Seismic waves and acoustic waves: from earthquake to music

INGV is currently the largest European scientific institution dealing with Earth Sciences research and real-time surveillance, early warning, and forecast activities in geophysics and volcanology. The Laboratorio Didattica e Divulgazione Scientifica of INGV organizes every year rich educational and outreach activities with schools of different levels and with general public to convey scientific knowledge and to promote research on science and nature, focusing on volcanic and seismic hazard. The activities encompass a wide variety of formats, such as the opening of our labs to schools for guided visits, contributing to national (e.g., the Italian “Week of the Scientific Culture”, launched by the Ministry of Education and Research) and international (e.g., the European “Night of the Researchers”) events, editing educational videos, creating multimedia tools also available on the Web. Moreover, we contribute to expositions and science festivals organizing exhibitions with experiments, models, and exhibits designed to teaching and learning geophysics. Finally, we offer guided visits to the control rooms run by our Institute, which ensures the round-the-clock volcanic and seismic surveillance of the whole Italian territory. During the Week of the Scientific Culture and the Night of the Researchers we opened our Institute to the general public, in order to show our laboratories, to talk about new researches on Earth Sciences and to explain the volcanic and seismic risk and the related surveillance activities. These initiatives are widely appreciated by the community and we organized special events with the aim to inspire curiosity toward scientific research, and to facilitate the approach of the general public to science and nature. The special event of the 2010 programmes was a scientific-musical format: Seismic waves and acoustic waves, from earthquake to music. The aim of this project was to involve the public in scientific events offering happening where the scientific language is mediate through the language of the music. In this way, scientific phenomenon are brought in using emotion, making easier the understanding of the scientific themes. The format started with short lectures on earthquake and seismic wave propagation to move on the comparison between the seismic waves and the acoustic waves. We used seismograms, acoustic instruments, the voice, and the Earth sounds to explain the relation between earthquake waves and music. The scientific talks were organized to create a trail that, through emotion and curiosity, guides the public to the discovery and comprehension of the scientific phenomenon. The final part of the event was devoted to classical/jazz/blues live concerts performed by groups and ensembles, some of them arranged by INGV researchers. As a general result, thanks to this project we joined science and community, merging the INGV mission with the public expectation. This scientific-musical format represented an experimental outreach project, new, stimulating, and appreciated by the audience that can be used as good practice of scientific divulgation

TITLE: Looking for surface faulting ancestors of the L’Aquila April 6, 2009 event: preliminary paleoseismological data and seismic hazard implications

The occurrence of the Mw 6.3, April 6, 2009 earthquake has highlighted how critical is the knowledge of the location and of the characteristics of the active faults in a seismic region. This is true not only as a contribution to the seismic hazard assessment but also for the local planning of residential areas, plants and infrastructures. The 2009 earthquake occurred on the Paganica normal fault (PF hereinafter) and produced 3 km-long, maximum 0.1 m-high surface rupture along its central section, and secondary slip along nearby tectonic structures. The PF consists of a prominent morphologic scarp formed by the tectonic juxtaposition of Pliocene-middle Pleistocene and late Pleistocene alluvial deposits, and by lower scarps in late Pleistocene-Holocene deposits. The fault, NW-SE striking and SW dipping, runs for a total length of about 20 km along the NE side of the Aterno River valley, a graben-type basin bounded by marked antithetic faults. The limited extent and the small throw of the 2009 surface ruptures, when compared to the size of the Paganica long-term fault scarp, suggest that the PF probably experienced larger Magnitude earthquakes than the 2009 seismic event. Thus, although the April 6, 2009 earthquake and associated surface faulting caused loss of lives and major damage, we believe that this event does not fully characterize the seismic hazard of the area. Therefore, a campaign of paleoseismological investigations is underway with the aim of defining the Max Magnitude, the average rate of displacement and the frequency of seismic events on the PF and on the nearby faults. An amazing “coseismic” trench, caved by the overpressure produced by the broken pipe of an aqueduct, provided the exposure of a 30-m wide fault zone of the PF. We show the preliminary results from the analysis of this site, as well as from other sites along the PF. In addition, we also present preliminary paleoseismological data from the antithetic Fossa fault. A major finding at this early stage of our field campaign is the recognition of large displacements (0.5 to 1 m) associated to individual events affecting deposits of Holocene age based on radiocarbon dating and pottery content

First appraisal to define prospective seismogenic sources from historical earthquake damages in southern Upper Rhine Graben

International audienceThe southern portion of the Upper Rhine Graben, a major oblique rift among France, Germany and Switzerland, shows a weak instrumental seismic record despite its remarkable physiographic imprint within the Northern Alpine foreland. Since traces of active deformation can be found in this region and based on experience in other European areas with high seismic hazard and dense population, we searched for past earthquakes recorded in historical catalogues. Based on the fact that tectonic deformation cumulates through geological time and considering that long-term effects tend to leave characteristic signatures on present-day landscape arrangement, our goal was to identify faults that could have caused the damage of recorded historical events.We isolated five main earthquakes, of moderate Richter magnitude, essentially located on the E flank of the graben (as is the case with recent seismic activity). To such events, we were able to associate a specific prospective structure through the use of a procedure thus far successfully employed in Southern European contexts. We concentrated on three events which showed (a) notable sensitivity to the density of the historical felt reports and (b) accordance with on-going subtle deformation pattern. Another, most relevant earthquake (M 5.5) yielded a promising match with the known deformation network in the region.As a template to better constrain earthquake cycle and damage potential, historical seismicity offers an invaluable tool, since it contains a specific record, although not always unambiguous. Cross-checking such data with pertinent geological information allows to devise a realistic fault geometry capable of being responsible for a specific seismic event

From Historical Seismology to seismogenic source models, 20 years on: Excerpts from the Italian experience

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 and how such damaging earthquakes have occurred 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 is very difficult to decipher if we are concerned with contemporary geological processes, such as the earthquakes. Shortening the time-window 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 potential 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.Published2281892T. Deformazione crostale attiva4T. Sismicità dell'Italia6T. Studi di pericolosità sismica e da maremotoJCR Journa

Is blind faulting truly invisible? Tectonic-controlled drainage evolution in the epicentral area of the May 2012, Emilia-Romagna earthquake sequence (northern Italy)

For decades, alluvial plains have been the areas of the fastest population growth over most of the globe. Modern societies demand growing extensions of flat and easily accessible land to accommodate the swelling urban areas, booming industrial districts, large power plants, and multi-runway airports. But how can we tell if such flat areas hide large active faults? How can we assign a significant pre-instrumental earthquake to its causative source? In other words, how can modern societies deal with buried, that is to say, 'invisible' faults, and with the elusiveness of the hazards they can pose? The issue of blind faulting became widely debated in the Earth sciences community in 1989, following the publication of a summary on a sequence of 'hidden earthquakes' that hit central and southern California, USA, between 1983 and 1987, and following the October 17, 1989, Loma Prieta, California, earthquake (Mw 6.9). These earthquakes shattered the accepted belief that large earthquakes are associated with large topographic contrasts; i.e., that they usually take place in mountainous terrains, and that their causative faults are expressed at the surface. Stein and Yeats [1989] spelled out clearly that "...large earthquakes can take place not only on faults that cut the Earth's surface, but also on 'blind' faults under folded terrain". Due to the growing concentrations of population and infrastructures in low topography areas, although such earthquakes might pose comparable hazards, they can come with substantially greater risk than earthquakes that occur in hilly or mountainous terrains. [...

On the (melting) rocks: climate change and the global issue of permafrost depletion

This short communication reports on the pressures posed by climate change on permafrost. The phenomenon of the (melting) rocks, soil, and ground that host permafrost does not just concern a remote stretch of the Arctic north. It is a far larger area than most citizens may realise if looking at an ordinary map projection. Broadly distributed and crucial as it is for the Earth's climate, permafrost thawing due to climate change can affect or upend several aspects associated with life and prosperity on Earth, demanding far greater attention. The loss of permafrost is a global problem that requires a global solution. Greenhouse gas emissions (GHG) must be reduced to slow permafrost's thawing and negative impacts. As such, this short communication aims to catalyse a global debate on this climate change consequential issue, also providing specific suggestions for reducing the impacts of permafrost depletion

Modes of fault reactivation from analogue modeling experiments: implications for the seismotectonics of the southern Adriatic foreland (Italy)

The active tectonics at the front of the Southern Apennines and in the Adriatic foreland is characterized by E–W striking, right-lateral seismogenic faults, interpreted as reactivated inherited discontinuities. The best studied among these is the Molise-Gondola shear zone (MGsz). The interaction of these shear zones with the Apennines chain is not yet clear. To address this open question, we developed a set of scaled analogue experiments, aimed at analyzing: (1) how dextral strike–slip motion along a pre-existing zone of weakness within the foreland propagates toward the surface and affects the orogenic wedge; (2) the propagation of deformation as a function of increasing displacement; (3) any insights on the active tectonics of Southern Italy. Our results stress the primary role played by these inherited structures when reactivated, and confirm that regional E–W dextral shear zones are a plausible way of explaining the seismotectonic setting of the external areas of the Southern Apennine