Rita Di Giovambattista - Academia.edu (original) (raw)

Papers by Rita Di Giovambattista

Research paper thumbnail of Rupture Directivity of the Damaging Normal Faulting Earthquakes of the Last Twenty Years in Central Apennines

Research paper thumbnail of A seismic quiescence before the 2017 Mw 7.3 Sarpol Zahab (Iran) earthquake: Detection and analysis by improved RTL method

Physics of the Earth and Planetary Interiors, 2019

A major earthquake, with magnitude Mw 7.3, struck Sarpol Zahab (Kermanshah province, Iran) on Nov... more A major earthquake, with magnitude Mw 7.3, struck Sarpol Zahab (Kermanshah province, Iran) on November 12 2017, causing extended damage and casualties. The epicentre was located in the Northwestern part of the Zagros mountain range, an active belt originated by the Arabia-Eurasia collision. We explore seismicity preceding this earthquake, by using the Iranian Seismological Center instrumental earthquake catalog (IGTU), with the aim to identify possible anomalies in background seismicity that can be related with this and other future large events. For this purpose, we used a method for intermediate term forecasts of large earthquakes, namely the Region Time Length (RTL) algorithm, which analyzes declustered catalogs and is sensitive to quiescences that may precede major earthquakes. RTL has been progressively refined and has been applied in several regions worldwide during the last decades. To decluster the earthquake catalog we used a quite novel approach, based on the nearest-neigbour distances between events in the space-time-energy domain, a method that preserves the background seismicity while removing the clustered component. The retrospective application of RTL algorithm to the area surrounding the mainshock epicenter highlights two significant quiescences: one preceding the Sarpol Zahab Mw 7.3 earthquake, and the other occurring before a Mw 5.7 earthquake, which struck the same region

Research paper thumbnail of EPSI Project Participants

Research paper thumbnail of SAFE Project: An integrated system of earthquake physics study from ground and space observations

Angelo De Santis (1), Giorgiana De Franceschi (1), Rita Di Giovambattista (1), Loredana Perrone (... more Angelo De Santis (1), Giorgiana De Franceschi (1), Rita Di Giovambattista (1), Loredana Perrone (1), Lucilla Alfonsi (1), Gianfranco Cianchini (1), Javier F. Pavón-Carrasco (1), Claudio Cesaroni (1), Luca Spogli (1), Alessandro Piscini (1), Anna De Santis (1), Giulia D’Angelo (1), Elvira Musicò (1), Andrea Malagnini (1), Leonardo Amoruso (2), Marianna Carbone (2), Cristoforo Abbattista (2), and Daniela Drimaco (2)

Research paper thumbnail of The AMR and the Revised AMR methods as diagnostic tools for the preparatory phases of large earthquakes

Research paper thumbnail of Geosystemics and Earthquakes

Geosystemics [De Santis 2009, 2014] studies the Earth system as a whole focusing on the possible ... more Geosystemics [De Santis 2009, 2014] studies the Earth system as a whole focusing on the possible coupling among the Earth layers (the so called geo-layers), and using universal tools to integrate different methods that can be applied to multi-parameter data, often taken on different platforms. Its main objective is to understand the particular phenomenon of interest from a holistic point of view. In this paper we will deal with earthquakes, considered as a long term chain of processes involving, not only the interaction between different components of the Earth's interior, but also the coupling of the solid earth with the above neutral and ionized atmosphere, and finally culminating with the main rupture along the fault of concern [De Santis et al., 2015a]. Some case studies (particular emphasis is given to recent central Italy earthquakes) will be discussed in the frame of the geosystemic approach for better understanding the physics of the underlying complex dynamical system.

Research paper thumbnail of Possible Lithosphere-Atmosphere-Ionosphere Coupling effects prior to the 2018 Mw = 7.5 Indonesia earthquake from seismic, atmospheric and ionospheric data

Journal of Asian Earth Sciences, 2019

In this study, we analyse Lithosphere Atmosphere Ionosphere Coupling (LAIC) effects to identify s... more In this study, we analyse Lithosphere Atmosphere Ionosphere Coupling (LAIC) effects to identify some phenomena that could, possibly, be linked to the preparation phase of the M W = 7.5 earthquake occurred in Indonesia on September 28th, 2018, by investigating the eight months preceding the seismic event. First, we find a seismic acceleration that started two months before the mainshock. Then, studying some physical properties of the atmosphere (skin temperature, total column water vapor and aerosol optical thickness), we find two increases of atmospheric anomalies about 6 and 3.7 months before the mainshock, and the latter one is very promising as a candidate for seismic-related phenomena. Furthermore, we investigate ionospheric disturbances, by analysing the Swarm and, for the first time, China Seismo-Electromagnetic Satellite (CSES), magnetic and electron density data during quiet geomagnetic time. From different techniques, we find interesting anomalies concentrated around 2.7 months before the mainshock. On August 19th, 2018, Swarm and CSES showed an enhancement of the electron density during night time. We critically discuss the possibility that such phenomenon can be a possible pre-seismic-induced ionospheric effect. Finally, we performed a cumulative analysis using all detected anomalies, as a test case for a possible chain of physical phenomena that could happen before the earthquake occurrence. With this study, we support the usefulness to collect and store large Earth ground and satellite observational dataset that in the future could be useful to monitor in real time the seismic zones to anticipate earthquakes, although nowadays, there is no evidence about useful prediction capabilities.

Research paper thumbnail of Strong following earthquake forecasting by a pattern recognition approach in California 

Research paper thumbnail of Seismicity and stress field in the Sannio-Matese area

In this study we discuss the available data on seismicity and focal mechanisms in the Sannio-Mate... more In this study we discuss the available data on seismicity and focal mechanisms in the Sannio-Matese area in order to obtain information on the stress field acting in the area. Background seismicity of the area is characterized by isolated events, with magnitude generally less than 2.5, on which is superimposed a swarm and seismic sequence activity of low magnitude (max magnitude 4.1). The epicentral distribution of both isolated events and seismic sequences, disclose NE-SW striking active faults that fall in between the fault segments of the large historical earthquakes which occurred in the area. The available information on the stress field deducible from the focal mechanisms of the area agrees that a general extensional stress regime is acting. Locally both NE-SW and NNW-SSE extensions are observed. The large scale stress regime deduced from the focal mechanisms of strong instrumental earthquakes which occurred in the Apennines supports the local NE-SW extension but cannot explain the normal movements related to a NW-SE extension. The local longitudinal extension observed, supported by GPS data, can be explained utilizing large scale geodynamic models.

Research paper thumbnail of Large amplitude variations recorded by an on-fault seismological station during the L'Aquila earthquakes: Evidence for a complex fault-induced site effect

Geophysical Research Letters, 2010

Motivation: One station, FAGN, installed on a segment of the fault system that generated the Apri... more Motivation: One station, FAGN, installed on a segment of the fault system that generated the April 2009 earthquakes, shows anomalously larger ground motions compared the nearby stations.

Research paper thumbnail of Seismic and geodetic evidences of a hydrothermal source in the M d 4.0, 2017 Ischia earthquake (Italy)

Journal of Geophysical Research: Solid Earth

Research paper thumbnail of 3 Seismicity and stress field in the Sannio-Matese area

In this study we discuss the available data on seismicity and focal mechanisms in the Sannio-Mate... more In this study we discuss the available data on seismicity and focal mechanisms in the Sannio-Matese area in or-der to obtain information on the stress field acting in the area. Background seismicity of the area is character-ized by isolated events, with magnitude generally less than 2.5, on which is superimposed a swarm and seismicsequence activity of low magnitude (max magnitude 4.1). The epicentral distribution of both isolated events andseismic sequences, disclose NE-SW striking active faults that fall in between the fault segments of the large his-torical earthquakes which occurred in the area. The available information on the stress field deducible from thefocal mechanisms of the area agrees that a general extensional stress regime is acting. Locally both NE-SW andNNW-SSE extensions are observed. The large scale stress regime deduced from the focal mechanisms of stronginstrumental earthquakes which occurred in the Apennines supports the local NE-SW extension but cannot ex-plain...

Research paper thumbnail of Stress drop, apparent stress, and radiation efficiency of clustered earthquakes in the nucleation volume of the April 6, 2009, M w 6.1 L'Aquila earthquake

Journal of Geophysical Research: Solid Earth

Research paper thumbnail of Spatio-temporal variations of source parameters in the nucleation zone of the 6 April 2009, Mw 6.1 L'Aquila Earthquake

&... more <p>We present the results of Brune stress drop (∆σ) and apparent stress (τa) variability of  earthquakes located in a small zone adjacent to the hypocenter of the damaging Mw 6.1 L'Aquila earthquake. Their magnitude ranges between  2.7 and 4.1. Interevent variability of stress drop and apparent stress results in a factor of 10, well beyond the individual‐event uncertainty. Radiation efficiency ηsw = τa/∆σ varies mostly between 0.1 and 0.2, but decreases in the days immediately before and after the main shock to values as low as 0.06. This may be related to the migration of the events occurring in those days into a focal volume with higher dynamic strength. The temporal change of ηsw might be interpreted as a spatial variation due to the earthquake migration into the locked portion of the fault originating the main shock. Furthermore, no variation in stress drop and apparent stress can be observed between foreshocks and aftershocks but the smallest and largest ∆σ result in a good correlation with the largest and smallest b‐values respectively, as already documented in literature in the rupture nucleation volume of large earthquakes.</p>

Research paper thumbnail of Revised Accelerated Moment Release Under Test: Fourteen Worldwide Real Case Studies in 2014–2018 and Simulations

Pure and Applied Geophysics

Research paper thumbnail of Geosystemics View of Earthquakes

Entropy

Earthquakes are the most energetic phenomena in the lithosphere: their study and comprehension ar... more Earthquakes are the most energetic phenomena in the lithosphere: their study and comprehension are greatly worth doing because of the obvious importance for society. Geosystemics intends to study the Earth system as a whole, looking at the possible couplings among the different geo-layers, i.e., from the earth’s interior to the above atmosphere. It uses specific universal tools to integrate different methods that can be applied to multi-parameter data, often taken on different platforms (e.g., ground, marine or satellite observations). Its main objective is to understand the particular phenomenon of interest from a holistic point of view. Central is the use of entropy, together with other physical quantities that will be introduced case by case. In this paper, we will deal with earthquakes, as final part of a long-term chain of processes involving, not only the interaction between different components of the Earth’s interior but also the coupling of the solid earth with the above ne...

Research paper thumbnail of Magnetic Field and Electron Density Data Analysis from Swarm Satellites Searching for Ionospheric Effects by Great Earthquakes: 12 Case Studies from 2014 to 2016

Atmosphere

We analyse Swarm satellite magnetic field and electron density data one month before and one mont... more We analyse Swarm satellite magnetic field and electron density data one month before and one month after 12 strong earthquakes that have occurred in the first 2.5 years of Swarm satellite mission lifetime in the Mediterranean region (magnitude M6.1+) or in the rest of the world (M6.7+). The search for anomalies was limited to the area centred at each earthquake epicentre and bounded by a circle that scales with magnitude according to the Dobrovolsky’s radius. We define the magnetic and electron density anomalies statistically in terms of specific thresholds with respect to the same statistical quantity along the whole residual satellite track (|geomagnetic latitude| ≤ 50°, quiet geomagnetic conditions). Once normalized by the analysed satellite tracks, the anomalies associated to all earthquakes resemble a linear dependence with earthquake magnitude, so supporting the statistical correlation with earthquakes and excluding a relationship by chance.

Research paper thumbnail of Rupture Directivity of the Strongest 2016-2017 Central Italy Earthquakes

Journal of Geophysical Research: Solid Earth

The along-strike rupture directivity of 16 of the strongest earthquakes (4.4 ≤ M w ≤ 6.5) within ... more The along-strike rupture directivity of 16 of the strongest earthquakes (4.4 ≤ M w ≤ 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.

Research paper thumbnail of 3 Seismicity and stress field in the Sannio-Matese area

In this study we discuss the available data on seismicity and focal mechanisms in the Sannio-Mate... more In this study we discuss the available data on seismicity and focal mechanisms in the Sannio-Matese area in order to obtain information on the stress field acting in the area. Background seismicity of the area is characterized by isolated events, with magnitude generally less than 2.5, on which is superimposed a swarm and seismic sequence activity of low magnitude (max magnitude 4.1). The epicentral distribution of both isolated events and seismic sequences, disclose NE-SW striking active faults that fall in between the fault segments of the large historical earthquakes which occurred in the area. The available information on the stress field deducible from the focal mechanisms of the area agrees that a general extensional stress regime is acting. Locally both NE-SW and NNW-SSE extensions are observed. The large scale stress regime deduced from the focal mechanisms of strong instrumental earthquakes which occurred in the Apennines supports the local NE-SW extension but cannot explain the normal movements related to a NW-SE extension. The local longitudinal extension observed, supported by GPS data, can be explained utilizing large scale geodynamic models.

Research paper thumbnail of Seismic activity in the transition zone between Southern and Central Apennines (Italy): Evidences of longitudinal extension inside the Ortona Roccamonfina tectonic line

Tectonophysics, 2008

We analyze the 1997–2006 seismicity of the transition zone between Southern and Central Apennines... more We analyze the 1997–2006 seismicity of the transition zone between Southern and Central Apennines, which is one of the most active seismic areas of Italy. Our aim is to add information on the seismotectonic picture of this area. Seismic activity is characterized by single events with M<3.0 and low magnitude (M<4.0) seismic sequences (1997–98 and 2005) and swarms (1999, 2000

Research paper thumbnail of Rupture Directivity of the Damaging Normal Faulting Earthquakes of the Last Twenty Years in Central Apennines

Research paper thumbnail of A seismic quiescence before the 2017 Mw 7.3 Sarpol Zahab (Iran) earthquake: Detection and analysis by improved RTL method

Physics of the Earth and Planetary Interiors, 2019

A major earthquake, with magnitude Mw 7.3, struck Sarpol Zahab (Kermanshah province, Iran) on Nov... more A major earthquake, with magnitude Mw 7.3, struck Sarpol Zahab (Kermanshah province, Iran) on November 12 2017, causing extended damage and casualties. The epicentre was located in the Northwestern part of the Zagros mountain range, an active belt originated by the Arabia-Eurasia collision. We explore seismicity preceding this earthquake, by using the Iranian Seismological Center instrumental earthquake catalog (IGTU), with the aim to identify possible anomalies in background seismicity that can be related with this and other future large events. For this purpose, we used a method for intermediate term forecasts of large earthquakes, namely the Region Time Length (RTL) algorithm, which analyzes declustered catalogs and is sensitive to quiescences that may precede major earthquakes. RTL has been progressively refined and has been applied in several regions worldwide during the last decades. To decluster the earthquake catalog we used a quite novel approach, based on the nearest-neigbour distances between events in the space-time-energy domain, a method that preserves the background seismicity while removing the clustered component. The retrospective application of RTL algorithm to the area surrounding the mainshock epicenter highlights two significant quiescences: one preceding the Sarpol Zahab Mw 7.3 earthquake, and the other occurring before a Mw 5.7 earthquake, which struck the same region

Research paper thumbnail of EPSI Project Participants

Research paper thumbnail of SAFE Project: An integrated system of earthquake physics study from ground and space observations

Angelo De Santis (1), Giorgiana De Franceschi (1), Rita Di Giovambattista (1), Loredana Perrone (... more Angelo De Santis (1), Giorgiana De Franceschi (1), Rita Di Giovambattista (1), Loredana Perrone (1), Lucilla Alfonsi (1), Gianfranco Cianchini (1), Javier F. Pavón-Carrasco (1), Claudio Cesaroni (1), Luca Spogli (1), Alessandro Piscini (1), Anna De Santis (1), Giulia D’Angelo (1), Elvira Musicò (1), Andrea Malagnini (1), Leonardo Amoruso (2), Marianna Carbone (2), Cristoforo Abbattista (2), and Daniela Drimaco (2)

Research paper thumbnail of The AMR and the Revised AMR methods as diagnostic tools for the preparatory phases of large earthquakes

Research paper thumbnail of Geosystemics and Earthquakes

Geosystemics [De Santis 2009, 2014] studies the Earth system as a whole focusing on the possible ... more Geosystemics [De Santis 2009, 2014] studies the Earth system as a whole focusing on the possible coupling among the Earth layers (the so called geo-layers), and using universal tools to integrate different methods that can be applied to multi-parameter data, often taken on different platforms. Its main objective is to understand the particular phenomenon of interest from a holistic point of view. In this paper we will deal with earthquakes, considered as a long term chain of processes involving, not only the interaction between different components of the Earth's interior, but also the coupling of the solid earth with the above neutral and ionized atmosphere, and finally culminating with the main rupture along the fault of concern [De Santis et al., 2015a]. Some case studies (particular emphasis is given to recent central Italy earthquakes) will be discussed in the frame of the geosystemic approach for better understanding the physics of the underlying complex dynamical system.

Research paper thumbnail of Possible Lithosphere-Atmosphere-Ionosphere Coupling effects prior to the 2018 Mw = 7.5 Indonesia earthquake from seismic, atmospheric and ionospheric data

Journal of Asian Earth Sciences, 2019

In this study, we analyse Lithosphere Atmosphere Ionosphere Coupling (LAIC) effects to identify s... more In this study, we analyse Lithosphere Atmosphere Ionosphere Coupling (LAIC) effects to identify some phenomena that could, possibly, be linked to the preparation phase of the M W = 7.5 earthquake occurred in Indonesia on September 28th, 2018, by investigating the eight months preceding the seismic event. First, we find a seismic acceleration that started two months before the mainshock. Then, studying some physical properties of the atmosphere (skin temperature, total column water vapor and aerosol optical thickness), we find two increases of atmospheric anomalies about 6 and 3.7 months before the mainshock, and the latter one is very promising as a candidate for seismic-related phenomena. Furthermore, we investigate ionospheric disturbances, by analysing the Swarm and, for the first time, China Seismo-Electromagnetic Satellite (CSES), magnetic and electron density data during quiet geomagnetic time. From different techniques, we find interesting anomalies concentrated around 2.7 months before the mainshock. On August 19th, 2018, Swarm and CSES showed an enhancement of the electron density during night time. We critically discuss the possibility that such phenomenon can be a possible pre-seismic-induced ionospheric effect. Finally, we performed a cumulative analysis using all detected anomalies, as a test case for a possible chain of physical phenomena that could happen before the earthquake occurrence. With this study, we support the usefulness to collect and store large Earth ground and satellite observational dataset that in the future could be useful to monitor in real time the seismic zones to anticipate earthquakes, although nowadays, there is no evidence about useful prediction capabilities.

Research paper thumbnail of Strong following earthquake forecasting by a pattern recognition approach in California 

Research paper thumbnail of Seismicity and stress field in the Sannio-Matese area

In this study we discuss the available data on seismicity and focal mechanisms in the Sannio-Mate... more In this study we discuss the available data on seismicity and focal mechanisms in the Sannio-Matese area in order to obtain information on the stress field acting in the area. Background seismicity of the area is characterized by isolated events, with magnitude generally less than 2.5, on which is superimposed a swarm and seismic sequence activity of low magnitude (max magnitude 4.1). The epicentral distribution of both isolated events and seismic sequences, disclose NE-SW striking active faults that fall in between the fault segments of the large historical earthquakes which occurred in the area. The available information on the stress field deducible from the focal mechanisms of the area agrees that a general extensional stress regime is acting. Locally both NE-SW and NNW-SSE extensions are observed. The large scale stress regime deduced from the focal mechanisms of strong instrumental earthquakes which occurred in the Apennines supports the local NE-SW extension but cannot explain the normal movements related to a NW-SE extension. The local longitudinal extension observed, supported by GPS data, can be explained utilizing large scale geodynamic models.

Research paper thumbnail of Large amplitude variations recorded by an on-fault seismological station during the L'Aquila earthquakes: Evidence for a complex fault-induced site effect

Geophysical Research Letters, 2010

Motivation: One station, FAGN, installed on a segment of the fault system that generated the Apri... more Motivation: One station, FAGN, installed on a segment of the fault system that generated the April 2009 earthquakes, shows anomalously larger ground motions compared the nearby stations.

Research paper thumbnail of Seismic and geodetic evidences of a hydrothermal source in the M d 4.0, 2017 Ischia earthquake (Italy)

Journal of Geophysical Research: Solid Earth

Research paper thumbnail of 3 Seismicity and stress field in the Sannio-Matese area

In this study we discuss the available data on seismicity and focal mechanisms in the Sannio-Mate... more In this study we discuss the available data on seismicity and focal mechanisms in the Sannio-Matese area in or-der to obtain information on the stress field acting in the area. Background seismicity of the area is character-ized by isolated events, with magnitude generally less than 2.5, on which is superimposed a swarm and seismicsequence activity of low magnitude (max magnitude 4.1). The epicentral distribution of both isolated events andseismic sequences, disclose NE-SW striking active faults that fall in between the fault segments of the large his-torical earthquakes which occurred in the area. The available information on the stress field deducible from thefocal mechanisms of the area agrees that a general extensional stress regime is acting. Locally both NE-SW andNNW-SSE extensions are observed. The large scale stress regime deduced from the focal mechanisms of stronginstrumental earthquakes which occurred in the Apennines supports the local NE-SW extension but cannot ex-plain...

Research paper thumbnail of Stress drop, apparent stress, and radiation efficiency of clustered earthquakes in the nucleation volume of the April 6, 2009, M w 6.1 L'Aquila earthquake

Journal of Geophysical Research: Solid Earth

Research paper thumbnail of Spatio-temporal variations of source parameters in the nucleation zone of the 6 April 2009, Mw 6.1 L'Aquila Earthquake

&... more <p>We present the results of Brune stress drop (∆σ) and apparent stress (τa) variability of  earthquakes located in a small zone adjacent to the hypocenter of the damaging Mw 6.1 L'Aquila earthquake. Their magnitude ranges between  2.7 and 4.1. Interevent variability of stress drop and apparent stress results in a factor of 10, well beyond the individual‐event uncertainty. Radiation efficiency ηsw = τa/∆σ varies mostly between 0.1 and 0.2, but decreases in the days immediately before and after the main shock to values as low as 0.06. This may be related to the migration of the events occurring in those days into a focal volume with higher dynamic strength. The temporal change of ηsw might be interpreted as a spatial variation due to the earthquake migration into the locked portion of the fault originating the main shock. Furthermore, no variation in stress drop and apparent stress can be observed between foreshocks and aftershocks but the smallest and largest ∆σ result in a good correlation with the largest and smallest b‐values respectively, as already documented in literature in the rupture nucleation volume of large earthquakes.</p>

Research paper thumbnail of Revised Accelerated Moment Release Under Test: Fourteen Worldwide Real Case Studies in 2014–2018 and Simulations

Pure and Applied Geophysics

Research paper thumbnail of Geosystemics View of Earthquakes

Entropy

Earthquakes are the most energetic phenomena in the lithosphere: their study and comprehension ar... more Earthquakes are the most energetic phenomena in the lithosphere: their study and comprehension are greatly worth doing because of the obvious importance for society. Geosystemics intends to study the Earth system as a whole, looking at the possible couplings among the different geo-layers, i.e., from the earth’s interior to the above atmosphere. It uses specific universal tools to integrate different methods that can be applied to multi-parameter data, often taken on different platforms (e.g., ground, marine or satellite observations). Its main objective is to understand the particular phenomenon of interest from a holistic point of view. Central is the use of entropy, together with other physical quantities that will be introduced case by case. In this paper, we will deal with earthquakes, as final part of a long-term chain of processes involving, not only the interaction between different components of the Earth’s interior but also the coupling of the solid earth with the above ne...

Research paper thumbnail of Magnetic Field and Electron Density Data Analysis from Swarm Satellites Searching for Ionospheric Effects by Great Earthquakes: 12 Case Studies from 2014 to 2016

Atmosphere

We analyse Swarm satellite magnetic field and electron density data one month before and one mont... more We analyse Swarm satellite magnetic field and electron density data one month before and one month after 12 strong earthquakes that have occurred in the first 2.5 years of Swarm satellite mission lifetime in the Mediterranean region (magnitude M6.1+) or in the rest of the world (M6.7+). The search for anomalies was limited to the area centred at each earthquake epicentre and bounded by a circle that scales with magnitude according to the Dobrovolsky’s radius. We define the magnetic and electron density anomalies statistically in terms of specific thresholds with respect to the same statistical quantity along the whole residual satellite track (|geomagnetic latitude| ≤ 50°, quiet geomagnetic conditions). Once normalized by the analysed satellite tracks, the anomalies associated to all earthquakes resemble a linear dependence with earthquake magnitude, so supporting the statistical correlation with earthquakes and excluding a relationship by chance.

Research paper thumbnail of Rupture Directivity of the Strongest 2016-2017 Central Italy Earthquakes

Journal of Geophysical Research: Solid Earth

The along-strike rupture directivity of 16 of the strongest earthquakes (4.4 ≤ M w ≤ 6.5) within ... more The along-strike rupture directivity of 16 of the strongest earthquakes (4.4 ≤ M w ≤ 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.

Research paper thumbnail of 3 Seismicity and stress field in the Sannio-Matese area

In this study we discuss the available data on seismicity and focal mechanisms in the Sannio-Mate... more In this study we discuss the available data on seismicity and focal mechanisms in the Sannio-Matese area in order to obtain information on the stress field acting in the area. Background seismicity of the area is characterized by isolated events, with magnitude generally less than 2.5, on which is superimposed a swarm and seismic sequence activity of low magnitude (max magnitude 4.1). The epicentral distribution of both isolated events and seismic sequences, disclose NE-SW striking active faults that fall in between the fault segments of the large historical earthquakes which occurred in the area. The available information on the stress field deducible from the focal mechanisms of the area agrees that a general extensional stress regime is acting. Locally both NE-SW and NNW-SSE extensions are observed. The large scale stress regime deduced from the focal mechanisms of strong instrumental earthquakes which occurred in the Apennines supports the local NE-SW extension but cannot explain the normal movements related to a NW-SE extension. The local longitudinal extension observed, supported by GPS data, can be explained utilizing large scale geodynamic models.

Research paper thumbnail of Seismic activity in the transition zone between Southern and Central Apennines (Italy): Evidences of longitudinal extension inside the Ortona Roccamonfina tectonic line

Tectonophysics, 2008

We analyze the 1997–2006 seismicity of the transition zone between Southern and Central Apennines... more We analyze the 1997–2006 seismicity of the transition zone between Southern and Central Apennines, which is one of the most active seismic areas of Italy. Our aim is to add information on the seismotectonic picture of this area. Seismic activity is characterized by single events with M<3.0 and low magnitude (M<4.0) seismic sequences (1997–98 and 2005) and swarms (1999, 2000