1. Goals
The main scope of the project "A Basic European Earthquake Catalogue
and a Database for the evaluation of long-term seismicity and seismic hazard"
(BEECD) was to establish and test a procedure for compiling and upgrading a
parametric earthquake catalogue of Europe and a database of primary data, to
serve both as a tool for understanding the long-term seismicity and as a
reliable input for seismic hazard evaluation.
By "European" it was meant the territories of the countries belonging to EC and neighbouring areas, West of 31° East. Actually, for the assessment of seismic hazard of Europe it is necessary to take into consideration also the seismic sources which lie outside EC and can affect its territory. Therefore, the project covered also areas which do not fall within EC frontiers but the earthquakes which originate there may significantly affect EC countries.
By "long-term" it was meant as far back as data allow. The data potential for the Middle Ages and before is not uniform throughout Europe: therefore, a comprehensive review of this time-window would have required heavy historical investigation, was likely to be extremely time consuming and to produce a badly incomplete set of data. The time-window of the XX century presents special problems due to the combination of macroseismic and instrumental data; as other research was in progress on this topic (e.g. GSHAP), only limited efforts have been devoted to it. Finally, the time-window 1400-1899 was adopted.
As the compilation of a complete European parametric earthquake catalogue (PEC) may involve the analysis of several tens of thousands of entries, which was far from the real possibilities, the project mostly concentrated on damaging earthquakes and, among them, on a basic set of strong earthquakes, essential for long-term seismicity and hazard assessment.
2. Results and deliverables
The main results and deliverables are:
3. How the results were achieved
3a - The qualified BEECD Working File
The BEECD Working File (WF) is a file where:
The input PEC to be used for compiling the WF were selected among those
published and carrying references. This means that partners agreed that BEECD
would adopt the most recent, published version of the input PEC, but not
necessarily the very last one, and that one goal of BEECD would also be to make
transparent the changes made to that version afterwards.
Parameters and format of the BEECD WF were determined by considering the format
of the input PEC, the GSHAP format and some special needs of BEECD. The adopted
size threshold was Io/Ix >= 4/5 or M >= 3.5; accordingly, BEECD WF
1400-1899 contains 13.209 entries; BEECD WF <1400
contains 655 entries; BEECD WF 1900-1963 contains
16465 entries.
Multiple determinations, that are entries from different PEC which refer
to the same event, providing coincident or conflicting set of parameters, were
identified in a preliminary way by experienced compilers and flagged by means
of ad-hoc codes.
The next step was to evaluate the data sets supporting each entry of the
WF. Supporting data sets (hereafter defined as roots) show a great
variety of type: they range from a few lines, compiled by someone with the aim
of summarising the earthquake knowledge, to papers or monographs reporting
comprehensive investigation on specific earthquakes. A root scale based on type
(earthquake studies with datapoints, without datapoints, etc.) and quality
(roots based on primary sources, primary sources and compilation, etc.),
consisting of 13 classes, was created, tested, upgraded and then applied to all
entries of the WF. The root classes were finally grouped into 3 levels, to
establish upgrading priorities.
3b & 3c - Available studies inventory and earthquake investigation
In the first phase of the project partners inventoried earthquakes studies
published in the last fifteen years and found out which ones of them provided
"new, available roots" of better quality than the roots supporting the
corresponding entries in the BEECD WF (more than 1000 roots).
After inventorying the new available roots, partners started
investigating earthquakes, the parameters of which rely on low quality roots
and, additionally, key-events for some areas, for which an improvement of the
present knowledge was considered necessary. The investigation was performed
according to two approaches:
More than 600 new roots have been produced in the frame of BEECD. Some tens out of them refer to previously unknown damaging earthquakes. They were reported according to a standard format, then asssigned a root class according to criteria discussed in Task 2, and filed as new entries in the BEECD WF.
3d - Fake quakes
Special attention was paid to the problem of the so called "fake
quakes", that are, earthquakes which were inserted in the catalogues on the
basis of uncareful conclusions which are afterwards proved false on the basis
of rigorous historical investigation.
It seemed opportune that the investigation concerning earthquakes which proves
an earthquake to be fake is reported in a similar way as for the other events
and that a root is filed in the BEECD WF in the same way as for the true
earthquakes. Such roots have been marked with Z ("zomby" entries).
About 150 Z studies have been inventoried or produced in the frame of
BEECD. To avoid that events proven as fake are simply cancelled from files
without leaving trace (and to avoid future re-apparition because someone might
considered them as forgotten), these 150 Z studies will form the core of a
"Z catalogue" which, by the way, needs to be expanded, with priority to
the period before 1400, where fake quakes are more frequent.
3e - The European Earthquake Root Archive
The root archive is composed by roots of varied type and quality. For
the next steps, and for allowing a uniform, transparent procedure to be
followed in the future, it is important that they are compiled according to
standard format; it is not strictly necessary that they are all resident in the
same place.
This apply strictly for roots of type 1 (studies with intensity datapoints),
for which some hints from the most advanced experiences have been proposed. A
set of about 20.000 intensity datapoints exist, in principle, for
the European earthquakes (time-window 1400-1899).
For the roots of type 2 and 3 (earthquake studies, finished or in progress), a
standard format has been proposed.
The situation of the data with reference to these criteria has been checked for
a set of 383 "strong" earthquakes, selected among the most
significant in varied European regions. As the earthquake size distribution is
really uneven in Europe, the selection was performed adopting varied Ix/Io and
M threshold in 4 sub-areas.
3f - A survey of the current procedures for earthquake parameters determination
 and some tests on recently proposed procedures
 Earthquake parameters are derived from the supporting datasets according
to varied procedures, which mostly depend on the personal choice of the
compiler. Moreover, even when the same procedure is used, coefficients are
often determined in varied ways. The analysis performed shows that in some
cases the parameters found in the input catalogues are really derived form the
procedures declared, while in some others they do not fully fit in.
 Recently some formalised procedures have been proposed, aiming to allow that
the same procedure, applied to the same dataset, gives the same result
independently from the person who performs the determination. However, these
procedures still need tests and, when adopted, need also some calibration
performed at regional scale. Two tests were performed on a limited dataset of
strong earthquakes.
3g - A procedure for implementing the dataset and the related earthquake
catalogue
 The upgrading of parametric catalogues was often performed simply
modifying entries of the file according to: new research output, changes of
parameterisation criteria, changes of compiler's mind, etc., often without
leaving any trace of the change itself.
 The procedure assessed by the project is simple and transparent: an entry of the catalogue can be changed if a root of better quality is available and/or if the existing root has to be parameterised according to new criteria. This
process must be recorded and made available for future upgradings.
 The procedure was tested for 383 "strong" earthquakes; it works
and it can be used from now on. It is important to stress that, following this
scheme, also the changes performed "unofficially" to the input PEC after their
publication might be traced back and fully explained.
3h - Towards the parametric European Catalogue of Damaging Earthquakes
(EuCaDE)
 The procedure was then applied to the whole set of damaging
earthquakes (Ix/Io >= 5/6 or M >= 4.0), starting from the time-window
1400-1499. Multiple determinations of the same event were sorted out, selecting
one out of each group of them by means of the root class; that is, in case of several multiple determinations the preference was given to the entry
carrying the best Rc.
 The determination of the new parameters was performed only for a few cases; it
can easily be completed as soon as a general agreement is found.
EuCaDE can be implemented in the time-windows before 1400 and after
1900. It is recommendable that at least the time-windows 1200-1399 and
1900-1963 are implemented with priority.
4. Dissemination
BEECD web site
Most of the material mentioned above is on the way of being made
available to public on the server "Emidius"
(http://emidius.irrs.mi.cnr.it/BEECD), which is run as a joint
venture between Istituto di Ricerca sul Rischio Sismico and Istituto per le
Tecnologie Informatiche Multimediali, CNR, Italy. The implementation of the
parametric European Catalogue of Damaging Earthquakes will be performed
in an interactive way, searching the consensus of the partners and of the
national compilers by means of this web site.
In the frame of the project also the two volumes which represent the output of
the previous, precursor EC project "Review of Historical Seismicity in Europe"
(RHISE) have been made available on the same server
(http://emidius.irrs.mi.cnr.it/RHISE).
Publication
As this report shows, the project achieved many results. However, as
BEECD was firstly devoted to evaluate and make available the existing material,
then to perform investigation aiming to fill "holes" of knowledge, in order to
avoid effort duplications, most results are not worth to be published on their
own but rather only in a more comprehensive frame.
Therefore, it has been planned to publish, as a joint output of BEECD and other
autonomous initiatives, the following items: