Ds (dataset source) is composed by 6 characters, divided in three blocks.

Characters 1 and 2 tell the type of the root:

=    type 1 (with intensity datapoints)

=    type 2 or 3

=    type 4 (parametric catalogue).

Characters 3 and 4 tell the country of origin of the root, according to the e-mail codes.

For BEECD roots the code is EU.

Characters 5 and 6 tell the source of the root.

In the cases of studies belonging to structured archives or databases, they were given

the following codes:

IN

=   British Geological Survey (Edinburgh)

=   Instituto Cartográfico de Catalunya (Barcelona)

=   CEA (Fontanay-aux-Roses)

=   University of Athens, Department of Geophysics (Athens)

=   GeoForschungZentrum (Potsdam)

=   Geophysical Institute (Sofia)

=   Gruppo Nazionale per la Difesa dai Terremoti (Italy)

=   Imperial College (London)

=   Istituto Nazionale di Geofisica/Storia Geofisica Ambiente (Roma, Bologna)

=   Instituto Geografico Nacional (Madrid)

=   Institute of Physics of the Earth, Russian Academy of Sciences (Moscow)

=   Istituto di Ricerca sul Rischio Sismico, CNR (Milano)

=   Schweizerische Erdbebendienst (Zürich)

=   Seismological Observatory, Geodetical and Geophysical Research (Budapest)

=   Seismological Survey of Slovenia (Ljubljana)

=   University of Thessaloniki, Geophysical Laboratory (Thessaloniki)

=   literature