the majority of the investigates events, including the Mw 5.4 aftershock occurred less than one hour after the Amatrice earthquake. Along-strike rupture directivity in normal-faulting earthquakes in the Apennines has been already documented for the three largest events of the 1997 Umbria-Marche seismic sequence and for 70 earthquakes with moment mag- nitudes from 3.0 to 6.1 of the 2009 L’Aquila-Campotosto seismic sequence (the 2016 seismic activity filled the seismic gap between them). If we put together the results of the 1997 Umbria-Marche and the 2009 earthquakes, we find a significant spatial consistency of preferred directions of ruptures. Earthquakes to the south of Colfiorito up to Norcia show directivity toward SE-SSE, similarly to earthquakes in the southern part of the Campotosto fault and in the Paganica fault. In distinct contrast, from the northern tip of the Campotosto fault up to Amatrice the predominant rupture directivity is toward NNW-NW.79 14 - PublicationOpen AccessFault-trapped waves depict continuity of the fault system responsible for the 6 April 2009 MW 6.3 L’Aquila earthquake, central Italy(2012)
; ; ; ; ; ;Calderoni, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Di Giovambattista, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Vannoli, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Pucillo, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Rovelli, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; ; ; ; We investigate fault-trapped waves observed at a permanent broad-band station (FAGN) installed on the San Demetrio Fault, about 20 km southeast of L'Aquila. This fault has the same strike of the Paganica Fault which was responsible for the MW 6.3, 6 April 2009 earthquake. The two faults display an en-echelon pattern with a few km offset. We have found that events causing efficient trapped waves are clustered at the northwestern and southeastern bottom ends of the ruptured Paganica fault plane. The efficiency of trapped waves at FAGN, which is located about 5 km far from the ruptured fault plane, indicates that the two faults are linked at depth. This suggests that fault segments in the study area can be part of a longer and continuous fault system which controls the seismic hazard of the region. Moreover, we have found that the two earthquake clusters generating the most efficient trapped waves occur in portions of the fault system with the highest fluid pressure.581 416 - PublicationOpen AccessMultidisciplinary investigations using historical data, specific experimental surveys, numerical simulations and earthquake data to assess seismic hazard in a densely urbanized city: the study case of Palermo(2005-11-01)
; ; ; ; ; ; ; ; ; ;Cara, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Cultrera, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Azzara, R. M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Calderoni, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;De Rubeis, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Di Giulio, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Giammarinaro, M. S.; Dipartimento di Geologia e Geodesia, Università di Palermo ;Vannoli, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Rovelli, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; ; ; ; ; ; ; ; The city of Palermo (southern Italy) was severely damaged in the past by moderate-magnitude earthquakes located tens of kilometres offshore. The historical monumental heritage and the high density of population motivated large efforts for the seismic risk assessment. We present the geological and seismological studies performed in downtown Palermo as a study case to show how the complexity of an urban environment can be approached with multidisciplinary investigations. Downtown Palermo is characterized by sea deposits in the coastal zone and the alluvial deposits of two rivers (Papireto and Kemonia) of about 150 m width, which were buried and filled during the XVII century. The difficulty of surface geological surveys was compensated through an analysis of aerial photos and more than 2000 borehole data organized in the City-GIS of the Department of Geology and Geodesy of the University of Palermo. A previous study on the well-documented historical damage indicated the major role played by the two river valleys and the sea deposits in controlling the damage distribution, above the assumption of a fairly homogeneous vulnerability of the existing buildings in downtown. To test the feasibility of using ambient noise for recognizing the presence of alluvial deposits in a densely urbanized environment, a large microtremor measurement campaign was performed in Palermo across several profiles. The frequency peaks inferred from the horizontal-to-vertical spectral ratio were compared with numerical simulations to assess the seismic velocity profile and the soil stratigraphy. Moreover, noise data were analyzed through a statistical approach to establish a possible correlation between damage, resonance frequency and amplitude, and geology. After the moderate earthquake of September 6, 2002 (Mw=5.9, 50 km far away), the analysis of the aftershock sequence provided a well documented estimate of the variation of ground motion within the city in the case of linear soil response. Using these aftershocks we computed also synthetic accelerograms of the main shock through Empirical Green’s Functions that provided ground accelerations as large as 50 gals, consistently with the documented EMS-98 intensity. Synthetic accelerograms showed a large variability of horizontal ground motion within the city (a factor of 3 – 4) that confirms the role of local geology in causing an increase of the seismic hazard on sea and alluvial deposits. Finally, we discuss the comparison between the acceleration response spectra calculated for different soil categories and the design elastic spectra provided by EC8.190 167 - PublicationOpen AccessSource Parameters and Radiation Efficiency in the nucleation volume of the Mw 6.1 L’Aquila Earthquake(2018-12)
; ; ; ; ; We analyze Brune stress drop and apparent stress of 25 earthquakes, mainshock, foreshocks and aftershocks, occurring in a 2.5 x 2.5 x 2.5 km 3 volume adjacent to the hypocenter of the destructive Mw 6.1 L’Aquila earthquake. In a previous paper, we used a part of these earthquakes to detect a transient anomaly of shear wave velocity in the fault zone one week before the main shock. The purpose of this study is to enlarge the previous dataset with further close earthquakes (2.2 ≤ Mw ≤ 4.1) to investigate if the same area concomitantly shows temporal and/or spatial variations in the stress parameters. Brune stress drops were computed in a conventional EGF-deconvolution approach using local seismological stations, the resulting values vary in the range 0.2 < Δσ < 8.4 MPa. Apparent stress was derived from the waveform energy corrected for propagation and site effects, it varies in the range 0.03 < a < 1.10 MPa. The ratio η sw = a / Δσ, which provides the radiation efficiency, for the largest part of the investigated earthquakes yields values close to 0.12, which is a value lower than expected for self-similar ruptures. An exception was the immediately following foreshocks and aftershocks (since a four hours before up to a four hours after the main shock, respectively) that result in values of η sw as smaller as 0.06, consistent with ruptures in seismogenic zones with high dynamic strength. The largest Δσ of these events indicates that the temporal variation is associated to a spatial variation due to the main shock asperity rupture, and a satisfactory consistency is found between the smallest and largest Δσ with the largest and smallest b-values, respectively, imaged by other authors in the nucleation volume.44 7 - PublicationOpen AccessLarge amplitude variations recorded by an on-fault seismological station during the L’Aquila earthquakes: evidence for a complex fault-induced site effect(2010-12-17)
; ; ; ;Calderoni, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Rovelli, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Di Giovambattista, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; ; This study is focused on amplification effects observed at an on-fault station, FAGN, near L’Aquila. The difference in amplitude, compared to nearby stations, is extremely large for some particular events and neigligible for others of the same seismic sequence. FAGN is located on the S. Demetrio fault (Vezzani and Ghisetti, 1998) and the presence of the fault zone beneath the station could play a role on the observed amplifications (Davis et al., 2000; Cultrera et al., 2003; Karabulut and Bouchon, 2007). The fault-guided propagation effect is investigated through numerical modeling and analytical solutions by Ben-Zion and Aki (1990) and Ben-Zion (1998).141 124 - PublicationOpen AccessSTRESS PARAMETERS OF REPEATING EARTHQUAKES IN THE NUCLEATION VOLUME OF THE APRIL 6, 2009, MW 6.1 L'AQUILA EARTHQUAKE(2018-09)
; ; ; ; ; We analyze the state of stress for 28 repeaters, foreshocks, mainshock and aftershocks, in the rupture nucleation volume of the destructive L’Aquila earthquake including the strongest Mw4.1 foreshock occurred one week before the mainshock. In a previous paper, earthquakes clustered in this crustal volume were used to detect a transient anomaly of shear wave velocity in the fault zone a ten of hours after the Mw 4.1 foreshock. The purpose of this study is to investigate whether stress parameters had concomitantly temporal or spatial variations. Brune stress drop was computed in a EGF-approach and apparent stress was derived from energy of seismograms. Estimates of individual stations and individual events showed large fluctuations, mostly due to rupture directivity and site effects. A procedure was adopted to decrease the estimate uncertainty obtaining a 39% of the total variance reduction. Brune stress drop and apparent stress showed similar trends implyingstable values of radiation efficiency around 0.23, which is the value expected for self- similarruptures. No evident temporal change emerges from the analyzed stress parameters of repeaters. In contrast, the spatial pattern of Brune stress drop shows a correlation with the b-value obtained by Sugan et al., 2014 that evidenced an asperity characterized by a low b-value on and around the nucleation zone of the mainshock.54 65 - PublicationOpen AccessRupture Directivity of the Strongest 2016-2017 Central Italy Earthquakes(2017)
; ; ; ; ; The along‐strike rupture directivity of 16 of the strongest earthquakes (4.4 ≤ Mw ≤ 6.5) within the 2016–2017 central Italy seismic sequence is estimated by investigating high‐frequency S wave amplitude variations versus source azimuths with an empirical Green's function deconvolution approach. The results confirm that an along‐strike rupture directivity is a persistent feature of normal‐faulting earthquakes in the Apennines. The preferred rupture directions of the 2016–2017 earthquakes and of similar‐magnitude events from the 1997 Umbria‐Marche and 2009 L'Aquila‐Campotosto seismic sequences show a significant spatial consistency. Different sectors of the Apennines show an alternating trend of preferential along‐strike rupture propagation directions with significant spatial and temporal stabilities independent of the magnitude. These results, if confirmed by further data, could lead to more refined hazard assessments of the investigated region.148 46 - PublicationRestrictedReport on broad-band stations on topography in Italy(2012-01-24)
; ; ; ; ; ;Pischiutta, Marta; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Vannoli, Paola; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Calderoni, Giovanna; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Pessina, Vera; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia ;Rovelli, Antonio; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; ; ; ; In Italy, a large part of the national territory is affected by significant topographic variations (grey scale variations of Fig.1). Inevitably, many stations of the Italian Seismic Network (a total of more than 250 broad-band seismological stations) are installed on topographic irregularities. The frequent seismicity of Italy (Fig. 1) produces a useful data set for a comparative study of effects caused by typical topographic shapes (e.g. ridges and cliffs). This report illustrates criteria adopted for the station selection and methods to be used in NERA for the characterization of station topography and site amplification.266 58 - PublicationOpen AccessALONG-STRIKE RUPTURE DIRECTIVITY OF THE STRONGEST CENTRAL ITALY EARTHQUAKES OCCURRED IN THE TWENTY LAST YEARS(2018-09)
; ; ; ; ; Along strike rupture directivity is a persistent feature in normal-faulting earthquakes in the Apennines. It has been already documented for many of the small to moderate magnitude events occurred in the last twenty years. In this study we extend the analysis increasing the number of the investigated earthquakes (Mw>4.0) of the 2009 L’Aquila-Campotosto and 2016-2017 Amatrice- Norcia seismic sequences. Furthermore, we selected the strongest earthquakes (Mw>3.5) occurred in the Val Tiberina area (Gubbio). The study is based on azimuthal variations of the high-frequency S wave amplitude using an empirical Green’s function deconvolution method. Our approach allows us to statistically quantify the rupture directivity of each event through a directivity index (0 < IDIR < 1) that is a measure of the spectral separation above the corner frequency of the target event at opposite along-strike directions. Depending on IDIR, source ruptures are classified as unilateral, bilateral or circular. As already observed, it is confirmed that the direction of rupture propagation is not random. Same portions of the fault system activated during the 2009 and 2016-2017sequences show a similar behaviour, with different sectors of the Apennines depicting an alternating trend of preferential along-strike rupture propagation directions. This feature, if confirmed by further data, could lead to more refined hazard assessments of the investigated region.76 15 - PublicationRestrictedOn the reliability of long period response spectral ordinates from digital accelerograms(2008)
; ; ; ; ; ; ; ; ;Paolucci, R.; Dept. of Structural Engineering, Politecnico di Milano ;Rovelli, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Faccioli, E.; Dept. of Structural Engineering, Politecnico di Milano ;Cauzzi, C.; Dept. of Structural Engineering, Politecnico di Milano ;Finazzi, D.; Dept. of Structural Engineering, Politecnico di Milano ;Vanini, M.; Dept. of Structural Engineering, Politecnico di Milano ;Di Alessandro, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Calderoni, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; ; ; ; ; ; ; Using records from co-located broad-band and digital strong motion instruments, it is first shown that the displacement waveforms obtained by double integration of the accelerogram need not be free of unrealistic baseline drift to yield reliable spectral ordinates up to at least 10 s. Secondly, to provide objective criteria for selecting reliable digital strong motion records for ground motion predictions at long periods, a set of synthetic accelerograms contaminated by random long period noise has been used and the difference between the original accelerograms and the spurious ones in terms of response spectra has been quantified, by introducing a noise index that can be easily calculated based on the velocity waveform of the record. The results of this study suggest that high-pass filtering the digital acceleration record from a cut-off period selected to suppress baseline drifts on the displacement waveform appears to be in most cases too conservative and unduly depletes reliable information on long period spectral ordinates251 1158