Emanuele Casarotti

National Institute of Geophysics and Volcanology | INGV

We present forward and adjoint spectral-element simulations of coupled acoustic and (an)elastic seismic wave propagation on fully unstructured hexahedral meshes. Simulations benefit from recent advances in hexahedral meshing, load balancing and software optimization. Meshing may be accomplished using a mesh generation tool kit such as CUBIT, and lo...

Unstructured hexahedral mesh generation is a critical part of the modeling process in the Spectral-Element Method (SEM). We present some examples of seismic wave propagation in complex geological models, automatically meshed on a parallel machine based upon CUBIT (Sandia Laboratory), an advanced 3D unstructured hexahedral mesh generator that offers...

Understanding the dynamics of microearthquakes is a timely challenge with the potential to address current paradoxes in earthquake mechanics, and to better understand earthquake ruptures induced by fluid injection. We perform fully 3D dynamic rupture simulations caused by fluid injection on a target fault for FEAR experiments generating Mw ≤ 1 eart...

79 Giornata ONT Miscellanea INGV

The EU Center of Excellence for Exascale in Solid Earth (ChEESE) develops exascale transition capabilities in the domain of SolidEarth, an area of geophysics rich in computational challenges embracing different approaches to exascale (capability, capacity and urgent computing). The first implementation phase of the project (ChEESE-1P; 2018-2022) ad...

Communicating scientific information about earthquakes is an important and delicate issue in countries like Italy, where seismic risk is high. Furthermore, continuous and scientifically sound communication is needed, especially in recent times when social media have amplified the risk of being biased by misinformation, fake news and conspiracy theo...

The evolution and state of geological structure at Earth’s surface is best understood with an accurate characterization of the subsurface. Here we present seismic tomographic images of the Italian lithosphere based on ground motion recordings and characterized by compressional and shear wavespeed structure at remarkable resolution, corresponding to...

The 2016 Central Italy earthquake sequence is characterized by remarkable rupture complexity, including highly heterogeneous slip across multiple faults in an extensional tectonic regime. The dense coverage and high quality of geodetic and seismic data allow us to image intriguing details of the rupture kinematics of the largest earthquake of the s...

The DARE platform has been designed to help research developers deliver user-facing applications and solutions over diverse underlying e-infrastructures, data and computational contexts. The platform is Cloud-ready, and relies on the exposure of APIs, which are suitable for raising the abstraction level and hiding complexity. At its core, the platf...

In recent years the potential to improve resolution of seismic imaging by full waveform inversion has been demonstrated on a range of scales from local to global, and powerful procedures are increasingly developed by researchers to tackle these issues. The VERCE portal has been specifically designed to allow scientists to exploit widespread, perfor...

We present here the first application of the fast reacting framework for 3D simulations of seismic wave propagation generated by earthquakes in the Italian region with magnitude Mw ≥ 5. The driven motivation is to offer a visualization of the natural phenomenon to the general public but also to provide preliminary modeling to expert and civil prote...

The magnitude Mw 6.0 earthquake of 24th August 2016 caused severe damages and nearly 300 fatalities in the central Italy region. Initial reports revealed an asymmetrical distribution of damage and coseismic effects, suggesting a major role of heterogeneities, both in the rupture history and in the geological structure of the region. Near realtime a...

The main goal of this paper is analysing how user’s location, relative to the epicenter of an earthquake, affects the different tweeting strategies adopted. For this purpose, we analyze a dataset of tweets that were generated around the 2012 Emilia earthquakes and that are geolocalized in Italy. In our analysis, we rely on existing literature on so...

Geological and seismological observations have been used to parameterize 2-D numerical elastic models to simulate the interseismic deformation of a complex extensional fault system located in the Northern Apennines (Italy). The geological system is dominated by the presence of the Alto Tiberina fault (ATF), a large (60 km along strike) low-angle no...

Geological and seismological observations have been used to parameterize 2D numerical models to simulate the interseismic deformation of a complex extensional fault system located in the Northern Apennines (Italy). The geological system is dominated by the presence of the Altotiberina fault (ATF), a large (60 km along strike) low-angle normal fault...

The VERCE project has pioneered an e-Infrastructure to support researchers using established simulation codes on high-performance computers in conjunction with multiple sources of observational data. This is accessed and organised via the VERCE science gateway that makes it convenient for seismologists to use these resources from any location via t...

On 6 April 2009, an M w 6.2 earthquake struck beneath the city of L’Aquila, central Italy. The shock created significant damage and caused more than 300 deaths in the city and environs. The event followed a seismic sequence that started at the beginning of the year, with its largest shock of M w 4.2 occurring on 30 March. The 6 April earthquake bec...

We adopt a spectral-element method (SEM) to perform numerical simulations of the complex wavefield generated by the 6 April 2009 Mw 6.3 L’Aquila earthquake in central Italy. The mainshock is represented by a finite-fault solution obtained by inverting strong-motion and Global Positioning System data, testing both 1D and 3D wavespeed models for cent...

Advanced application environments for seismic analysis help geoscientists to execute complex simulations to predict the behaviour of a geophysical system and potential surface observations. At the same time data collected from seismic stations must be processed comparing recorded signals with predictions. The EU-funded project VERCE ( http://verce....

[1] Ambient-noise seismology is of great relevance to high-resolution crustal imaging, thanks to the unprecedented dense data coverage it affords in regions of little seismicity. Under the assumption of uniformly distributed noise sources, it has been used to extract the Green's function between two receivers. We determine the imprint of this assum...

Recently, advances in computational seismology have culminated in the development of a range of scientific codes enabling the calculation of highly accurate 3D wave and rupture propagation in complex 3D media at unprecedented scales and level of detail. Fortunately, the computational hardware has grown at rates at least as vigorous, to match up to...

The overall picture of Mount Etna deformation emerging since a couple of decades of geodetic surveys shows effects of magma accumulation, characterized by inflation/deflation cycle, accompanied by a sliding instability of the southeast flank, whose manifestation is an increase in the horizontal deformation away from the volcano summit. This is a ve...

This article outlines a new approach to rapidly estimate the damage to tall buildings immediately following a large earthquake. The preevent groundwork involves the creation of a database of structural responses to a suite of idealized ground-motion waveforms. The postevent action involves (1) rapid generation of an earthquake source model, (2) nea...

During a seismic sequence, it is extremely important that the population shaken by the earthquakes has continuous and timely information about the ongoing seismic activity. For this reason, a few days after the beginning of the Po Plain sequence, we opened a new informative channel, namely a blog (http://ingvterremoti.wordpress.com), through which...

A devastating earthquake was predicted to hit Rome on May 11, 2011. This prediction was never officially released, but it grew on the internet and was amplified by the media. It was erroneously ascribed to Raffaele Bendandi, an Italian self-taught natural scientist who studied planetary motions and related them to earthquakes. Indeed, around May 11...

In February 2010, we launched an experimental scientific video channel on YouTube (http://www.youtube.com/ingvterremoti), to improve our communication strategy for earthquake risk and preparedness. The main goals of this initiative were to inform people of the ongoing seismic activity in Italy and around the World, to communicate the results of sci...

We adopt a finite element method to investigate the effect of 3D variation of material properties in the subduction zone using the coseismic and postseismic deformation of the 2005 Mw 8.7 Nias-Simeulue, Sumatra earthquake. In this study, we construct a simple subduction model using the mesh generation software, Cubit, developed by Sandia National L...

Our aim is to iteratively improve an initial 3D tomographic model of the lithosphere in central Italy. The spectral-element method (SEM) is adopted to perform accurate numerical simulations of the wavefield generated by foreshocks and aftershocks of the 2009 L'Aquila (Italy) earthquake, and by some additional events. The inversion is performed usin...

In 2010, Internet rumors started to circulate about a devastating earthquake allegedly forecast in Rome, on May 11, 2011, by Raffaele Bendandi, an Italian self-Taught natural scientist (Faenza, 1893-1979). As the date approached, Roman residents, tourists and commuters started pelting INGV with anxious inquiries. As May approached, the attention of...

Using finite element models (FEMs), we examine the sensitivity of surface displacements to the location of fault slip, topography, and three-dimensional variations in elastic moduli in the context of a 2-D infinite thrust fault. We then evaluate the impact of these factors and fault geometry on surface displacements and estimates of the distributio...

Accurately modeling seismic wave propagation is a challenging goal, especially if 3D complex structural volumes and realistic finite sources are considered. However, a detailed simulation of the seismic wavefield is fundamental in view of predicting large earthquake ground motion and preliminary for inverting structure and source models. We present...

The L'Aquila earthquake (Mw 6.3) occurred on April 6th at 01:32 UTC in the Central Appennines at a depth of about 9 km and was felt all over the central Italy. The main shock was preceded by a long seismic sequence started several months before and was followed by thousands of aftershocks, some of them with Mw>4. In this work we present a 3D Finite...

Mount Etna geodetic and satellite monitoring systems have been recording surface deformation characterized by an instability of the E flank of the volcano for about 20 years. The seaward sliding of the E flank is observed either during summit and flank eruptions but also during quiescent recharging phases. Many investigations have not yet been able...

On April 6 2009, a Mw 6.3 earthquake shook Central Italy and caused heavy damage and deaths in the city of L'Aquila. The region is characterized by strong geological heterogeneities and prominent topographic features, leading to remarkable site effects. We present a comparison of the seismograms recorded by the Italian National Seismic Network and...

The L'Aquila earthquake (Mw 6.3) occurred on April 6th at 01:32 UTC in the Central Appennines at a depth of about 9 km and was felt all over Central Italy. The main shock was preceded by a long seismic sequence started several months before and was followed by thousands of aftershocks, some of them with Mw>4. We built up a high resolution three-dim...

The interpretation of deformation recorded at Mount Etna and Stromboli during quiescent or paroxystic phases requires a new class of numerical models to deal with complexities such as anelastic rheologies or slip on pre-existing discontinuities. We present scripting procedures aimed to create high quality finite element discretizations of Mount Etn...

The Spectral Element Method (SEM) has been successfully applied to simulate ground motion in Southern California and the Los Angeles Basin for period up to 2 sec. Nowadays, simulations at shorter period are computationally feasible, but they require both a realistic geological model and a detailed unstructured hexahedral mesh. Aiming to include the...

The development of monitoring networks both at Mount Etna and Stromboli provided a fairly detailed database of geodetic and seismological observations during the unrest and eruptive/explosive phases of the last few years. These data reveal a tight interaction between magmatic and seismic activities. Their interpretation requires a new generation of...

Wave propagation phenomena can nowadays be studied thanks to many powerful numerical techniques. Spurred by the computational power made available by parallel computers, geoscientists and engineers can now accurately compute synthetic seismograms in realistic 3D Earth models. In this field, the Spectral Element Method (SEM) has convincingly demonst...

Unstructured hexahedral mesh generation is a critical part of the modeling process in the Spectral-Element Method (SEM). We present some examples of seismic wave propagation in complex geological models, automatically meshed on a parallel machine based upon CUBIT (Sandia Laboratory, cubit.sandia.gov), an advanced 3D unstructured hexahedral mesh gen...

The giant Sumatra-Andaman earthquake of December 26, 2004 caused permanent deformations effects in a region of previously never observed extension. The GPS data from the worldwide network of permanent IGS sites show significant coseismic displacements in an area exceeding 107 km2, reaching most of South-East Asia, besides Indonesia and India. We ha...

The giant Sumatra-Andaman earthquake of December 26 2004 caused permanent deformations effects in a region of previously never observed extension. The GPS data from the world wide network of permanent IGS sites show significant coseismic displacements in an area exceeding 107 km^2. The effects of the permanent residual deformation field could be de...

The great Sumatrian earthquake (Dic. 2004) is the third earthquake ever recorded in term of energy released, and it occurred in a strongly active volcanic region. The strong stress perturbations due to this event give the opportunity to constrain our knowledge about the effects of those perturbations on the surrounding volcanic systems. Here, we pr...

In order to improve our knowledge about fault interaction at long distances, we developed a synthetic fault system based on a spherical, viscoelastic, self-gravitating earth model. Though seismicity in our simulation is controlled mainly by tectonic loading, our results highlight the significant role played by stress transfer in assessing the spati...

We propose a formal procedure to validate the hypothesis of a causal relationship between great tectonic earthquakes and volcanic eruptions through a forward statistical test. This approach allows such a hypothesis to be evaluated in an objective way, ruling out any possible unconscious overfitting of the past data. The procedure consists of two st...

1] Using a spherical model of postseismic deformation, for the first time we have computed the global contribution of large earthquakes to the relative sealevel variations in the twentieth century. We have found that great earthquakes have the overall tendency to produce a sealevel rise, and that they affect the measurements taken at those tide-gau...

By means of a model of global postseismic deformation we have computed the cumulative residual vertical displacement, the geoid heigth changes and the relative sea level variations due to all the M>=7 earthquakes of the last century. Our aim is to ascertain if earthquakes could play a role in the assessment of the trend of sea level rise observed b...

By means of a spherical model of global postseismic deformation we perform an analysis of the postseismic stress diffusion process associated with the main seismic events which occurred in Chile and South Peru in the last century. Our aim is to ascertain if the viscoelastic relaxation of the mantle and asthenosphere following the earthquakes, super...

We investigated the plausibility of remote fault triggering on a global scale as a result of postseismic stress transfer by large earthquakes. Previous studies have shown that the postseismic stress field generated by eight of the largest events that have occurred in the Pacific area promoted the rupture of 53.6% of all the M≥5 events recorded in t...

One of the most recent novelties in volcanology is the finding of a statistically significant influence of remote strong earthquakes on the largest explosive eruptions of the last century. Here, we model such interaction in terms of the coseismic and postseismic stress diffusion. The stress variation consists of the elastic response of the lithosph...

By means of a spherical model of global postseismic deformation we perform an analysis of the postseismic stress diffusion associated with the main events occurred in Chile and South Peru in the last century. Our aim is to ascertain if the viscoelastic relaxation of mantle and asthenosphere following the earthquakes, superimposing to the main mecha...

Until few years ago, the volcanoes were usually considered systems without significant interactions with the surrounding regions. This paradigm was recently put in doubt by the finding of some possible correlation between regional earthquakes and volcanic eruptions. One of the main goals of this work is to provide phenomenological and theoretical e...

By means of a new theoretical model of global postseismic deformation we compute the time-depending postseismic stress field associated with eight of the greatest events of the century on an area extending for almost half of the Earth’s surface. We evaluate the stress transferred by these big earthquakes to all the seismogenic structures of the Pac...

The Andaman Islands -Sumatra earthquake (M w = 9.3, Dec. 2004) and the subse-quent Sumatra earthquake (M w = 8.7, Mar. 2005) represent one of most energetic sequence of earthquakes ever recorded. Since both events occurred in a strongly active volcanic region, their exceptionally strong stress perturbation gives the op-portunity to understand the e...

While fault interaction at local or regional scale is supported by wide phenomenological evidence and is considered an important feature in seismic hazard assessment, the possibility of interaction between seismogenic structures at longer distances is still a matter of debate. We present new results about the plausibility of remote fault triggering...