Designing Virtual Social Memory Organizers: Online and Offline Perspectives for Historical Earthquake Data Organization and Dissemination

G. Rubbia Rinaldi
P. Albini
Istituto di Ricerca sul Rischio Sismico (IRRS)
National Research Council, Milan, Italy

M. Padula
Istituto per le Tecnologie Informatiche Multimediali (ITIM)
National Research Council, Milan, Italy

1. Introduction

This paper looks at the changes the information revolution has produced in the organization of memory. The role of mass storage, created as working memories (disorderly deposits of information) has, in fact, been modified. Today this storage tends to emulate those containers of society's memory--such as libraries, museums, collections of newspapers and journals, encyclopedias--and even, in some cases, to replace them or, more frequently, to become the integrated instruments without which they cannot function. The electronic memory is itself being replaced by the information network with all the information and computing resources, distributed and concentrated, that this offers, and in which everyone intervenes with his own contribution, altering, updating, and offering his own products.

After an introductory fresco of the Global Information Society, we present the motivation for rendering a Social Memory Organizer (SMO) virtual and global on the network. We then discuss the design of a Virtual Social Memory Organizer (VSMO), taking as our example the case of historical earthquake records for seismic hazard assessment.

Today seismic hazard assessment investigators want to have access to all the available information on seismic events in its entirety, not limited to the condensed version recorded in parametric earthquake catalogues. This information--such as historical records and their original texts, intensity maps, and so on--is in fact "often extensive but is generally lost to a numeric catalogue user and, often, also to the compiler himself." For this reason, parametric catalogues "are losing their official authority. Seismologists and engineers increasingly look upon them as starting points rather than as final issues and demand the availability of the complete information set" [1].

Finally, a solution appears through the exploitation of a CD-ROM and of an Internet Web for offering this basic information, allowing those interested to retrace the compilers' steps in producing the parametric earthquake catalogues and evaluate procedures by accessing historical earthquake records directly. The CD-ROM and the Web become the two faces (offline and online, respectively) of a medium dedicated to keeping a country's memory by recording and making available all the information useful to the assessment of seismic hazard.

The scientific proposal is the product of a collaboration between seismologists and historians of the Istituto di Ricerca sul Rischio Sismico (IRRS) and computer scientists of the Istituto per le Tecnologie Informatiche Multimediali (ITIM) of the National Research Council (CNR) of Milan, Italy, within the framework of an Italian project for the evaluation of seismicity (Gruppo Nazionale per la Difesa dai Terremoti, or National Group for Protection against Earthquakes [GNDT]) and of the European project "A Basic European Earthquake Catalogue and a Database for the Evaluation of Long-Term Seismicity and Seismic Hazard" (BEECD).

2. Evolutionary phases in the Global Information Society

In the Global Information Society the role that is, or should be, played by the institutions involved in the organization and distribution of the social memory (libraries; museums; publishers of newspapers, other periodicals, and books; television; film collections) assumes enormous interest.

The evolution of the new information technologies has followed a sequence that may be roughly summarized in five steps:

  1. Heterogeneous signals, representing different documents (images, texts, sounds) are converted into numeric form. This means, on the one hand, that a greater number of data that are heterogeneous but rendered compatible by digitalization can be transferred on the same channel, while on the other, models of data are defined (structures of their organization and of the operations for their manipulation and retrieval) as the formalization of the structure of various types of real documents and of the procedures for handling them. On the basis of the models defined, systems are developed and used for the automatic management of the containers of social memory that are archives of forms, warehouses, and administrative archives; archives of narrative texts, such as libraries, collections of newspapers, and encyclopedias; art galleries and photographic collections. Everything can be digitized, at least in its visual form; even museums, which organize objects (that is, material artifacts), find a digital form in image databanks. Mass-produced electronic memories, created as working memories (disorderly deposits of information), tend in evolving to emulate containers of social memory and even, in some cases, to replace them or to become instruments without which they cannot function, integrated with them.
  2. The increasing density of the networks and the creation of information highways have caused an increase in information points and in transmission channels, permitting a dramatic increase in the number of messages transferred.
  3. Multimedia and hypermedia systems answer the demand for more compact supports, powerful and rapid in accessing and transmission, and provide for the organization of information according to models appropriate to their conceptual use. They also allow the reunification of all the forms and representations of information formerly separated by the technologies available for telephone communication, television, and personal computing.
  4. The study and development of methodologies of interaction between human beings, and between men and machines (cooperative design, diagrammatic languages, user navigation assistance) have helped tailor communication to the work to be done and the messages to be sent.
  5. The synergy of all these technologies has produced environments that go beyond adaptation to user needs: the electronic memory is replaced by the information network with all its resources of information and computation, distributed and concentrated, to which everyone can contribute his own modifications and updating and offer his own products. This produces dramatic innovations; perhaps the most macroscopic aspect is the development of the Internet with the environment of the World Wide Web, which has grown to close to 50 million connections in a very short time.

3. The Social Memory Organizer

A substantial part of the history of a country can be reconstructed from the historical/social memory organized by three institutions (Table 1): libraries, museums, and administrative/research institutions. Each of these institutions is a specialization of what we shall call Social Memory Organizer (SMO) and is dedicated to the conservation of something for some reason.

Table 1. Specialization of the Social Memory Organizer

Institution                Object of conservation        Aspect of interest
Archives and libraries     Written sources,              Describing, recording
  museums                    iconographic sources and      showing
Administrative/research    Heterogeneous/multimedia      Interpreting
  institutions               sources    

The Global Information Society modifies the configuration of the SMO and the scenario in which its specialization exists. We focus here on the performance of the new information technologies that will, hopefully, be applied to the preservation and fruition of our various cultures and traditions.

In the Global Information Society, the individual specialization of the SMO is no longer characterized by the building it occupies; the place in which it is located and the way to get there are of no importance when accessing its information. This information is now traced by virtual navigation in an information space through sites of networks that, while they occupy space and have a physical location where the machines, exchanges, and cables are installed, are invisible and irrelevant for the user. Access to and recovery of stored material requires traveling or moving material only in a virtual sense; the idea of travel does remain in some cases, but as a metaphor of interaction with the user. The sense of movement is also reversed: now it is the data that move toward the user and not vice versa [2].

The boundaries of the specialized SMOs vanish in the similarities of the functions they perform; they are no longer separated by the type of product they offer users [3]. We speak of global library and global museum, referring to the virtual versions of these institutions that ally with the other institutions performing analogous functions, extending themselves continuously through these analogies (Figure 1).

Figure 1. Each virtual SMO extends its functions toward other connected virtual SMOs. From each point of view the SMO becomes a global museum or a global library or a global institution.

The loss of physicality increases the volume of information that can be made available, increases it beyond the control and influence of the SMO itself. The virtual global SMO extends through all the sites of the network relevant for its functions and the subjects treated, and all the sites share responsibility for the evolution of the virtual global SMO, for the volume of information available, its updating, and the services offered. The need, as a consequence, for cooperative working methodologies [4,5] and suitable instrumentation is obvious.

The SMO's use of the new technologies is historically distinguished, depending on the kind of objects they conserve and their institutional interest.

Libraries are naturally more oriented to computer science technologies: the concept of information retrieval is native to librarians' traditional modes of searching, so they are keener on offering their wealth of information online through networks. The inevitable adoption of the new technologies leads to dramatic organizational, social, and commercial innovations [6,7].

Museums in their virtual version enhance the success of real museums in the conservation of their collections and in the improvement of visit frequency but also in culture communication and dissemination [8,9].

Administrative research institutions perform activities that are information intensive in the sense of Levy and Marshall [6]. They collect documentation, synthesize it, annotate, customize and transform it into archives whose contents are very far from the originating sources.

What we propose and analyze here is an SMO of the third type, that is, a Virtual SMO (VSMO) to support a research institution involved in projects devoted to the assessment of seismic hazard.

4. A Virtual Social Memory Organizer for historical earthquake records

A description of historical earthquake records and of their peculiarities with respect to their organization in a VSMO is supplied in section 4.1; the perspectives, offline and online, of the dedicated VSMO are described in sections 4.2 and 4.3, respectively.

4.1 Historical earthquake records

"The numerical earthquake catalogue has indeed proved to be a powerful instrument for evaluating the seismicity and seismic hazard of an area. But its effectiveness, that is, a format which allows much information to be condensed in a relatively small amount of memory, also represents its limitation, since it does not take into account all information which is available as background to the catalogue itself" [1].

A parametric earthquake catalogue is an ordered set of parametric strings. Each record contains the main parameters of a seismic event, such as date, epicenter coordinates, intensity, and magnitude of the earthquake. It is derived from a heterogeneous set of information, which is currently defined as "historical earthquake records." Historical seismology studies of the past 20 years (for an introductory list of references see [10]) aimed at rendering clear and effective the procedures behind the compilation of a parametric earthquake catalogue, with special attention paid to making available to users the whole set of information used by the catalogue compilers. The joint proposal presented here mainly focuses on the first two levels of investigation of an earthquake, according to the most recent methodological development of historical seismology [11].

The first step of research consists of the identification and retrieval of historical sources dealing with the earthquake in study or with earthquakes in a certain time span. An earthquake lasts for some seconds and leaves traces of its occurrence in an area the dimensions of which depend on the size of the earthquake itself. The territory and places where the memory of an earthquake survived can be different and at least identified as:

Figure 2 shows the results of a study on Venetian documents on the late 17th century stored at the State Archives of Venice [12]. The record for the 4 December 1690 earthquake describes damage in the locality of Chiusa (Friuli), while the record for the 22 December earthquake reports damage and casualties in the locality of Ancona (Marche).

Figure 2. Date and archival location of Venetian documents on the earthquakes of 4 and 22 December 1690 (left) and localities in which earthquake effects are reported (right).

A single record is not sufficient for a correct seismological interpretation of an earthquake. With reference to the December 4 earthquake, historical sources describing the effects in about 100 localities in Austria, Germany, and Italy can be found, apart from the State Archives of Venice, in some local libraries in Austria, in the National Library of Vienna, and in the Secret Vatican Archives in Rome [13,14,15].

Therefore, records of this earthquake are physically scattered in a number of libraries and archives throughout Europe. The first link to be kept is that between the earthquake record and the archive/library that stores it. This is important for at least two reasons: (1) to make the information available to other researchers, to avoid duplication of research; and (2) to know the context of the record, to be able to perform a correct historical interpretation of the information it supplies.

Each historical earthquake record should contain, as minimum information,

  1. The time of occurrence
  2. The locality affected by the earthquake
  3. The effects in the mentioned locality

Each earthquake is "built up" by collecting a number of records concerning a number of localities; these records are strictly linked together by the time of occurrence. Problems can arise because different calendars are in use or have been adopted over the centuries; therefore, each record has to be carefully interpreted with respect to reported time.

Problems may arise regarding the place name to which an earthquake record refers: It may be written differently in different languages or may have been altered; there could be more than one place bearing the same name in a small area; or the same name may be given to a place that was abandoned and then reconstructed elsewhere. It is necessary to interpret the sources with respect to this aspect and to keep track of the final decision for future checks. Place names and coordinates must be referred to an authority that consists of a directory in which place names are related to coordinates. The directory should be organized in such a way that all denominations that have been recognized as pointing to the same physical locality point to the same coordinates and are considered as one unit only.

The main relationships to be established are therefore:

4.2 An offline perspective: Designing a CD-ROM

The offline perspective of a Virtual Social Memory Organizer for historical earthquake data concerning an area can be defined through the characteristics of the medium that stores the data: the CD-ROM.

Once edited, the CD-ROM freezes the data and their interpretation at a given state of the art (investigation); it requires a player that is often is sold with the personal computer, its offline reading probably being more accessible than Net access for a subset of users.

It will be a medium dedicated to keeping a country's memory by recording and making available all the information useful to the assessment of seismic hazard of that country. It will contain historical earthquake data (historical sources and their interpretations) that will allow those interested to retrace the compilers' steps in producing the parametric earthquake catalogues and evaluate procedures by directly accessing historical earthquake records.

Facing the problem of developing tools for consulting these data, the following design phases have been defined:

  1. Analysis of user's needs. Characterization of the needs of future users of the CD-ROM (historians, seismologists, engineers), which can be expected to include the definition of data of interest and the modes of consulting them (search and navigation through the databases of historical earthquake records). A typical need will be, for instance, to retrieve all the events that affected a locality over a certain time span, and, for each event, the information that historians searched, examined, and compared to build up the event.
  2. State-of-the-art analysis. Investigation of projects for organizing documents on earthquakes on nontraditional supports. CD-ROMs are used to store instrumental data by data centers at geophysical institutes, for example, that distribute them on request, but what about historical earthquake data? A recent example for Italy is the Catalogue of Strong Earthquakes in Italy, designed by the Italian National Institute of Geophysics, which offers the synthetic information contained in the traditional catalogues plus structured comments on the earthquakes (e.g., state of earthquake review, major earthquake effects) and the original texts used for the study of the earthquakes [16]. Users logically move through descriptions of earthquakes, felt localities, comments, and references, while data are stored in different archives organized in a hierarchical database.
  3. Data (content) analysis. Characterization with respect to the significance of data, interrelations, and the type of support--textual data (historical sources and bibliographies) or pictorial (iconographic sources, maps) being, in fact, sources of a different nature, such as catalogues, studies, printed chronicles, travelers' reports, newspapers, and sometimes also including architecture, iconography, and epigraphs [17].
  4. Structural design. Design of the navigation structure in the CD-ROM, that is, translation of the users' needs previously identified into functional specifications for the product, i.e., data organization and structuring contents and paths. The design process will benefit from the use of a data-modeling methodology. See, for example, the Isakowitz et al. [18] focus on the design, development, and construction phases.
  5. Presentation design and user interface design. How to present information elements to users and how users interact with them. This phase will include decisions about the adoption of a user-friendly style of interaction versus a user-oriented one. For instance, a family tree, which graphically synthesizes the relationships among sources, is a typical example of the use of diagrams; it is worthwhile considering it as a clue for visual access to historical earthquake records.
  6. Software/hardware analysis. Analysis and choice of the platform for development, with particular attention for what existing software can provide in the way of (a) handling the data (DataBase Management System) and their geographic location (Geographic Information System); (b) indexing and retrieval of text and images (Information Retrieval Systems); (c) consultation by association (Hypermedia Systems); and (d) compatibility and portability. Postpischl et al. [1] underlined that the need to navigate through historical earthquake data "as easily as possible suggests the use of a database relying on hypertext philosophy by linking together the elementary pieces of information for the historical research." There is also a need to create software to integrate the systems mentioned above, in order to guarantee uniform access to and utilization of data that are heterogeneous and complex.
  7. Sample dataset selection. Identification of a sample of data that is meaningful for the whole database of interest for the project, with which to construct the pre-prototype.
  8. Data standardization. Verification of the congruence of the sample data and their availability as formatted.

On the basis of the requirements detected in the design phases, development will involve (1) pre-prototype production on magnetic support, including the sample dataset; (2) testing to verify prototype usability and data consistency; (3) refinement after evaluation; and (4) extension to the whole dataset of interest.

4.3 An online perspective: Internet Web

In this context we mean to produce an information system that is flexible and integrated and can be used by workstations distributed over a telematic network, and that serves as a reference, constantly updated as studies and research proceed, for both researchers in the field of seismology and for common users for browsing selected documentation.

A large amount of documentation is as historical source; its digital conversion, organization, and integration are useful and necessary. We refer to hypermedia techniques for connecting the autonomous archives already existing on different net sites. When documentation is converted to a virtual form and offered on the Internet, the researcher's travel toward the information archives also becomes virtual.

Some parametric earthquake catalogues have already been organized in digital form and require a limited marginal cost to be interfaced to the Web. By connecting them to the historical earthquake records from which they originated, we proceed toward recording the procedures that have been used to derive their parameters. What we conceive for the future is a confederation of heterogeneous archives to relate the scattered pieces of information that are used during the compilation and reconstruction of an earthquake. Management systems will be chosen that are well known and already have or can be easily supplied with an interface to the Web. Archives of parametric data require a flexible and powerful system for data selection and logical operations [19]; for textual historical sources and bibliographic inventories, the CDS/ISIS system is adopted [20,21,22]. We believe that intellectual resources should focus on organizational aspects of the confederation and ignore, as far as possible, the details of implementation.

Groups of data, images, and texts retrieved from the archives must be assembled into complex entities of historical and seismological interest and their conceptual links set. We shall design and implement object-oriented data structures whose objects will be composed of data from archives of different types and also geographically distributed but reachable through the Internet; their methods will be the functions for data retrieval from the archives [23,24].

The design approach must lead toward the integration and packaging of the historical earthquake data, now refined and enriched by a consolidated experience of the domain specialists and of the heterogeneous historical sources from which they were derived. This requires that after design phases 1 and 2 similar to those planned from the offline perspective (as described in section 4.2) phase 3 follows for autonomous archive organizing. Phases 4 and 5 are highly multidisciplinary as they are for identifying and detailing the procedures to derive historical earthquake data, for data organizing infra-archives, for user interaction design.

With the information system we intend to circulate summarized information available in the databases, systematically collect and organize documentation found on the telematic networks, and solicit advice, ideas, and information about crucial problems and concepts. Consequently, we shall provide for

We see a perspective in a Web composed of different heterogeneous archives supplied with a global layer as a common access structure by entity of interest. The entities allow seismologists and historians to formulate their information needs in the usual language. The Web is integrated with services for testing and educating the people.

5. Acknowledgments

Thanks are due to Andrea Moroni for his help in drawing figures and to Max Stucchi for his valuable suggestions and support.

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