Alessandra Maramai

The New Catalogue of Italian Tsunamis

A new Italian tsunami catalogue (ITC) is presented here. It contains 67 events, covering the period from the tsunamigenic Plinian eruption of Vesuvius (79AD) until today. It is the result of an intense work of scrutiny of the original sources of data, and integrates and updates the tsunami catalogue by Tinti and Maramai (TMC) published in 1996. With respect to the TMC catalogue, six new events have been added and six have been eliminated, while the 61 events common to both catalogues have been all re-examined and re-evaluated. The ITC fits the criteria adopted for the catalogue of tsunamis in the European region in the framework of the EU projects GITEC (1992–1995) and GITEC-TWO(1996–1998). It is in the form of a digital database, that was implemented through the Visual FoxPro 6.0 DBMS with the main purpose of building a rigorous and easy-to-use working tool for scientists as well as for people involved in hazard and risk reduction in coastal areas. Through the main catalogue screen, the user is allowed to browse the database and to get all the information concerning a selected event (occurrence date, cause, detailed description, references, etc.). Furthermore, by means of functional buttons, the user can perform data extractions according to several key combinations (date, generation, sub-region, tsunami intensity, cause, etc.) and also access the related database of the references containing about 230 entries. In addition to data in the form of text, the ITC also includes a gallery of images documenting tsunami damage and a unique set of analogue tide-gauge records. A further section of statistics provides space and time distribution of the events, tables and histograms. The catalogue is available at the INGV web site http://www.ingv.it/italiantsunamis/tsun.html and can be freely downloaded.

The Gargano promontory: An important Italian seismogenic-tsunamigenic area

Abstract Gargano is a small mountainous promontory protruding into the Southern Adriatic and, from a structural point of view, it is part of the Apulia foreland. Deformative structures, both inland and offshore the promontory, are quite common and can partially be associated with a substantial Quaternary uplifting. Seismogenically this area is well known, because several historical strong earthquakes have been reported to occur here and recent important seismic sequences have been recorded. This paper is a contribution to evaluate the seismogenic as well as the tsunamigenic potential of this region. Particular attention has been given to study the major events, some of which were able to produce tsunamis. The epicenter location of some of these earthquakes computed solely on the basis of macroseismic data would point to focal regions on land, but this is questionable if tsunami generation is taken into account. As regards the tsunamigenic potential, statistical analysis is used to evaluate the local geographical distribution of expected tsunamis and the mean return periods. It is found that large events are expected on average every 228 years, while a tsunami of any size is generated every about 84 years, which is in good agreement with the experimental observations.

Macroseismic study of the Potenza (southern Italy), earthquake of 5 May 1990

The aim of this paper is to define the macroseismic field of the 5 May 1990 Potenza earthquake, analysing about 3000 questionnaire forms together with the results of the direct inquiries carried out in the field. The study evidences the seismic vulnerability of the Potenza district and of the whole of southern Italy in general, due to the low resistance characteristics of the old constructions and a lack of seismic prevention. Besides, geomorphological failure increases hazardous situations at the earthquakes occurrence. This earthquake provided a good test for checking and improving the ING macroseismic data collection procedures.

The 3 June 1994 Java Tsunami: A Post-Event Survey of the Coastal Effects

The paper is a report of the field campaign undertaken by an international team (Italian, French and Indonesian) a few weeks after the occurrence of a tsunami invading the south-eastern coast of Java (Indonesia) and it complements the results of a concurrent field survey by Asian and USA researchers. The tsunamigenic earthquake occurred on 3 of June 1994 in the Indian Ocean about 200 km south of Java. The tsunami caused severe damage and claimed many victims in some coastal villages. The main purpose of the survey was to measure the inundation and the runup values as well as to ascertain the possible morphological changes caused by the wave attacks. Attention was particularly focussed on the most affected districts, that is Lumajang, Jember and Banyuwangi in Java, although also the districts of Negera, Tebanan and Denpasar in Bali were examined. The most severe damage was observed in the Banyuwangi district, where the villages of Rajekwesi, Pancer and Lampon were almost completely levelled by the violent waves. Most places were hit by three significant waves with documented wave height often exceeding 5 m. The maximum runup value (9.50 m) was measured at Rajekwesi, where also the most impressive erosion phenomena could be found. In contrast, only in one place of the neighbouring island of Bali was there a slight tsunami, the rest of the island being practically unaffected.

Macroseismic evidence and site effects for the Lunigiana (Italy) 1995 Earthquake

On October 10, 1995, an ML= 4.8 (ING) earthquake occurred in the region of Lunigiana (northwestern Italy). The shock was felt over a large area and produced significant damage. We performed a macroseismic survey and damage zonation and assessed a maximum intensity VII MCS in the epicentral area. The damage pattern, that we investigated in detail for some of the villages in the most heavily damaged area, emphasises the role of surface geology in amplifying the effects. Topographic effects and near-surface geology are largely responsible for broadening the damage area. Given the moderate size of the earthquake, many of the macroseismic observations, including rotations of objects and the propagation of visible waves in the ground, are suggestive of amplification phenomena.

Numerical Simulations of the 1627 Gargano Tsunami (Southern Italy) to Locate the Earthquake Source

The historical tsunami that occurred on July 30, 1627 in Gargano (Apulia, Southern Italy) was generated by a very large earthquake (I=XI MCS scale) that produced severe damage in the whole promontory. In spite of the large number of macroseismic observations, it is not possible to determine the epicenter and the generative fault position unambiguously. Though the historical sources concerning the tsunami are not extremely detailed, yet they allow us to locate and to evaluate the most important wave effects on the coasts. A prior tsunami study, conducted by performing numerical simulations based on integrating shallow-water equations via a finite-element technique, assumed a genetic dip-slip focal mechanism on faults that were temptingly placed in different positions both on land and offshore (Tinti and Piatanesi, 1996). The present work, which represents a natural continuation of that investigation, aims mostly at constraining the location of the tsunamigenic fault on physical grounds; this is accomplished by means of tsunami simulations on a new finer finite-element grid and by using the earthquake sources described in the previous paper as well as new inland faults striking N-S. It is shown that mesh refinement leads to better solutions, especially as far as the computation of the maximum elevation along the coast is concerned. Determining the position of the causative fault was one of the main motivations of this research. It has been found that compatibility with the available tsunami data requires that the fault be located inland in the coastal area embracing the Lesina Lake and the mouth of the Fortore River: the strike, however, is not too well constrained, though E-W striking seems preferable to N-S.

Coastal Effects and Damage Due to the 3rd June, 1994 Java Tsunami

A tsunamigenic earthquake occurred on June 3, 1994 with a violent tsunami involving the south-eastern Java coasts (Indonesia). The results of the report of the field campaign undertaken by an international team (Italian, French and Indonesian) during June 22 to June 28, a few weeks after the tsunami occurrence, are described in this paper, integrating the data obtained by a concurrent survey carried out by Asian and USA researchers. During the survey the authors focused their attention on the most affected districts in Java and Bali islands, visiting many coastal villages in order to interview inhabitants, to analyze damage, and to measure tsunami heights and inundation. It was underlined that the earthquake occurred during the night and caused no damage, being felt only by a few people. About 30–40 minutes after the shock generally three waves attacked the coast with documented heights often exceeding 5 meters, causing the destruction of some villages and claiming more than 250 victims. In this paper the authors present the results of their investigations, describing in detail tsunami heights and inundation as well as destructive tsunami effects at coastal villages This paper complements a previous preliminary report on this disaster (Maramai and Tinti, 1996).

Updating and Revision of the European Tsunami Catalogue

The first catalogue of the European tsunamis was built in the frame of the EU Projects called GITEC, and GITEC-TWO. The catalogue was implemented as a FoxPro 2.5 database, and it can be fully used on PC with Windows 3.1 or with the first versions of Windows 95. In the present work, we describe the new version of the database that has been totally rebuilt within the Visual FoxPro 6.0 DBMS environment in order to make it suitable for the operating systems currently on the market (i.e. Windows 98, Windows 2000, Windows NT, etc.). The general structure of the previous data base version is preserved. The catalogue is accessible through a main screen containing a) functional buttons to perform the basic inquiry, and browser actions, and b) parametric, and textual data concerning a specific event that can be selected by the user. The data base has been enriched by including new tsunami entries, as the result of revision of historical sources, and by adding a new category of data, namely graphical data, such as digitised tide-gauge records, photos, relevant maps, etc., that form a special section accessible from the main screen. Moreover, the auxiliary data base of the references has been updated by introducing all the contributions, such as papers, and scientific studies that have been published in the last years.

Study for a pilot monitoring and alarm system for the Calabrian Sicilian tsunamis

Abstract In the frame of the EU GITEC-TWO Project (Genesis and Impact of Tsunamis on the European Coasts: Tsunami Warning and Observations) one of the main goals is the development and installation of a pilot Tsunami Warning System (TWS) station in Italy. The Ionian Sea region watering the eastern coast of Sicily (southern Italy) experienced large tsunamis in the past and has been identified and selected for the Italian TWS station installation. Most of the existing examples of TWS already available around the world are appropriate for tsunamis that are produced by earthquakes with source areas located tens or hundreds kilometers offshore, but they are not efficient for local tsunamigenic earthquakes. However, in the Mediterranean region most tsunamis are generated very locally and waves attack the coast at most within 5–10 minutes after the shock. Consequently, our system is conceived for those coastlines potentially affected by tsunamis generated by coastal earthquakes and is designed for an immediate detection and an early warning.

The Double Landslide‐Induced Tsunami

The 2002 crisis of Stromboli culminated on December 30 in a series of mass failures detached from the Sciara del Fuoco, with two main landslides, one submarine followed about 7 min later by a second subaerial. These landslides caused two distinct tsunamis that were seen by most people in the island as a unique event. The double tsunami was strongly damaging, destroying several houses in the waterfront at Ficogrande, Punta Lena, and Scari localities in the northeastern coast of Stromboli. The waves affected also Panarea and were observed in the northern Sicily coast and even in Campania, but with minor effects. There are no direct instrumental records of these tsunamis. What we know resides on (1) observations and quantification of the impact of the waves on the coast, collected in a number of postevent field surveys; (2) interviews of eyewitnesses and a collection of tsunami images (photos and videos) taken by observers; and (3) on results of numerical simulations. In this paper, we propose a critical reconstruction of the events where all the available pieces of information are recomposed to form a coherent and consistent mosaic.