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Research paper thumbnail of Complexity of the rupture process during the 2009 L’Aquila, Italy, earthquake

Geophysical Journal International, 2012

In this study, we investigate the rupture history of the 2009 April 6 (M w 6.1) L'Aquila normal f... more In this study, we investigate the rupture history of the 2009 April 6 (M w 6.1) L'Aquila normal faulting earthquake by using a non-linear inversion of strong motion, GPS and DInSAR data. Both the separate and joint inversion solutions reveal a complex rupture process and a heterogeneous slip distribution. Slip is concentrated in two main asperities: a smaller shallow patch of slip located updip from the hypocentre and a second deeper and larger asperity located southeastwards along-strike direction.

Research paper thumbnail of Up-dip directivity in near-source during the 2009 L'Aquila main shock

Geophysical Journal International, 2014

In this study we have investigated the directivity associated with the initial up-dip rupture pro... more In this study we have investigated the directivity associated with the initial up-dip rupture propagation during the 2009 April 6 (M w 6.1) L'Aquila normal-faulting earthquake. The objective is the understanding of how the peculiar initial behaviour of rupture history during the main shock has affected the near-source recorded ground motions in the L'Aquila town and surrounding areas. We have modelled the observed ground velocities at the closest near-source recording sites by computing synthetic seismograms using a discrete wavenumbers and finite difference approach in the low frequency bandwidth (0.02-0.4 Hz) to avoid site effects contaminations. We use both the rupture model retrieved by inverting ground motion waveforms and continuous high sampling-rate GPS time-series as well as uniform-slip constant-rupture speed models.

Research paper thumbnail of Fast Determination of Moment Tensors and Rupture History: What Has Been Learned from the 6 April 2009 L'Aquila Earthquake Sequence

Seismological Research Letters, 2010

Research paper thumbnail of A global search inversion for earthquake kinematic rupture history: Application to the 2000 western Tottori, Japan earthquake

Journal of Geophysical Research, 2007

... regions 15 of parameter space. In the second stage (appraisal), the algorithm performs a stat... more ... regions 15 of parameter space. In the second stage (appraisal), the algorithm performs a statistical analysis 16 of the model ensemble and computes a weighted mean model and its standard deviation. This 17 technique, rather ...

Research paper thumbnail of Very high rate (10 Hz) GPS seismology for moderate-magnitude earthquakes: The case of the M w 6.3 L'Aquila (central Italy) event

Journal of Geophysical Research, 2011

Aquila destructive earthquake was successfully recorded by closely spaced 10 Hz and 1 Hz recordin... more Aquila destructive earthquake was successfully recorded by closely spaced 10 Hz and 1 Hz recording GPS receivers and strong motion accelerometers located above or close to the 50°dipping activated fault. We retrieved both static and dynamic displacements from very high rate GPS (VHRGPS) recordings by using Precise Point Positioning kinematic analysis. We compared the GPS positions' time series with the closest displacement time series obtained by doubly integrating strong motion data, first, to assess the GPS capability to detect the first seismic arrivals (P waves) and, second, to evaluate the accelerometers' capability to detect coseismic offsets up to ∼45 s after the earthquake occurrence. By comparing seismic and VHRGPS frequency contents, we inferred that GPS sampling rates greater than 2.5 Hz (i.e., 5 or 10 Hz) are required in the near field of moderate-magnitude events to provide "alias-free" solutions of coseismic dynamic displacements. Finally, we assessed the consistency of the dynamic VHRGPS results as a constraint on the kinematic rupture history of the main shock. These results suggested that the high-rate sampling GPS sites in the near field can be as useful as strong motion stations for earthquake source studies. (2011), Very high rate (10 Hz) GPS seismology for moderate-magnitude earthquakes: The case of the M w 6.3 L'Aquila (central Italy) event,

Research paper thumbnail of Ground-motion simulations within ShakeMap methodology: application to the 2008 Iwate-Miyagi Nairiku (Japan) and 1980 Irpinia (Italy) earthquakes

Geophysical Journal International, 2013

Research paper thumbnail of Complexity of the rupture process during the 2009 L’Aquila, Italy, earthquake

Geophysical Journal International, 2012

In this study, we investigate the rupture history of the 2009 April 6 (M w 6.1) L'Aquila normal f... more In this study, we investigate the rupture history of the 2009 April 6 (M w 6.1) L'Aquila normal faulting earthquake by using a non-linear inversion of strong motion, GPS and DInSAR data. Both the separate and joint inversion solutions reveal a complex rupture process and a heterogeneous slip distribution. Slip is concentrated in two main asperities: a smaller shallow patch of slip located updip from the hypocentre and a second deeper and larger asperity located southeastwards along-strike direction.

Research paper thumbnail of Variability of Kinematic Source Parameters and Its Implication on the Choice of the Design Scenario

Bulletin of the Seismological Society of America, 2010

... Giovanna Cultrera, Antonella Cirella, Elena Spagnuolo, André Herrero, and Elisa Tinti ... Ist... more ... Giovanna Cultrera, Antonella Cirella, Elena Spagnuolo, André Herrero, and Elisa Tinti ... Istituto Nazionale di Geofisica e Vulcanologia, Via Bassini 15, 20133, Milano, Italy. ... The source model of Irpinia mainshock, inferred from the inversion of strong-motion data (Cocco and Pacor ...

Research paper thumbnail of The rupture history of the 2009 L'Aquila earthquake by non-linear joint inversion of strong motion and GPS data

ABSTRACT The 2009 L’Aquila earthquake (Mw 6.3) occurred in the Central Apennines (Italy) on April... more ABSTRACT The 2009 L’Aquila earthquake (Mw 6.3) occurred in the Central Apennines (Italy) on April 6th at the 01:32 UTC and caused nearly 300 fatalities and heavy damages in the L’Aquila town and in several villages nearby. The main shock ruptured a normal fault striking along the Apennine axis and dipping at nearly 50° to the SW. Most of the aftershocks are also associated with normal faulting, which is consistent with the present-day tectonic setting of this sector of the Apennines. The identification of the fault geometry of the L’Aquila main shock relies on the aftershock pattern, the SAR interferometric data, the GPS displacements as well as the induced surface breakages. The earthquake allowed for the collection of an excellent data set for normal faulting events. In this study, we have imaged the rupture history of the L’Aquila earthquake using a nonlinear joint inversion of strong motion and GPS data. Our results show that slip distribution on the fault is quite heterogeneous and characterized by a small shallow slip patch located up-dip the hypocenter and a large and deeper patch located southeastward. The rupture velocity is larger in the up-dip than in the along-strike direction. This difference can be partially accounted by the local crustal structure, which is characterized by a high velocity layer above the hypocenter (9.46 km) and a lower velocity below. The latter velocity seems to have affected the along strike propagation since the largest slip patch is located at depths between 9 and 14 km. The imaged slip distribution correlates well with the on-fault aftershock pattern as well as with mapped surface breakages. The rupture history is also consistent with the large PGA values recorded at L’Aquila that is located right above the hypocenter.

Research paper thumbnail of Rupture history of the 2009 L'Aquila (Italy) earthquake from non-linear joint inversion of strong motion and GPS data

Research paper thumbnail of Complexity of the rupture process during the 2009 L’Aquila, Italy, earthquake

Geophysical Journal International, 2012

In this study, we investigate the rupture history of the 2009 April 6 (M w 6.1) L'Aquila normal f... more In this study, we investigate the rupture history of the 2009 April 6 (M w 6.1) L'Aquila normal faulting earthquake by using a non-linear inversion of strong motion, GPS and DInSAR data. Both the separate and joint inversion solutions reveal a complex rupture process and a heterogeneous slip distribution. Slip is concentrated in two main asperities: a smaller shallow patch of slip located updip from the hypocentre and a second deeper and larger asperity located southeastwards along-strike direction.

Research paper thumbnail of Up-dip directivity in near-source during the 2009 L'Aquila main shock

Geophysical Journal International, 2014

In this study we have investigated the directivity associated with the initial up-dip rupture pro... more In this study we have investigated the directivity associated with the initial up-dip rupture propagation during the 2009 April 6 (M w 6.1) L'Aquila normal-faulting earthquake. The objective is the understanding of how the peculiar initial behaviour of rupture history during the main shock has affected the near-source recorded ground motions in the L'Aquila town and surrounding areas. We have modelled the observed ground velocities at the closest near-source recording sites by computing synthetic seismograms using a discrete wavenumbers and finite difference approach in the low frequency bandwidth (0.02-0.4 Hz) to avoid site effects contaminations. We use both the rupture model retrieved by inverting ground motion waveforms and continuous high sampling-rate GPS time-series as well as uniform-slip constant-rupture speed models.

Research paper thumbnail of Fast Determination of Moment Tensors and Rupture History: What Has Been Learned from the 6 April 2009 L'Aquila Earthquake Sequence

Seismological Research Letters, 2010

Research paper thumbnail of A global search inversion for earthquake kinematic rupture history: Application to the 2000 western Tottori, Japan earthquake

Journal of Geophysical Research, 2007

... regions 15 of parameter space. In the second stage (appraisal), the algorithm performs a stat... more ... regions 15 of parameter space. In the second stage (appraisal), the algorithm performs a statistical analysis 16 of the model ensemble and computes a weighted mean model and its standard deviation. This 17 technique, rather ...

Research paper thumbnail of Very high rate (10 Hz) GPS seismology for moderate-magnitude earthquakes: The case of the M w 6.3 L'Aquila (central Italy) event

Journal of Geophysical Research, 2011

Aquila destructive earthquake was successfully recorded by closely spaced 10 Hz and 1 Hz recordin... more Aquila destructive earthquake was successfully recorded by closely spaced 10 Hz and 1 Hz recording GPS receivers and strong motion accelerometers located above or close to the 50°dipping activated fault. We retrieved both static and dynamic displacements from very high rate GPS (VHRGPS) recordings by using Precise Point Positioning kinematic analysis. We compared the GPS positions' time series with the closest displacement time series obtained by doubly integrating strong motion data, first, to assess the GPS capability to detect the first seismic arrivals (P waves) and, second, to evaluate the accelerometers' capability to detect coseismic offsets up to ∼45 s after the earthquake occurrence. By comparing seismic and VHRGPS frequency contents, we inferred that GPS sampling rates greater than 2.5 Hz (i.e., 5 or 10 Hz) are required in the near field of moderate-magnitude events to provide "alias-free" solutions of coseismic dynamic displacements. Finally, we assessed the consistency of the dynamic VHRGPS results as a constraint on the kinematic rupture history of the main shock. These results suggested that the high-rate sampling GPS sites in the near field can be as useful as strong motion stations for earthquake source studies. (2011), Very high rate (10 Hz) GPS seismology for moderate-magnitude earthquakes: The case of the M w 6.3 L'Aquila (central Italy) event,

Research paper thumbnail of Ground-motion simulations within ShakeMap methodology: application to the 2008 Iwate-Miyagi Nairiku (Japan) and 1980 Irpinia (Italy) earthquakes

Geophysical Journal International, 2013

Research paper thumbnail of Complexity of the rupture process during the 2009 L’Aquila, Italy, earthquake

Geophysical Journal International, 2012

In this study, we investigate the rupture history of the 2009 April 6 (M w 6.1) L'Aquila normal f... more In this study, we investigate the rupture history of the 2009 April 6 (M w 6.1) L'Aquila normal faulting earthquake by using a non-linear inversion of strong motion, GPS and DInSAR data. Both the separate and joint inversion solutions reveal a complex rupture process and a heterogeneous slip distribution. Slip is concentrated in two main asperities: a smaller shallow patch of slip located updip from the hypocentre and a second deeper and larger asperity located southeastwards along-strike direction.

Research paper thumbnail of Variability of Kinematic Source Parameters and Its Implication on the Choice of the Design Scenario

Bulletin of the Seismological Society of America, 2010

... Giovanna Cultrera, Antonella Cirella, Elena Spagnuolo, André Herrero, and Elisa Tinti ... Ist... more ... Giovanna Cultrera, Antonella Cirella, Elena Spagnuolo, André Herrero, and Elisa Tinti ... Istituto Nazionale di Geofisica e Vulcanologia, Via Bassini 15, 20133, Milano, Italy. ... The source model of Irpinia mainshock, inferred from the inversion of strong-motion data (Cocco and Pacor ...

Research paper thumbnail of The rupture history of the 2009 L'Aquila earthquake by non-linear joint inversion of strong motion and GPS data

ABSTRACT The 2009 L’Aquila earthquake (Mw 6.3) occurred in the Central Apennines (Italy) on April... more ABSTRACT The 2009 L’Aquila earthquake (Mw 6.3) occurred in the Central Apennines (Italy) on April 6th at the 01:32 UTC and caused nearly 300 fatalities and heavy damages in the L’Aquila town and in several villages nearby. The main shock ruptured a normal fault striking along the Apennine axis and dipping at nearly 50° to the SW. Most of the aftershocks are also associated with normal faulting, which is consistent with the present-day tectonic setting of this sector of the Apennines. The identification of the fault geometry of the L’Aquila main shock relies on the aftershock pattern, the SAR interferometric data, the GPS displacements as well as the induced surface breakages. The earthquake allowed for the collection of an excellent data set for normal faulting events. In this study, we have imaged the rupture history of the L’Aquila earthquake using a nonlinear joint inversion of strong motion and GPS data. Our results show that slip distribution on the fault is quite heterogeneous and characterized by a small shallow slip patch located up-dip the hypocenter and a large and deeper patch located southeastward. The rupture velocity is larger in the up-dip than in the along-strike direction. This difference can be partially accounted by the local crustal structure, which is characterized by a high velocity layer above the hypocenter (9.46 km) and a lower velocity below. The latter velocity seems to have affected the along strike propagation since the largest slip patch is located at depths between 9 and 14 km. The imaged slip distribution correlates well with the on-fault aftershock pattern as well as with mapped surface breakages. The rupture history is also consistent with the large PGA values recorded at L’Aquila that is located right above the hypocenter.

Research paper thumbnail of Rupture history of the 2009 L'Aquila (Italy) earthquake from non-linear joint inversion of strong motion and GPS data