Gianluca Norini | Consiglio Nazionale delle Ricerche (CNR) (original) (raw)

Papers by Gianluca Norini

Remote Sensing, 2015

We study land subsidence processes and the associated ground fissuring, affecting an active grabe... more We study land subsidence processes and the associated ground fissuring, affecting an active graben filled by thick unconsolidated deposits by means of InSAR techniques and fieldwork. On 21 September 2012, Ciudad Guzmán (Jalisco, Mexico) was struck by ground fissures of about 1.5 km of length, causing the deformation of the roads and the propagation of fissures in adjacent buildings. The field survey showed that fissures alignment is coincident with the escarpments produced on 19 September 1985, when a strong earthquake with magnitude 8.1 struck central Mexico. In order to detect and map the spatio-temporal features of the processes that led to the 2012 ground fissures, we applied InSAR multitemporal techniques to process ENVISAT-ASAR and RADARSAT-2 satellite SAR images acquired between 2003 and 2012. We detect up to 20 mm/year of subsidence of the northwestern part of Ciudad Guzmán. These incremental movements are consistent with the OPEN ACCESS Remote Sens. 2015, 7 8611 ground fissures observed in 2012. Based on interferometric results, field data and 2D numerical model, we suggest that ground deformations and fissuring are due to the presence of areal subsidence correlated with variable sediment thickness and differential compaction, partly driven by the exploitation of the aquifers and controlled by the distribution and position of buried faults.

Revista Mexicana De Ciencias Geologicas, 2014

On November 16th 2006 a sector collapse affected the unstable eastern flank of the South-East Cra... more On November 16th 2006 a sector collapse affected the unstable eastern flank of the South-East Crater (SEC) on Mount Etna Volcano. The SEC is located on the Etna volcano summit and is an active steep cone formed by alternated scoria deposits and lava flows traversed by numerous fractures. The collapse occurred during an eruptive event and was probably triggered by

The present study concerns the numerical modeling of debris avalanches on the Nevado de Toluca Vo... more The present study concerns the numerical modeling of debris avalanches on the Nevado de Toluca Volcano (Mexico) using TITAN2D simulation software, and its application to create hazard maps. Nevado de Toluca is an andesitic to dacitic stratovolcano of Late Pliocene-Holocene age, located in central México near to the cities of Toluca and México City; its past activity has endangered an

Ortuño Candela M., Zúñiga F. R., Corominas O., Perea H., Ramírez-Herrera M.T., Štepancíková P., V... more Ortuño Candela M., Zúñiga F. R., Corominas O., Perea H., Ramírez-Herrera M.T., Štepancíková P., Villamor P., Aguirre G., Norini G.

A Mw 7.2 earthquake devastated Bohol Island in the Central Philippines region on 15 October 2013 ... more A Mw 7.2 earthquake devastated Bohol Island in the Central Philippines region on 15 October 2013 at 8:12 am. The temblor was associated with severe ground rupture, intense ground shaking and other earthquake hazards. Along with numerous landslides and sinkholes that formed during the event, the Bohol earthquake caused 222 deaths and massive destruction to infrastructure amounting to 1.64 million Philippine Pesos (US$38.21 million). The source of the main shock is from an unmapped reverse fault with slight strike-slip component. Ground rupture of the Bohol event is best exposed in Barangay (village) Anonang, Municipality of Inabanga where a fault scarp 3-m high, with mean principal orientation of N51°E is observed. Thousands of inland and offshore aftershocks were recorded, which plots on a general N55°E trend, defining a plane about 100 km long. Using a 1-m resolution digital terrain model (DTM) derived from a Light Detection and Ranging (LiDAR) airborne survey after the earthquake, lineaments were identified and validated through field mapping to define the extent of􀀃 the inland portion of the earthquake source. Other lineaments within the northern portion of Bohol Island were identified using the Lidar DTM to map out other possible structures in the region that may have been responsible for significantly large aftershocks with strike-slip movement as defined by focal mechanism solutions. Pre-event, 5-m resolution IfSAR DTMs mapped in 2012, were also used to determine changes in morphology after the 2013 temblor, including the identification of older fault scarps in Inabanga, where the newly-formed fault scarp is now seen. Results of this work can be used as reference for future studies to understand the tectonics of Bohol Island and the fatal 15 October 2013 earthquake to mitigate the impacts of future earthquake hazards in the area.

The interest in the role of magma in splitting plates at divergent plate boundaries through discr... more The interest in the role of magma in splitting plates at divergent plate boundaries through discrete rifting episodes has been re-invigorated. However, despite the renewed enthusiasm for this topic, the precise mechanism by which the magma affects the geometry, the kinematics, and the temporal evolution of a rift is still poorly understood.

Geophysical Monograph Series, 2000

... Monaco, C, P. Tapponnier, L. Tortorici, and PY Gillot, Late Qua-ternary slip rates on the Aci... more ... Monaco, C, P. Tapponnier, L. Tortorici, and PY Gillot, Late Qua-ternary slip rates on the Acireale-Piedimonte normal faults and tec ... it) Gianluca Norini, Dipartimento di Scienze della Terra, Università degli Studi di Milano, Via Mangiagalli 34, 20133 Milano, Italy, (e-mail: Gianluca. ...

Engineering Geology for Society and Territory - Volume 5, 2014

ABSTRACT On September 21st, 2012 Ciudad Guzmán (Jalisco - Mexico) was struck by an intense linear... more ABSTRACT On September 21st, 2012 Ciudad Guzmán (Jalisco - Mexico) was struck by an intense linear ground fracturation, causing deformations of roads and serious damages to some houses. In order to highlight any precursor deformation pattern in the area we applied InSAR multi-temporal analysis to process a dataset of ENVISAT satellite SAR images, acquired in 2003-2010 time span. We detected a subsidence area in the north-western part of Ciudad Guzmán up to -20 mm/y in the considered time interval. The eastern boundary of this area is coincident with the September 2012 alignment of fractures. The explanation of subsidence and surface effects, based on the interferometric results, ground data and geological observations, is probably to be found in the combination of two mechanisms such as overexploitation of the aquifers and tectonic creeping. In summary, the deformation pattern highlights a natural subsidence enforced by anthropogenic causes with the control of buried faults.

Tectonophysics, 2013

ABSTRACT The structural evolution of the Puna Plateau is characterized by the activity of both or... more ABSTRACT The structural evolution of the Puna Plateau is characterized by the activity of both orogen-parallel and orogen-oblique faults. Understanding the possible relationship between these two structural styles, their geodynamic implications and the influence on the migration of magmas is important to get insights into the tectonic and magmatic evolution of the Central Andes. In this study, we present a structural analysis of the orogen-oblique Calama-Olacapato-El Toro fault system and the surrounding orogen-parallel thrust faults in the central-eastern Puna Plateau. Morphostructural analysis and field mapping reveal the geometry, kinematics and dynamics of the tectonic features in the studied area. We propose a three-dimensional geometrical reconstruction of the main fault planes showing their attitude and intersections at depth. The study indicates that the crust underwent simultaneous deformation along both the vertical transcurrent Calama-Olacapato-El Toro fault system and the low-angle thrust faults, and that the back-arc portion of the Calama-Olacapato-El Toro fault system developed as a transfer zone among the main N-striking thrusts. Our model considers that both orogen-parallel and orogen-oblique fault systems should be regarded as parts of the same tectonic system, accommodating crustal shortening of a thickened crust. The study suggests that the tectonic control on the magma and fluid circulation in the crust is mainly related to the geometry of the fault planes and the orientation of the stress field, with a previously unrecognized important role played by the orogen-parallel thrust faults on the emplacement of the stratovolcanoes.

Journal of Volcanology and Geothermal Research, 2013

ABSTRACT Volcanic edifices are often unable to support their own load, triggering the instability... more ABSTRACT Volcanic edifices are often unable to support their own load, triggering the instability of their flanks. Many analogue models have been aimed, especially in the last decade, at understanding the processes leading to volcano flank instability; general behaviors were defined and the experimental results were compared to na-ture. However, available data at well-studied unstable volcanoes may allow a deeper understanding of the specific processes leading to instability, providing insights also at the local scale. Etna (Italy) constitutes a suitable example for such a possibility, because of its well-monitored flank instability, for which different triggering factors have been proposed in the last two decades. Among these factors, recent InSAR data high-light the role played by magmatic intrusions and a weak basement, under a differential unbuttressing at the volcano base. This study considers original and recently published experimental data to test these factors possibly responsible for flank instability, with the final aim to better understand and summarize the condi-tions leading to flank instability at Etna. In particular, we simulate the following processes: a) the long-term activity of a lithospheric boundary, as the Malta Escarpment, separating the Ionian oceanic lithosphere from the continental Sicilian lithosphere, below the most unstable east flank of the volcano; b) spreading due to a weak basement, with different boundary conditions; c) the pressurization of a magmatic reservoir, as that active during the 1994–2001 inflation period; d) dike emplacement, as observed during the major 2001 and 2002–2003 eruptions. The experimental results suggest that: 1) the long-term activity of a litho-spheric tectonic boundary may create a topographic slope which provides a differential buttressing at the volcano base, a preparing factor to drive longer-term (>10 5 years) instability on the east flank of the volcano; 2) volcano spreading (b 10 4 years) has limited effect on flank instability at Etna; 3) magmatic intrusions (b 10 1 years), both in the form of Mogi-like sources or dikes, provide the most important conditions to trigger flank instability on the shorter-term.

Journal of Geophysical Research, 2011

1] Mount Etna is characterized by significant flank instability, whose triggering factors are sti... more 1] Mount Etna is characterized by significant flank instability, whose triggering factors are still a matter of debate. We use analog models to investigate the role of different factors. In the models, a cone and base of granular material simulate the volcanic edifice and its basement. The asymmetric geometry of the basement simulates the topographic gradient around the volcano. Injections of silicone (sets A and B) and low-viscosity vegetable oil (set C) simulate the pressurization of plutonic complex, deep reservoirs, and the emplacement of dikes, respectively. Other experiments (set D) reproduce regional extensional tectonics in the last 10 5 years, within layers with different cohesion simulating strength differences in the basement. Laser scanner and control points allow the tracking of surface deformation with submillimeter precision. The asymmetric topography enhances flank instability on the side with the weakest confinement (i.e., seaside), providing the preparing factor for instability. In sets A and B, any type of pressurized reservoir enhances, up to 10 times, the amount of flank instability toward the seaside with respect to the other flanks of the volcano. In set C, dike emplacement enhances seaside flank instability up to 8 times. Regional tectonics and crustal layering in set D enhance flank instability up to 2 and 1.3 times, respectively. Considering the duration and frequency of the simulated processes in nature, we propose a semiquantitative evaluation and hierarchy of the factors controlling flank instability at Etna. Magmatic activity (point-like source inflation and dike emplacement) provides the most important triggering factor. Extensional tectonics, in the last 10 5 years, and crustal layering are more than 10 times less effective. This study shows the importance of differential buttressing at the volcano base for flank instability. This condition is an important indication to expect asymmetric activity in any volcano (flank eruptions and deformation).

EGU General Assembly 2010, held 2-7 …, 2010

Mount Etna, Italy, is characterized by the instability of its East and South flanks. Factors gove... more Mount Etna, Italy, is characterized by the instability of its East and South flanks. Factors governing this flank instability are still matter of debate. We investigate the role of different possible factors on flank instability, using analogue models. The apparatus consists of a cone and base ...

We present the results of analogue modelling designed to quantitatively investigate propagation o... more We present the results of analogue modelling designed to quantitatively investigate propagation of dikes in the upper crust and the resulting surface deformation. A range of scaled analogue materials and physical conditions of the models was tested, and pros and cons of every experimental setup were carefully evaluated to provide an enhanced methodological basis for simulation of dikes emplacement in

The Colima Volcano is currently the most active Mexican volcano. After the 1913 plinian activity ... more The Colima Volcano is currently the most active Mexican volcano. After the 1913 plinian activity the volcano presented several eruptive phases that lasted few years, but since 1991 its activity became more persistent with vulcanian eruptions, lava and dome extrusions. During the last 15 years the volcano suffered several eruptive episodes as in 1991, 1994, 1998-1999, 2001-2003, 2004 and 2005 with the emplacement of pyroclastic flows. During rain seasons lahars are frequent affecting several infrastructures such as ...

AGU Fall Meeting Abstracts, Dec 1, 2009

The Colima Volcano is currently the most active Mexican volcano. After the 1913 plinian activity,... more The Colima Volcano is currently the most active Mexican volcano. After the 1913 plinian activity, the volcano presented scattered eruptive phases that lasted few years each, but since 1991 its activity became more persistent, with vulcanian eruptions, and extrusion of lava flows and domes. During the last 15 years the volcano suffered several eruptive episodes, as in 1991, 1994, 1998-1999, 2001-2003, 2004 and 2005, with the emplacement of pyroclastic flows. During rain seasons lahars are frequently affecting several ...

We present a new tool for the textural study of inaccessible outcrops of pyroclastic and epiclast... more We present a new tool for the textural study of inaccessible outcrops of pyroclastic and epiclastic deposits. The new method, called Laser Remote Optical Granulometry (LROG), is based on high resolution tele-photography and stereologic techniques. LROG consists on taking several pictures of the outcrop with a high resolution CCD camera coupled to a small aperture telescope that can be placed several tenths of meters away. The scale of the image is obtained projecting an equilateral triangle with known size on the outcrop by means of three laser beams. The LROG allows the measurement of clasts less than 1 mm in size from a distance of 80 to 100 meters, and can reach much better resolution when operated closer to the outcrop. Perspective distortion can be corrected with the equilateral triangle projected by the lasers. To get high resolution images and remove the effects of air turbulence, hundreds of frames of the same field are captured in rapid sequence and then stacked and averaged with image processing algorithms developed for astronomical imaging. The LROG was validated on the pyroclastic deposits of the Joya Honda maar (San Luis Potosi, Mexico). The LROG provided precise granulometric analysis and vertical granulometric profiles of this pyroclastic sequence, useful to recognize the eruptive history of the volcano. This method can be used for the analysis of any kind of sedimentary deposits in the granulometric range of clasts greater than fine sand. We are improving the LROG to obtain other useful textural information like clast shape and apparent fabric. This method, implemented on a robotic probe could be a promising tool to carry out detailed stratigraphic and sedimentological study of Martian sedimentary successions.

Physical properties of some weathered/altered volcanic rocks and their variation with the degree ... more Physical properties of some weathered/altered volcanic rocks and their variation with the degree of alteration are described in detail. A series of tests was performed to identify and quantify the progressive degradation of the properties: 1) petrographycal and chemical studies; 2) effective (η e ) and total porosity (η t ) measurements and 3D pore reconstruction 3) ultrasonic pulse velocity and spatial attenuation (α s ) measurements. Four different volcanic lithologies have been tested: i) trachytic lava with abundant crystals; ii) pyroclastic deposits, with lava clasts and pumice elements; iii) green tuff, made prevalently of pumice clasts; and iv) non-welded ignimbrite deposits. Chemical indices of weathering (CIW) reveal large differences (42.73b Chemical Index of Alteration [CIA]b 69.24) not only between lithotypes, but also between samples. These differences are reflected by physical properties, in particular η t (6.0b η t from X-ray tomography imagesb 49.8%), η e (11.0b η e from mercury porosimeterb 65.0%) and shear wave velocity values (0.50b V s b 2.90 km/s). Pore network evolution with alteration for each lithology is well documented by fractal dimension (D) and α s . Mean values of porosity are strictly related to P and S wave velocity (V p and V s ) and the degree of alteration. Values of CIA are well correlated with the degradation trend exhibited by measured physical properties. The combination of techniques to measure the η t and η e provides a good estimate of grain size and pore size distribution and rock structure. Defects and particular characteristics in the rock sample (e.g. micro-fractures, voids, cavities and orientation and sizes of certain minerals and clasts) are revealed by α s values: the smaller the α s the more homogeneous and less altered is the sample.