Goals
The qualified WF compiled by means of Task 1 and Task 2
represents the situation "frozen" at the time of publication of each PEC.
The goal of Task 3 is to retrieve and - mostly - to improve
the supporting data sets; it will be achieved according to two categories
of earthquakes:
earthquakes for which new studies
have been published after the publication of the referring PEC |
3a - to retrieve and evaluate the available roots | |
earthquakes for which no roots
of acceptable level are available |
3b - to investigate some of them (according to priority criteria) for producing BEECD roots |
The new, available roots were produced by a number of authors or agencies and reported according to varied format. To make them comparable one to another, a short report was designed containing:
Some case histories are presented in App. E1.1 to E1.3.
BEECD roots
After inventorying the new, available roots, the main problem
was to decide which earthquakes were to be studied in the frame of BEECD.
In principle it would have been recommendable to start investigating
earthquakes with level III roots. However, as a comprehensive investigation
of all the European earthquakes was out of the scopes and possibilities
of BEECD, it was agreed to allow priority also to levels I and II, in order
to get a consistent amount of data ready within the time and resource limits
of the project.
Therefore, 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.
a) Standard investigation
For Italy, Albania, Greece, Germany, Catalonia, UK, Slovenia, Hungary,
Bulgaria, etc. a standard methodology was adopted for obtaining new, upgraded
roots. It consists of few steps here described:
b) Extensive research
For the earthquakes of the Balkan area, the knowledge of which is generally
of low level, it seemed more convenient to start a general investigation:
ICST, London, took care of it. The study area included former Yugoslavia,
Bulgaria, Albania, Northern Greece (north of 39°N), Turkey (west of
27° E), Romania south of 44° N. The retrieval of local information
has been carried out with temporary assistants in Sofia, Istanbul, Athens
and, after May 1996, with a full time assistant in London.
All published and a number of unpublished catalogues available at ICST
for the study area were collected, and events before 1850 have been traced
back to original sources. Most of these sources, about 500, have been retrieved
and read. The search in Ottoman archives in Istanbul confirmed that there
is relatively little information to be found in these repositories, and
retrieval work was discontinued late in 1996. Regarding Slavonic sources
in Sofia, Thessaloniki and London, again here there is a dearth of information
concerning earthquakes. For Northern Greece new sources from Athens, Thessaloniki
are adding a considerable number of new and little-known events, chiefly
for the 19th century, through press reports which are contributing additional
information for the whole region.
Todate, the research permitted to collect information on a number of
earthquakes of all sizes for the period before 1900 from original, contemporary
and near-contemporary sources. Also, 40 damaging earthquakes, not
recognised previously as such, have been identified and studied further.
For about 400 of these earthquakes a report was prepared.
App. D7 contains a description of the methodology adopted and
a sample of important earthquakes studied in the area.
Results
Altogether, 618 new, BEECD roots have been produced.
Investigation of type a) was carried out for about 197 earthquakes, distributed as follows:
Investigation of type b) was carried out for 419 earthquakes
in the Balkan area (ICST, London).
Conclusions
Summarising, the studies performed in the frame of Task 3 did retrieve or produce about 1653 new roots (App. F1). They were given a root class and filed in BEECD format becoming the new roots file (NRf): the parameter Ds (data set source) was given codes assessing type, origin country and source of the root (App. F2).
They include 165 roots concerning so-called "fake quakes",
that are, earthquakes inserted in the PEC on the basis of careless conclusions
which were afterwards proved false on the basis of rigorous historical
investigation. It seemed opportune that investigations concerning earthquakes
which proves an earthquake to be fake are reported in a similar way as
for the other events, with special reference to the explanation of the
causes of the distortion which lead the fake event to be inserted in the
catalogues (App. E3.1 to E.5).
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), the corresponding roots were filed
in the same way as for true earthquakes (App. F2) and given a code
beginning with Z (zombie entries) to the parameter Set
(source
entry type).
Finally, for the earthquakes for which no new better roots were retrieved
or produced, the root supporting the corresponding F entry in the
WF was retrieved.
A scheme for reporting a standard investigation producing a new root
Scope. New roots, either of the best type (type 1, studies with
intensity datapoints) or of type 2,
are worth to be supported by a report where the author summarises:
0. Title. It contains the date and identification of the area of maximum effects of the event, as resulting from the investigation.
1. State-of-the-art before the investigation. This section should give:
At this stage a new root can be obtained by interpreting the most relevant
records; the root class
can be evaluated. If the investigation will stop here, section 4 and
next can be prepared.
If the root level will score below the agreed threshold, further investigation
will be necessary.
In this case the report will include also section 3.
3. Basic + ad hoc investigation. This section will be dedicated to report the main steps of the investigation and its results. Two main types of investigation could be taken into account:
5. Suggestions for earthquake parameters determination. This
report is intended for describing the root; the parameter determination
should be another step of the process, preferably not performed earthquake
by earthquake. However, in this section the investigator may summarize
from his knowledge of data some warnings useful for this purposes.
6. References.