We present a collection of pictures of the coseismic secondary geological effects produced on the... more We present a collection of pictures of the coseismic secondary geological effects produced on the environment by the 2012 Emilia seismic sequence in northern Italy. The May-June 2012 sequence struck a broad area located in the Po Plain region, causing 26 deaths and hundreds of injured, 15.000 homeless, severe damage of historical centres and industrial areas, and an estimated economic toll of ~2 billion of euros. The sequence included two mainshocks (Figure 1): the first one, with ML 5.9, occurred on May 20 between Finale Emilia, S. Felice sul Panaro and S. Martino Spino; the second one, with ML 5.8, occurred 12 km southwest of the previous mainshock on May 29. Both the mainshocks occurred on about E-W trending, S dipping blind thrust faults; the whole aftershocks area extends in an E-W direction for more than 50 km and includes five ML≥5.0 events and more than 1800 ML>1.5 events. Ground cracks and liquefactions were certainly the most relevant coseismic geological effects observ...
We reconstruct the tectonic framework of the 24 August 2016, Amatrice earthquake. At least three ... more We reconstruct the tectonic framework of the 24 August 2016, Amatrice earthquake. At least three main faults, including an older thrust fault (Sibillini Thrust), played an active role in the sequence. The mainshock nucleated and propagated along an extensional fault located in the footwall of the Sibillini Thrust, but due to the preliminary nature of the data the role of this thrust is still unclear. We illustrate two competing solutions: 1) the coseismic rupture started along an extensional fault and then partially used the thrust plane in extensional motion; 2) the thrust fault acted as an upper barrier to the propagation of the mainshock rupture, but was partially reactivated during the aftershock sequence. In both cases our tectonic reconstruction suggests an active role of the thrust fault, providing yet another example of how structures inherited from older tectonic phases may control the mainshock ruptures and the long-term evolution of younger seismogenic faults.
Page 1. Umberto Fracassi*, Paola Vannoli**, Pierfrancesco Burrato*, Roberto Basili*, Mara M. Tibe... more Page 1. Umberto Fracassi*, Paola Vannoli**, Pierfrancesco Burrato*, Roberto Basili*, Mara M. Tiberti*, Daniela Di Bucci° and Gianluca Valensise* * Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 ...
In December 1456-January 1457 a major earthquake sequence took place across the central and south... more In December 1456-January 1457 a major earthquake sequence took place across the central and southern Apennines (southern Italy, Calabrian Arc excluded), including southeastern Apulia. A recent re-evaluation of the (a) revised damage pattern for this multiple earthquake, (b) deeper seismicity of the southern Apennines – Adriatic foreland interface and (c) deep-seated regional E-W structures, led to the identification of at least four seismogenic sources, responsible for the main sub-events of the multiple 1456 earthquake.
Earth’s hydrocarbon degassing through gas-oil seeps, mud volcanoes and diffuse microseepage is a ... more Earth’s hydrocarbon degassing through gas-oil seeps, mud volcanoes and diffuse microseepage is a major natural source of methane (CH4) to the atmosphere. While carbon dioxide degassing is typically associated with extensional tectonics, volcanoes, and geothermal areas, CH4 seepage mostly occurs in petroleum-bearing sedimentary basins, but the role of tectonics in degassing is known only for some case studies at local scale. Here, we perform a global scale geospatial analysis to assess how the presence of hydrocarbon fields, basin geodynamics and the type of faults control CH4 seepage. Combining georeferenced data of global inventories of onshore seeps, faults, sedimentary basins, petroleum fields and heat flow, we find that hydrocarbon seeps prevail in petroleum fields within convergent basins with heat flow ≤ 98 mW m−2, and along any type of brittle tectonic structure, mostly in reverse fault settings. Areas potentially hosting additional seeps and microseepage are identified throu...
Abstract Large earthquakes occur rather orderly in space and time; hence they can be somehow anti... more Abstract Large earthquakes occur rather orderly in space and time; hence they can be somehow anticipated, and their effects can be projected into the future. The modern practice of seismic hazard assessment rests on these principles and may rely on them, but also requires a detailed knowledge of the location and characteristics of individual earthquake sources. We discuss how this knowledge base can be constructed, with an eye on the geological history, which provides a record of the faults capable of generating large earthquakes, and one on the human history, which supplies evidence for whether, where and how these faults have actually caused damaging earthquakes in the past. How do these two records interact with each other? It is now accepted that identifying active and potentially seismogenic faults in Italy is especially hard. The geological record may be clear and honest when dealing with processes at the scale of several million years, but can be very difficult to decipher if we are concerned with contemporary geological processes, such as earthquakes. Shortening the tim E-W indow of observation of earthquake activity is why Historical Seismology is so crucial for constructing a seismogenic source model. To this end we exploited a number of key Italian destructive earthquakes, each of which illuminates a recent geological process that may not offer a discernible surface signature. Our findings led us to reconsider the tectonic style of large areas, changed our perception of their earthquake potential, hinted at the existence of unknown seismogenic zones, and even led to downsizing the magnitude of the largest Italian historical earthquakes. We maintain that the complexity of the geological setting may be counterbalanced by the richness of the historical earthquake record. We also believe that our experience in the combined investigation of Italy’s historical earthquakes and seismogenic sources may be replicated in all earthquake-prone countries that exhibit a history of human settlement throughout the millennia.
We show and discuss the similarities among the 2016 Amatrice (Mw 6.0), 1997 Colfiorito-Sellano (M... more We show and discuss the similarities among the 2016 Amatrice (Mw 6.0), 1997 Colfiorito-Sellano (Mw 6.0-5.6) and 2009 L’Aquila (Mw 6.3) earthquakes. They all occurred along the crest of the central Apennines and were caused by shallow dipping faults between 3 and 10 km depth, as shown by their characteristic InSAR signature. We contend that these earthquakes delineate a seismogenic style that is characteristic of this portion of the central Apennines, where the upward propagation of seismogenic faults is hindered by the presence of pre-existing regional thrusts. This leads to an effective decoupling between the deeper seismogenic portion of the upper crust and its uppermost 3 km.The decoupling implies that active faults mapped at the surface do not connect with the seismogenic sources, and that their evolution may be controlled by passive readjustments to coseismic strains or even by purely gravitational motions. Seismic hazard analyses and estimates based on such faults should hence...
<p>Bare twenty years into the XXI century &... more <p>Bare twenty years into the XXI century – and what a treat. Damaging earthquakes with regional impact, climate extremes disrupting weather cycles, water shortages in high-income regions, scarcer (and costlier) energy and mineral resources, rising population. Add a slice of global geopolitical instabilities – even where one would never expect to report them from. And, well, why not: a novel pathogen, so little yet so commanding that the world is still vying with it.</p><p>Natural hazards and anthropogenic factors interact in multiple ways and across various scales, close or afar, in time and space. They interweave a web of complexities that can appear deceitful, capricious, or otherwise overwhelming to the citizens of contemporary societies – even in statistically affluent and educated ones. There comes the role of geosciences, from paleontology to high-atmosphere physics, from energy to oceanography, from the solid to the not so solid earth. There comes their transformative, instrumental task – as new and as pressing as ever.</p><p>Geosciences are not (and will not) what they used to be, bound as they are to glean lessons learned from the past to provide insight into the future. Geoscientists were once thought to study ancient rocks, fiddle with very slow-moving tectonic plates, and bantering about invisible earth’s features, too large, or too deep, or too far away to even imagine for us earthlings. But this is no longer the case – and maybe never has been. At the core of geosciences’ interests lies Nature, for what it is – with all its grand size, seemingly slow processes that unveil sudden effects, complex interactions among forces and bodies across distances and time. These prove to be paramount tools to probe a world perceived as inscrutable, increasingly richer in risks and poorer in resources.</p><p>Therefore, tools of yesterday’s intellectual quests prove instrumental to decipher tomorrow’s societal issues, such as:</p><p>- The long records of natural events (hazards);<br>- Far-flung origins (our solar system and the universe);<br>- Far-reaching effects (feedback, periodicity, and recurrence times);<br>- Need to forecast (or at least account for) the irregular behaviors of modern phenomena (not always known or detectable by current means).</p><p>The knowledge of compounded risks of natural origin provides an outlook on where and what to call for enduring communities. This applies also to risks resulting from interaction among natural events and anthropogenic components. Since natural phenomena embed complexities due to multiple variables and intrinsic feedback, interaction among natural and non-natural ones brings novel issues, requiring a remarkably broad outlook – global and beyond. The natural consequence is then to envision natural risks against population distribution, spatial extents of natural resources, size, and time window of induced effects.</p><p>Picking a selection of examples, this talk thus tries to put into perspective:</p><p>- Hazards stemming from multiple, at times unpredictable sources;<br>- The precious role of geosciences to decipher them – and to forecast them;<br>- The complexity of natural hazards, the flexibility of human planning;<br>- Modern issues challenging societies and economies – today, tomorrow, and thereafter.</p>
We present a collection of pictures of the coseismic secondary geological effects produced on the... more We present a collection of pictures of the coseismic secondary geological effects produced on the environment by the 2012 Emilia seismic sequence in northern Italy. The May-June 2012 sequence struck a broad area located in the Po Plain region, causing 26 deaths and hundreds of injured, 15.000 homeless, severe damage of historical centres and industrial areas, and an estimated economic toll of ~2 billion of euros. The sequence included two mainshocks (Figure 1): the first one, with ML 5.9, occurred on May 20 between Finale Emilia, S. Felice sul Panaro and S. Martino Spino; the second one, with ML 5.8, occurred 12 km southwest of the previous mainshock on May 29. Both the mainshocks occurred on about E-W trending, S dipping blind thrust faults; the whole aftershocks area extends in an E-W direction for more than 50 km and includes five ML≥5.0 events and more than 1800 ML>1.5 events. Ground cracks and liquefactions were certainly the most relevant coseismic geological effects observ...
We reconstruct the tectonic framework of the 24 August 2016, Amatrice earthquake. At least three ... more We reconstruct the tectonic framework of the 24 August 2016, Amatrice earthquake. At least three main faults, including an older thrust fault (Sibillini Thrust), played an active role in the sequence. The mainshock nucleated and propagated along an extensional fault located in the footwall of the Sibillini Thrust, but due to the preliminary nature of the data the role of this thrust is still unclear. We illustrate two competing solutions: 1) the coseismic rupture started along an extensional fault and then partially used the thrust plane in extensional motion; 2) the thrust fault acted as an upper barrier to the propagation of the mainshock rupture, but was partially reactivated during the aftershock sequence. In both cases our tectonic reconstruction suggests an active role of the thrust fault, providing yet another example of how structures inherited from older tectonic phases may control the mainshock ruptures and the long-term evolution of younger seismogenic faults.
Page 1. Umberto Fracassi*, Paola Vannoli**, Pierfrancesco Burrato*, Roberto Basili*, Mara M. Tibe... more Page 1. Umberto Fracassi*, Paola Vannoli**, Pierfrancesco Burrato*, Roberto Basili*, Mara M. Tiberti*, Daniela Di Bucci° and Gianluca Valensise* * Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 ...
In December 1456-January 1457 a major earthquake sequence took place across the central and south... more In December 1456-January 1457 a major earthquake sequence took place across the central and southern Apennines (southern Italy, Calabrian Arc excluded), including southeastern Apulia. A recent re-evaluation of the (a) revised damage pattern for this multiple earthquake, (b) deeper seismicity of the southern Apennines – Adriatic foreland interface and (c) deep-seated regional E-W structures, led to the identification of at least four seismogenic sources, responsible for the main sub-events of the multiple 1456 earthquake.
Earth’s hydrocarbon degassing through gas-oil seeps, mud volcanoes and diffuse microseepage is a ... more Earth’s hydrocarbon degassing through gas-oil seeps, mud volcanoes and diffuse microseepage is a major natural source of methane (CH4) to the atmosphere. While carbon dioxide degassing is typically associated with extensional tectonics, volcanoes, and geothermal areas, CH4 seepage mostly occurs in petroleum-bearing sedimentary basins, but the role of tectonics in degassing is known only for some case studies at local scale. Here, we perform a global scale geospatial analysis to assess how the presence of hydrocarbon fields, basin geodynamics and the type of faults control CH4 seepage. Combining georeferenced data of global inventories of onshore seeps, faults, sedimentary basins, petroleum fields and heat flow, we find that hydrocarbon seeps prevail in petroleum fields within convergent basins with heat flow ≤ 98 mW m−2, and along any type of brittle tectonic structure, mostly in reverse fault settings. Areas potentially hosting additional seeps and microseepage are identified throu...
Abstract Large earthquakes occur rather orderly in space and time; hence they can be somehow anti... more Abstract Large earthquakes occur rather orderly in space and time; hence they can be somehow anticipated, and their effects can be projected into the future. The modern practice of seismic hazard assessment rests on these principles and may rely on them, but also requires a detailed knowledge of the location and characteristics of individual earthquake sources. We discuss how this knowledge base can be constructed, with an eye on the geological history, which provides a record of the faults capable of generating large earthquakes, and one on the human history, which supplies evidence for whether, where and how these faults have actually caused damaging earthquakes in the past. How do these two records interact with each other? It is now accepted that identifying active and potentially seismogenic faults in Italy is especially hard. The geological record may be clear and honest when dealing with processes at the scale of several million years, but can be very difficult to decipher if we are concerned with contemporary geological processes, such as earthquakes. Shortening the tim E-W indow of observation of earthquake activity is why Historical Seismology is so crucial for constructing a seismogenic source model. To this end we exploited a number of key Italian destructive earthquakes, each of which illuminates a recent geological process that may not offer a discernible surface signature. Our findings led us to reconsider the tectonic style of large areas, changed our perception of their earthquake potential, hinted at the existence of unknown seismogenic zones, and even led to downsizing the magnitude of the largest Italian historical earthquakes. We maintain that the complexity of the geological setting may be counterbalanced by the richness of the historical earthquake record. We also believe that our experience in the combined investigation of Italy’s historical earthquakes and seismogenic sources may be replicated in all earthquake-prone countries that exhibit a history of human settlement throughout the millennia.
We show and discuss the similarities among the 2016 Amatrice (Mw 6.0), 1997 Colfiorito-Sellano (M... more We show and discuss the similarities among the 2016 Amatrice (Mw 6.0), 1997 Colfiorito-Sellano (Mw 6.0-5.6) and 2009 L’Aquila (Mw 6.3) earthquakes. They all occurred along the crest of the central Apennines and were caused by shallow dipping faults between 3 and 10 km depth, as shown by their characteristic InSAR signature. We contend that these earthquakes delineate a seismogenic style that is characteristic of this portion of the central Apennines, where the upward propagation of seismogenic faults is hindered by the presence of pre-existing regional thrusts. This leads to an effective decoupling between the deeper seismogenic portion of the upper crust and its uppermost 3 km.The decoupling implies that active faults mapped at the surface do not connect with the seismogenic sources, and that their evolution may be controlled by passive readjustments to coseismic strains or even by purely gravitational motions. Seismic hazard analyses and estimates based on such faults should hence...
<p>Bare twenty years into the XXI century &... more <p>Bare twenty years into the XXI century – and what a treat. Damaging earthquakes with regional impact, climate extremes disrupting weather cycles, water shortages in high-income regions, scarcer (and costlier) energy and mineral resources, rising population. Add a slice of global geopolitical instabilities – even where one would never expect to report them from. And, well, why not: a novel pathogen, so little yet so commanding that the world is still vying with it.</p><p>Natural hazards and anthropogenic factors interact in multiple ways and across various scales, close or afar, in time and space. They interweave a web of complexities that can appear deceitful, capricious, or otherwise overwhelming to the citizens of contemporary societies – even in statistically affluent and educated ones. There comes the role of geosciences, from paleontology to high-atmosphere physics, from energy to oceanography, from the solid to the not so solid earth. There comes their transformative, instrumental task – as new and as pressing as ever.</p><p>Geosciences are not (and will not) what they used to be, bound as they are to glean lessons learned from the past to provide insight into the future. Geoscientists were once thought to study ancient rocks, fiddle with very slow-moving tectonic plates, and bantering about invisible earth’s features, too large, or too deep, or too far away to even imagine for us earthlings. But this is no longer the case – and maybe never has been. At the core of geosciences’ interests lies Nature, for what it is – with all its grand size, seemingly slow processes that unveil sudden effects, complex interactions among forces and bodies across distances and time. These prove to be paramount tools to probe a world perceived as inscrutable, increasingly richer in risks and poorer in resources.</p><p>Therefore, tools of yesterday’s intellectual quests prove instrumental to decipher tomorrow’s societal issues, such as:</p><p>- The long records of natural events (hazards);<br>- Far-flung origins (our solar system and the universe);<br>- Far-reaching effects (feedback, periodicity, and recurrence times);<br>- Need to forecast (or at least account for) the irregular behaviors of modern phenomena (not always known or detectable by current means).</p><p>The knowledge of compounded risks of natural origin provides an outlook on where and what to call for enduring communities. This applies also to risks resulting from interaction among natural events and anthropogenic components. Since natural phenomena embed complexities due to multiple variables and intrinsic feedback, interaction among natural and non-natural ones brings novel issues, requiring a remarkably broad outlook – global and beyond. The natural consequence is then to envision natural risks against population distribution, spatial extents of natural resources, size, and time window of induced effects.</p><p>Picking a selection of examples, this talk thus tries to put into perspective:</p><p>- Hazards stemming from multiple, at times unpredictable sources;<br>- The precious role of geosciences to decipher them – and to forecast them;<br>- The complexity of natural hazards, the flexibility of human planning;<br>- Modern issues challenging societies and economies – today, tomorrow, and thereafter.</p>
Climate change affects human activities, including tourism across various sectors and time frames... more Climate change affects human activities, including tourism across various sectors and time frames. The winter tourism industry, dependent on low temperatures, faces significant impacts. This paper reviews the implications of climate change on winter tourism, emphasising challenges for activities like skiing and snowboarding, which rely on consistent snowfall and low temperatures. As the climate changes, these once taken-for-granted conditions are no longer as commonplace. Through a comprehensive review supported by up-to-date satellite imagery, this paper presents evidence suggesting that the reliability of winter snow is decreasing, with findings revealing a progressive reduction in snow levels associated with temperature and precipitation changes in some regions. The analysis underscores the need for concerted efforts by stakeholders who must recognize the reality of diminishing snow availability and work towards understanding the specific changes in snow patterns. This should involve multi-risk and multi-instrument assessments, including ongoing satellite data monitoring to track snow cover changes. The practical implications for sports activities and the tourism industry reliant on snow involve addressing challenges by diversifying offerings. This includes developing alternative winter tourism activities less dependent on snow, such as winter hiking, nature walks, or cultural experiences.
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