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

Papers by Gianluca Norini

Research paper thumbnail of Land subsidence, Ground Fissures and Buried Faults: InSAR Monitoring of Ciudad Guzmán (Jalisco, Mexico)

Research paper thumbnail of Miocene faulting in the southwestern Sierra Madre Occidental, Nayarit, Mexico: kinematics and segmentation during the initial rifting of the southern Gulf of California

Revista Mexicana De Ciencias Geologicas, 2014

Research paper thumbnail of Wijbrans et al 2011

Research paper thumbnail of November 16th 2006 Lateral Collapse of South-East Crater on Mount Etna Volcano and Hazard Implication

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

Research paper thumbnail of Numerical modeling of debris avalanches at Nevado de Toluca (Mexico): implications for hazard evaluation and mapping

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

Research paper thumbnail of Caracterización de fallas sismogenéticas en el centro del Cinturón Volcánico Trans – mexicano. Resultados preliminares

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.

Research paper thumbnail of Mapping of the Inabanga Fault in Bohol, Philippines using High Resolution LIDAR Imagery and Field Mapping Verification

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.

Research paper thumbnail of What controls the shallow structure of divergent plate boundaries? Insights from field and modelling data

Research paper thumbnail of Valle del Bove, eastern flank of Etna Volcano: A comprehensive model for the opening of the depression and implications for future hazards

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. ...

Research paper thumbnail of Ground Fracturation in Urban Area: Monitoring of Land Subsidence Controlled by Buried Faults with InSAR Techniques (Ciudad Guzmán: Mexico)

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.

Research paper thumbnail of The Calama–Olacapato–El Toro fault system in the Puna Plateau, Central Andes: Geodynamic implications and stratovolcanoes emplacement

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.

Research paper thumbnail of An overview of experimental models to understand a complex volcanic instability: Application to Mount Etna, Italy

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.

Research paper thumbnail of Analogue modeling of flank instability at Mount Etna: Understanding the driving factors

Journal of Geophysical Research, 2011

Research paper thumbnail of Analogue modelling of flank dynamics at Mount Etna, Italy

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 ...

Research paper thumbnail of Scaled analogue models of dikes propagation and associated surface deformation

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

Research paper thumbnail of The Colima Volcano WebGIS: system acquisition, application and database development in an open-source environment

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 ...

Research paper thumbnail of The Colima Volcano Database: an online tool for a global data access

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 ...

Research paper thumbnail of Laser Remote Optical Granulometry (LROG), a tool for the textural study of inaccessible outcrops: could this method help to study Martian sedimentary successions

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.

Research paper thumbnail of Mars Sedimentology Using Laser Remote Optical Granulometry (LROG

Research paper thumbnail of Influence of alteration on physical properties of volcanic rocks

Research paper thumbnail of Land subsidence, Ground Fissures and Buried Faults: InSAR Monitoring of Ciudad Guzmán (Jalisco, Mexico)

Research paper thumbnail of Miocene faulting in the southwestern Sierra Madre Occidental, Nayarit, Mexico: kinematics and segmentation during the initial rifting of the southern Gulf of California

Revista Mexicana De Ciencias Geologicas, 2014

Research paper thumbnail of Wijbrans et al 2011

Research paper thumbnail of November 16th 2006 Lateral Collapse of South-East Crater on Mount Etna Volcano and Hazard Implication

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

Research paper thumbnail of Numerical modeling of debris avalanches at Nevado de Toluca (Mexico): implications for hazard evaluation and mapping

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

Research paper thumbnail of Caracterización de fallas sismogenéticas en el centro del Cinturón Volcánico Trans – mexicano. Resultados preliminares

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.

Research paper thumbnail of Mapping of the Inabanga Fault in Bohol, Philippines using High Resolution LIDAR Imagery and Field Mapping Verification

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.

Research paper thumbnail of What controls the shallow structure of divergent plate boundaries? Insights from field and modelling data

Research paper thumbnail of Valle del Bove, eastern flank of Etna Volcano: A comprehensive model for the opening of the depression and implications for future hazards

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. ...

Research paper thumbnail of Ground Fracturation in Urban Area: Monitoring of Land Subsidence Controlled by Buried Faults with InSAR Techniques (Ciudad Guzmán: Mexico)

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.

Research paper thumbnail of The Calama–Olacapato–El Toro fault system in the Puna Plateau, Central Andes: Geodynamic implications and stratovolcanoes emplacement

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.

Research paper thumbnail of An overview of experimental models to understand a complex volcanic instability: Application to Mount Etna, Italy

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.

Research paper thumbnail of Analogue modeling of flank instability at Mount Etna: Understanding the driving factors

Journal of Geophysical Research, 2011

Research paper thumbnail of Analogue modelling of flank dynamics at Mount Etna, Italy

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 ...

Research paper thumbnail of Scaled analogue models of dikes propagation and associated surface deformation

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

Research paper thumbnail of The Colima Volcano WebGIS: system acquisition, application and database development in an open-source environment

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 ...

Research paper thumbnail of The Colima Volcano Database: an online tool for a global data access

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 ...

Research paper thumbnail of Laser Remote Optical Granulometry (LROG), a tool for the textural study of inaccessible outcrops: could this method help to study Martian sedimentary successions

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.

Research paper thumbnail of Mars Sedimentology Using Laser Remote Optical Granulometry (LROG

Research paper thumbnail of Influence of alteration on physical properties of volcanic rocks