Guidoboni, Emanuela

The present contribution describes the method of work, the types of source materia] used, and the historio- graphical and historico-eismic tradition of Armenia. The catalogue' s territorial frame of reference is that of socalled historical Armenia (which included part of present Eastern Turkey, and part of present Azerbaijan). The sources belong to different languages and cultures: Armenian, Syriac, Greek, Arab, Persian and Georgian. A comparison of the local sources with those belonging to other cultures enab]es the historical and seismological I"adition of the Mediterl'anean to be "linked" with that of the Iranian p]ateau, traditionally considered as two separate areas. We analyzed historical events listed in the most recent catalogues of earthquakes in the Armenian area compiled by Kondorskaya and Shebalin (1982) and Karapetian (1991). Important and valuable though these catalogues are, they are in need of revision. We found evidence for six hitherto unrecorded seismic events. Numerous errors of dating and location have been corrected, and several new localities and seismic effects have been evidenced. Each modification of the previous catalogues has been documented on the hasis of the historiographical and literary sources and the data from the written sources have been linked with those concerning the history of Armenian cities and architecture (monasteries, churches, episcopal complexes). On the whole. the revised earthquakes seem underestimated in the previous catalogues. The aim of this catalogue is to make a contribution to the knowledge of historical seismicity in Armenia, and at the same time to underline the specific nature of the Armenian case, thus avoiding a procedure which has generally tended to place this area in a marginal position, within the wider field of other research on historical earthquakes.

This paper presents the results of a systematic historical study of the seismic, bradyseismic and eruptive activity of the Campi Flegrei caldera. The aim is to make a revised historical data available for accurate volcanological interpretation, supplying additional data and highlighting spurious previous data. The analysis begins with the supposed 1198 eruption, which did not actually take place. No information is available for the thirteenth and fourteenth centuries. As far as the fifteenth and sixteenth centuries are concerned, only direct sources were examined for this paper, and they include many different types of evidence. The chronological breadth of the analysis has also provided information about the seismic crises and bradyseisms prior to the eruption of 1538. The exceptional nature of this 1538 eruption attracted the attention of intellectuals, diplomats and natural philosophers, who left valuable accounts, which we have analysed, and which include many that are still available in their original manuscript form. The previous studies concerning the 1538 eruption were based on 23 (variously used) sources. We have examined 35 additional sources bringing the overall corpus of sources analysed to 58. The results provide a more precise scenario of events preceding the 1538 eruption, including bradyseismic activity starting from the end of the fifteenth century. The chronology of the phenomena described comprises the core result of this study, and has been constructed so as to clarify the time, location and impact of each event. For the 1538 eruption, a countdown is included which may also have a predictive value. For the last 36 hours before eruption began, the countdown is hour-by-hour. The effects of the eruption and earthquakes on people, structures and society are also described for Pozzuoli, Agnano and Naples. The areas where heavy materials and ash fell are likewise indicated, as well are the earth tremors felt by the population from the eruptive crisis up to 1582.

We present here a compilation of known, reliable, historically documented tsunamis that have affected the Levant coast between about the 14th century B.C. in Syria, up through the 1956 Jaffa tsunami. The list is based on a careful review of published studies and catalogs that have previously reappraised the original contemporaneous sources. In total, 23 events are included within our compilation, whereas 40 other events were found questionable and excluded. We first describe the dependable tsunamis in detail, including their probable source, whether they were generated from a close or distant earthquake source, or whether they were likely the consequence of an earthquake-triggered submarine slump. This is followed by a critical evaluation of the dubious (uncertain) tsunami reports, as an aid to future investigations that may include a search for new data, fieldwork, modeling and hazard assessments. Next, the list is parameterized in accordance with the format used by the tsunami catalog of the European community. Finally, the historical descriptions are used to assess the impact and effects caused by the tsunamis. The most regularly mentioned (about 90%) is a significant change in sea level. Damage and loss of life in coastal cities and harbors are reported for only one third of the events, leading to the conclusion that the majority of tsunamis on the Levant coast may have resulted in only moderate to no damage. Yet, this is not to mean that the Levantine coast is not at risk. The modern coastline is now far more populated and developed than before, and a similar tsunami that resulted in only moderate damage in the past might be more disastrous in the same location at present.

Some earthquakes, particularly the strongest ones, can re-occur within hundreds or thousands of years. Therefore, the areas whose "seismic history" seems to be totally lacking in information are indeed a problem. In the past, these "silences" were interpreted in the simplest way, as an indicator of a low degree of seismicity. More recently, the results of historical research, some geological observations and the limits imposed by the physics of the seismic cycle suggest that this interpretation is wrong and must be overcome by new multi-disciplinary strategies. These strategies will involve the use of both the general pattern offered by the knowledge on the historical seismicity, and the little, though valuable information gleaned from land geology. Similar to these "silent" or "missing" earthquakes are the cases of the "missed" earthquakes which occurred in such historical and territorial conditions that they went completely unnoticed. A third case regards "underrated" earthquakes, reported as events of moderate energy. "Missing", "missed" and "underrated" earthquakes call for some reflection on the problem of completeness in the catalogue, and require innovative research projects. In recent years the Istituto Nazionale di Geofisica and SGA have developed three of such projects. These concern: 1) Sicily in the period between the ninth and thirteenth centuries; 2) the Pollino area (Northern Calabria) before the nineteenth century; 3) the Velino-Sirente massif in the period between the eleventh and fourteenth centuries.

The Catalogue lists earthquakes that occurred in Italy between 461 B.C. and 1997, and earthquakes that occurred in the general Mediterranean area between the VIII century b.C. and the XV century. Italian earthquakes are based on the latest release of the Catalogo dei Forti Terremoti in Italia (Catalogue of Strong Italian Earthquakes), commonly referred to as CFTI3 (Boschi et al., 2000), with subsequent additions and improvements. The CFTI4 contains all Italian earthquakes having epicentral intensity VIII or larger and a selection of smaller earthquakes (total number of earthquakes: 1257). All data supplied in the Catalogue are based on ad hoc historical investigations and on specifically reinterpreted and discussed historical sources. Since its first 1995 release the Catalogo dei Forti Terremoti has been substantially extended and improved with respect to a) the earthquakes analyzed, b) the number of historical sources considered, and c) the number of assessed intensities. Mediterranean earthquakes are based on two catalogues: the Catalogue of Ancient Earthquakes in the Mediterranean area up to the 10th century (Guidoboni et al., 1994), containing 300 earthquakes that involved 19 present-day countries around the Mediterranean, and on the Catalogue of Earthquakes and Tsunamis in the Mediterranean area from the 11th to the 15th century (Guidoboni and Comastri, 2005), containing 383 earthquakes relative to 19 countries. Overall the CFTI4 containes 1,739 earthquakes, 482 of which occurred outside of Italy. Both catalogues report historical sources in their original language. The Catalogue is accessible through a specifically designed web-GIS interface. All commands are easy to use and fully described in English in the Help section. Due to the nature and history of the Catalogue, however, the comment texts that accompany all Italian earthquakes are currently available only in Italian. To allow their visualization in the web-GIS environment of the Catalogue, data on Mediterranean earthquakes have been reorganized following the same standards and format as the data on Italian earthquakes. Nevertheless, some of the information available for Italian earthquakes may not be readily available for all Mediterranean earthquakes. General information on the adopted method of historical research and on the structure and contents of the Catalogue is given in a series of articles published in a special issue of ANNALI DI GEOFISICA (vol.43, N. 4, August 2000) along with CFTI3 (Boschi et al., 2000). Although there have been significant advancements since the year 2000, these articles describe satisfactorily the main research issues, most of which are still the object of scientific debate.

The particular structure of the research into historical seismology found in this catalogue has allowed a lot of information about unknown seismic events to be traced. This new contribution to seismologic knowledge mainly consists in: i) the retrieval and organisation within a coherent framework of documentary evidence of earthquakes that took place between the Middle Ages and the sixteenth century; ii) the improved knowledge of seismic events, even destructive events, which in the past had been "obscured" by large earthquakes; iii) the identification of earthquakes in "silent" seismic areas. The complex elements to be taken into account when dealing with unknown seismic events have been outlined; much "new" information often falls into one of the following categories: simple chronological errors relative to other well-known events; descriptions of other natural phenomena, though defined in texts as "earthquakes" (landslides, hurricanes, tornadoes, etc.); unknown tremors belonging to known seismic periods; tremors that may be connected with events which have been catalogued under incorrect dates and with very approximate estimates of location and intensity. This proves that this was not a real seismic "silence" but a research vacuum.

The authors' aim in the following study is to contribute to the assessment of the seismic hazard of historical cities. From this preliminary analysis the general characteristics of the seismicity affecting Florence and the evaluation of its seismic hazard may be deduced. Florence is a <> city of world tourism, and its extraordinary artistic value and its ability to be utilized constitute a great economic resource. From this perspective, the authors have tackled some aspects of its urban features (demography and main building types, successive phases in the growth of the city, etc.), aimed at the pooling of information as a basis for further, more specific analyses of seismic risk. The study is based on a review of 131 seismic events of potential interest for the site of Florence from the 12th century. In the case of each of these earthquakes, it was possible to verify the real seismic effects sustained, and thus to assess the seismic intensity on the site. This also enabled the limits in the application of the standard attenuation laws of to be checked. Of all the earthquakes analyzed. those which caused the greatest effects on the urban area have also been identified: namely, the earthquake of 28 September 1453. and those of 18 May and 6 June 1895, both with Io=VIII MCS. From their overall analysis the authors have further extrapolated the necessary data to statistically evaluate the probabilities of any future earthquake occurring, according to intensity classes.

The environment is not only the result of what can be seen or planned. There are also some hidden, geologically stable features, such as the ones that cause earthquakes, and that strongly interact with the inhabited world. For their geographical diffusion, the frequency and sheer scope of the damage they cause, earthquakes in Italy represent one of the least resolved aspects in the relationship between residential characteristics and the natural environment. The analysis of the Calabria, as case history, highlights the importance to examine carefully the relationship between strong seismic activity and social and economic development. The lifestyles, use of the territory, expectations concerning safety and the destructiveness of the earthquakes today implies a synergy between different disciplinary contributions. The frequency and the “predictability” of the seismic activity in many Italian areas should make the seismic scenarios a lot less sudden, actually we might even say they could be expected.

Reliable forecasting of the next eruption at Vesuvius is the main scientific factor in defining effective strategies to reduce volcanic risk in one of the most dangerous volcanic areas of the world. In this paper, we apply a recently developed probabilistic code for eruption forecasting to new and independent historical data related to the pre-eruptive phase of the 1631 eruption. The results obtained point out three main issues: (1) the importance of “cold” historical data (according to Guidoboni 2008) related to pre-eruptive phases for evaluating forecasting tools and possibly refining them; (2) the BET_EF code implemented for Vesuvius would have forecasted the 1631 eruption satisfactorily, marking different stages of the pre-eruptive phase; (3) the code shows that pre-eruptive signals that significantly increase the probability of eruption were likely detected more than 2 months before the event.