Catalogues of historical earthquakes in Italy

A complete survey of historical earthquake investigation in Italy cannot be compressed into a few pages, since it would entail making a summary of widely different phases of research (performed by past scholars and by contemporary scientists and historians) and taking into account the widely different historical contexts, methodological assumptions and critical awareness of each of them. This short note only purposes to chart the main stages of the progress made by Italian historical seismology, from the late 17th century compilation by Bonito(1691) up to the latest parametric catalogue (Working Group CPTI, 1999)

Percorsi formativi per la riduzione del rischio: il progetto EDURISK

L'obiettivo di un progetto di educazione ambientale è modificare i comportamenti individuali e collettivi; tale obiettivo è ambizioso, ma non può essere eluso quando si affronta il tema dei rischi naturali e dei loro potenziali effetti distruttivi. La stessa distinzione epistemologica, ben chiara nella lingua inglese, fra hazard e risk, più incerta nella lingua italiana fra pericolo (o pericolosità) e rischio, include la consapevolezza che il rischio è determinato dall'azione umana. Educare al rischio significa promuovere la coscienza del rischio quale elemento della vita quotidiana: la conoscenza della vulnerabilità dell'ambiente fisico e costruito, acquisita facendone esperienza, è la chiave per promuovere comportamenti individuali e sociali positivi e ridurre il rischio

A che santo votarsi. L’influsso dei grandi terremoti del 1703 sulla cultura popolare

La paura e il suo contraltare, la ricerca di rassicurazione e protezione, sono all’origine delle più svariate manifestazioni umane: riti, feste, interdetti, comportamenti pubblici e privati, molto insomma di quanto si riassume nell’espressione generica “le mentalità”1. Questo saggio è un primo abbozzo di storia delle risposte a una paura specifica: quella suscitata dai grandi terremoti del 1703, la maggior catastrofe sismica che abbia colpito l’Italia centrale in età moderna. Il suo scopo è cercare di capire se le risposte alla paura del 1703 siano rientrate nella norma di un contesto di modelli di comportamento consolidati nel tempo o se vi abbiano introdotto degli elementi di novità: come e quanto, insomma, i terremoti del 1703 abbiano influito sulla cultura popolare. Usiamo l’espressione “cultura popolare” in senso antropologico, intendendo per “cultura” l’insieme dei valori e modalità di giudizio, percezione ed espressione che dà forma e colore a un dato ambito sociale e dando all’aggettivo “popolare” l’accezione di “comune a una vasta maggioranza”. Siamo a un crocevia tra più discipline: il tema è dell’antropologia storica, i metodi sono storici e a far da sottofondo c’è una lunga consuetudine di lavoro nel campo della sismologia storica2, senza la quale questo saggio non sarebbe mai stato neanche pensato. Il soggetto è vasto, elevato il rischio di ripetere cose note ai lettori o magari ricordate in altri saggi presenti in questo volume: confidiamo nell’indulgenza dei lettori per un testo che in fondo vuole essere solo la messa a punto di una serie di problemi e spunti di ricerca, ciascuno meritevole di trattazione più estesa e approfondita di quanto non sia possibile entro i limiti di questo saggio e che proponiamo ai colleghi ricercatori come degno soggetto di un’indagine storica in larga misura ancora da fare

Macroseismology: the lessons learnt from the 1997/98 Colfiorito seismic sequence

The seismic sequence of the Umbria-Marche Apennines was a dramatic moment for the population involved; at the same time, it provided a unique occasion for the Italian scientific community and for the national civil protection to assess their respective abilities in understanding and managing the event. Furthermore, macroseismology (including historical seismology) has knowingly confronted important methodological problems, such as the procedures for assigning macroseismic intensity, the use of the macroseismic scale, the impossibility of distinguishing the effects of earthquakes following closely in both space and time, within such a complex sequence. Starting from the analysis of the problems that were faced after the 1997/98 Umbria- Marche earthquakes, as during the following seismic crises over the last 10 years, we propose some considerations on the lessons we have learnt from that seismic sequence

Educational strategies to reduce risk: a choice of social responsibility

This work develops a critical reflection on the activities for information, training and education conducted by a group of researchers of the INGV in recent years. In particular, our analysis, from an epistemological point of view, is between:  science outreach, the link between science and the world;  science teaching and its role of contact between science and school;  risk education, imaged as a process able to develop a culture of risk in relation to the territory in which we live. These issues are critically analyzed on the basis of experience gained since 1995. The educational methodologies tested in "peacetime", out of seismic events, with the EDURISK Project are compared with those experienced during the emergency in Abruzzo. Increasingly today, we refer to prevention as a primary strategy of defense against risk. But very often the responsibility of making prevention falls on the others as government, institutions, local authorities and the citizen perceive themselves as powerless against the inevitability of natural events and refer to the rulers for the implementation of effective prevention policies. As researchers, what are the most effective actions we can take to influence the risk reduction and motivate the choices of people? The effectiveness of our interventions must be based on scientific information, on a specific training, or must be reached to develop values, actions, awareness? Our interventions must be oriented and developed to inform, to train or to educate

Changes and challenges following the 1997 Colfiorito earthquake: the evolution of the use of the Internet for large seismic events

The September 26, 1997 Central Italy earthquake represents the first Italian large seismic event on the occasion of which Internet was intensively exploited to exchange and disseminate data, information and news. The paper illustrates how national and international seismological institutions disseminate information about earthquakes ten years ago. A web evolution is sketched, and some features that can be of interest today in the seismological community are presented

The 1561 Earthquake(s) in Southern Italy: New Insights into a Complex Seismic Sequence

In the summer of 1561, a strong seismic sequence struck southern Italy, then the Spanish-ruled Kingdom of Naples. Both the Italian seismological tradition and the latest catalogues locate it in the Vallo di Diano (Diano Valley), a low-seismicity intermontane basin 100 km south-east of Naples. We explore the hypothesis that current perception of the 1561 earthquake is distorted by the nature of the historical dataset from which its parameters have been assessed, and which mostly derive from a single—albeit very detailed—primary source. We present and discuss several previously unconsidered original accounts. Our results cast doubts on the traditional interpretation of the earthquake, which could have been either one Vallo di Diano mainshock or several strong earthquakes within a time/space window compact enough for contemporary viewers to perceive them as one. Unquestionably, there is much more to the 1561 earthquake(s) than previously appeared. We hope that this groundbreaking effort will rekindle the interest of the seismological community in this seismic episode, our knowledge of which is still far from complete

A 17th century damaging earthquake cluster in the Gargano area and its implications on the understanding of local seismicity

The existence of a significant earthquake cluster located in the Gargano area (Southern Italy) between 1627 and 1688 A.D. was discovered by an investigation following innovative criteria (information on local seismicity was sought for in non-local historical records of a special kind – i.e. diplomatic and journalistic serial sources - as opposed to the more traditional approach of thoroughly analysing any available local historical records). The events belonging to the 17th century cluster are described, in the context of a survey of the current state of knowledge on historical Gargano seismicity including a critical evaluation of previous studies and a concise review of those earthquakes still lacking adequate studies. Hypotheses on the seismotectonic effects of the event and its influences on the evaluation of hazard are also formulated

Can We Consider the 1951 Caviaga (Northern Italy) Earthquakes as Noninduced Events?

On the night between May 15 and 16, 1951, two moderate earthquakes with estimated magnitudes of M 5.4 and 4.5 occurred in northern Italy, about 40 km southeast of Milan, close to the small town of Caviaga. They were recorded by several observatories worldwide, as reported by the International Seismological Summary (ISS) Bulletin. Despite the moderate magnitudes, these two events caught the attention of seismologists and have been studied in detail, in particular by Caloi et al. (1956), because they were close to Caviaga, in an area that was assumed to be aseismic. Moreover, their shallow hypocenters (ca. 5 km in Caloi et al., 1956) indicated a possible anthropogenic source, related to wells for gas withdrawal. In the absence of any further discussion or revision of the original study by Caloi et al. (1956), the Caviaga earthquakes have been included in several compilations of induced seismicity, and they have been generally accepted as cases of anthropogenic events. After 60 years it is possible to revisit this interpretation using improved computational techniques, the available high-resolution data, enriched historical catalogs, and a deeper understanding of the regional seismotectonic and crustal structure. The focus of this study is the relocation of these two events with the use of modern hypocentral location methods, and the analysis of the historical seismicity of the area. A complete seismic source parameterization is out of the scope of this preliminary study. In the following we describe the regional geological setting and the gas reservoir characterization, introduce the context of historical seismicity, provide a description of the main shock relocation, discuss the uncertainties of the hypocentral parameters and estimate the variation of the stress field in proximity to wells. We consider this revision necessary to be able to discuss the possibility that these two events were not induced by human activity, as well as to improve the quality of the dataset for decision makers involved in risk evaluation