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Tosi, Patrizia
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Tosi, Patrizia
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patrizia.tosi@ingv.it
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staff
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7103207181
37 results
Now showing 1 - 10 of 37
- PublicationOpen AccessInfluence of strong electromagnetic discharges on the dynamics of earthquakes time distribution in the Bishkek test area (Central Asia)(2006-08)
; ; ; ; ;Chelidze, T.; Institute of Geophysics, Georgian Academy of Sciences, Tbilisi, Georgia ;De Rubeis, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Matcharashvili, T.; Institute of Geophysics, Georgian Academy of Sciences, Tbilisi, Georgia ;Tosi, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; ; ; From 08/01/1983 to 28/03/1990, at the Bishkek ElectroMagnetic (EM) test site (Northern Tien Shan and Chu Valley area, Central Asia), strong currents, up to 2.5 kA, were released at a 4.5 km long electrical (grounded) dipole. This area is seismically active and a catalogue with about 14100 events from 1975 to 1996 has been analyzed. The seismic catalogue was divided into three parts: 1975-1983 first part with no EM experiments, 1983-1990 second part during EM experiments and 1988-1996 after experiments part. Qualitative and quantitative time series non- linear analysis was applied to waiting times of earthquakes to the above three sub catalogue periods. The qualitative approach includes visual inspection of reconstructed phase space, Iterated Function Systems (IFS) and Recurrence Quantification Analysis (RQA). The quantitative approach followed correlation integral calculation of reconstructed phase space of waiting time distribution, with noise reduction and surrogate testing methods. Moreover the Lempel- Ziv algorithmic complexity measure (LZC) was calculated. General dynamics of earthquakes’ temporal distribution around the test area, reveals properties of low dimensional non linearity. Strong EM discharges lead to the increase in extent of regularity in earthquakes temporal distribution. After cessation of EM experiments the earthquakes’ temporal distribution becomes much more random than before experiments. To avoid non valid conclusions several tests were applied to our data set: differentiation of the time series was applied to check results not affected by non stationarity; the surrogate data approach was followed to reject the hypothesis that dynamics belongs to the colored noise type. Small earthquakes, below completeness threshold, were added to the analysis to check results robustness.243 366 - PublicationOpen AccessWeb-based macroseismic survey: fast information exchange and elaboration of seismic intensity effects in Italy(2009-12)
; ; ; ; ;De Rubeis, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Sbarra, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Tosi, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Sorrentino, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; ; ; A new method of macroseismic survey, based on voluntary collaboration through the internet, has been running at Istituto Nazionale di Geofisica e Vulcanologia (INGV), Italy, since June 2007. The macroseismic questionnaire is addressed to a single nonspecialist person and reported effects are statistically analysed to extrapolate the Mercalli-Cancani-Sieberg (MCS) scale and the European Macroseismic Scale (EMS) intensity referred to by that observer. Maps of macroseismic intensity are displayed online in almost real time and are continuously updated. The aim of the questionnaire is to evaluate seismic effects as felt by the compiler. The final result is a definition of a particular degree of intensity with an evaluation of an associated uncertainty. Results of medium to low magnitude earthquakes are presented here, showing the ability of the method to give fast and interesting results. Effects reported in questionnaires coming from towns are analysed in-depth and assigned intensities are compared with those derived from traditional macroseismic surveys, showing the reliability of the web-based method.999 214 - PublicationOpen AccessLocal seismicity in Rome (Italy): recent results from macroseismic evidences(1996-12)
; ; ; ;Tertulliani, A.; Istituto Nazionale di Geofisica, Roma, Italy ;Tosi, P.; Istituto Nazionale di Geofisica, Roma, Italy ;De Rubeis, V.; Istituto Nazionale di Geofisica, Roma, Italy; ; This paper presents the results obtained from the study of the macroseismic effects of the June 12, 1995 Rome earthquake. The event, MD = 3.8, provoked VI degree MCS effects in neighbourhoods of Southern Rome. This earthquake is important within the framework of seismicity in the Rome area, as it is the first noteworthy one ever to be recorded in the instrumental age, and provides a good comparison with historical earthquakes which have occurred in the same area. The filtering procedure performed on the macroseismic field reveals out the anomalies of the attenuation pattern and the site effect. The results reconfirm what has only recently emerged from the analysis of historical earthquakes, i.e. Rome is affected by local seismicity, that can cause damage in the southern neighbourhoods and the downtown area, especially where the site contributes to the amplification of the effects.149 244 - PublicationOpen AccessIs an Earthquake Felt Inside a Car?(2021-02-17)
; ; ; ; ; ; ; The analysis of how an earthquake is felt was addressed with the data provided by citizens through a website dedicated to the perception of earthquakes in Italy (Data and Resources). The analysis focused on the perception of earthquakes by observers inside both parked and moving cars. These situations were compared with outdoor ones. The felt percentage of each situation was quantified for epicentral distance ranges and European Macroseismic Scale (EMS) degree. One of the main findings was the greatest sensitivity to shaking for people inside parked cars due to resonance phenomena of the automobile–observer system. The distribution of the intensity of perception in the car was analyzed as a function of the hypocentral distance and the magnitude of the earthquake. It was possible to define the attenuation trends of these intensities. The comparison of these trends with those of the equations for estimation of response spectral ordinates allowed us to have an evaluation of the frequency values of the seismic waves that caused the vibrations felt, which were found to agree with the typical frequencies of the car–observer system, as highlighted by independent studies. The results of this analysis show the possibility to include the perception of the earthquake inside a parked and moving car among the diagnostics used in the definition of macroseismic intensity degree of the EMS.145 127 - PublicationOpen AccessSpace-time combined correlation integral and earthquake interactions(2004)
; ; ; ; ;Tosi, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;De Rubeis, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Loreto, V.; Centro INFM di Meccanica Statistica e Complessità, Università La Sapienza, Roma, Italy ;Pietronero, L.; Centro INFM di Meccanica Statistica e Complessità, Università La Sapienza, Roma, Italy; ; ; Scale invariant properties of seismicity argue for the presence of complex triggering mechanisms. We propose a new method, based on the space-time combined generalization of the correlation integral, that leads to a self-consistent visualization and analysis of both spatial and temporal correlations. The analysis has been applied on global medium-high seismicity. Results show that earthquakes do interact even on long distances and are correlated in time within defined spatial ranges varying over elapsed time. On that base we redefine the aftershock concept.183 284 - PublicationOpen AccessStacked analysis of earthquake sequences: statistical space-time definition of clustering and Omori law behavior(2010)
; ; ; ;Tosi, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;De Rubei, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Sbarra, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; ; ; ; ; ;De Rubeis, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Teisseyre, R.The definition of the aftershocks sequence is still a debated topic. We here propose a study of the spatial and temporal variation of the earthquakes clustering and rate decay. We used five different seismic catalogues, characterized by specific spatial and magnitude ranges. They are respectively: world one, for a global analysis, Greek, Japanese, Californian and Italian regional catalogues in order to investigate different seismo-tectonic settings. A stacking procedure has been applied to characterize a typical sequence behavior and allowing the evaluation of changes over time intervals (107 296 - PublicationOpen AccessQuantification of earthquake diagnostic effects to assess low macroseismic intensities(2020)
; ; ; ; ; ; ; A large amount of data about earthquake effects, supplied by citizens through a web-based questionnaire, enabled the analysis of the occurrence of many of the effects on humans and objects listed in macroseismic scales descriptions. Regarding the other diagnostic effects (rattling, moving, shifting, falling or overturning depending of the object type of doors, windows, china, glasses, small objects, pictures, vases, books, as well as frightened peo- ple and animal behaviour), data from more than 300,000 questionnaires about earthquakes felt in Italy from June 2007 to August 2017, were analysed by stacking them together as a function of hypocentral distance and magnitude. The comparison of the resulting percent- ages with the intensity prediction equation showed that almost all the chosen effects are good diagnostics for macroseismic intensity evaluation, as their percentages are well dif- ferentiated. We did not analyse the oscillations of hanging objects and liquids because the differences in effect attenuations, highlighted by the maps of the occurrence percentage, suggested to not consider them as diagnostic effect. This result allowed us to quantify the occurrence of each diagnostic effect for the intensity degrees from II to VI of the European macroseismic scale for the people who felt the earthquake. The application of the intensity assessment method to internet macroseismic data, based on the specifications herein pro- posed, should mitigate the problem of “not felt” undersampling in crowdsourced web data.199 38 - PublicationOpen AccessMacroseismic effects highlight site response in Rome and its geological signature(2012)
; ; ; ; ; ; ; ; ;Sbarra, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;De Rubeis, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Di Luzio, E.; Istituto per le Tecnologie Applicate ai Beni Culturali (ITABC) ;Mancini, M.; Istituto di Geologia Ambientale e Geoingegneria (IGAG) ;Moscatelli, M.; Istituto di Geologia Ambientale e Geoingegneria (IGAG). ;Stigliano, F.; Istituto di Geologia Ambientale e Geoingegneria (IGAG). ;Tosi, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Vallone, R; Istituto di Geologia Ambientale e Geoingegneria (IGAG).; ; ; ; ; ; ; A detailed analysis of the earthquake effects on the urban area of Rome has been conducted for the L’Aquila sequence, which occurred in April 2009, by using an on-line macroseismic questionnaire. Intensity residuals calculated using the mainshock and four aftershocks are analyzed in the light of a very accurate and original geological reconstruction of the subsoil of Rome based on a large amount of wells. The aim of this work is to highlight ground motion amplification areas and to find a correlation with the geological settings at a sub-regional scale, putting in evidence the extreme complexity of the phenomenon and the difficulty of making a simplified model. Correlations between amplification areas and both near-surface and deep geology were found. Moreover, the detailed scale of investigation has permitted us to find a correlation between seismic amplification in recent alluvial settings and subsiding zones, and between heard seismic sound and Tiber alluvial sediments.372 386 - PublicationOpen AccessEarthquake perception data highlight natural frequency details of Italian buildings(2023-04-17)
; ; ; ; ; As the distance from an earthquake increases, the percentage of people who do not feel it also increases. The average transition distance between ‘‘felt’’ and ‘‘not felt’’ reports is mainly determined by the magnitude and depth of the earthquake, but it also depends on the observation floor and building height. Buildings act as resonators and can amplify the shaking at specific frequencies.We analyzed over 286,000 crowdsourced reports to study the effect of floor and building height on earthquake perception. We found that, compared to average values, there is an increase in the percentage of ‘‘felt’’ reports on the highest floors and a decrease in the lowest floors of buildings of all heights.We determined the range within which an observer is likely to feel an earthquake (perception boundary) and examined how it varies with magnitude. We found that as the building height increases, people on higher floors perceive medium to high magnitude earthquakes progressively better than lower magnitude ones. We compared the perception boundary with a model of seismic response spectra to estimate the vibration frequency perceived by observers on each floor/ building height combination. Our results show that the value of the fundamental period increases with building height for the top floor, and that higher vibration modes become more evident for buildings with more than 6 stories. In addition, we observed that the height of the building also affects the vibration of the basement, with the frequency tending to decrease as the building height increases. Concerning macroseismic intensity estimation, we show that in tall buildings, observations made on both the upper and lower floors must be considered outside the normal range, and that earthquake perception also changes as a function of magnitude and distance, pointing out the importance of collecting an adequate number of observations to sample different locations of observers.38 8