catalogo de terremotos para america del sur catalog of earthquakes ...

I 9
The criteria for tbe selection of events, for time of origin, epicentral
coordinates and depth were the fol.lowing:
a. Historical macroseisms: give preference to the information obtained
from local pubiications at the Lime of tile earthquake;
b. inst umentaY .r tlhquakes from .international sources: select from the
different parsn~et ers those whicl have a better quality factor and the
m10ost adequat e r 'mpI T"p l /1onta cv in f: i- i on
V. 1NI'RES instrumuta:il earthquakes: By comparing with the values from
other sources, cmplete the information for the event
Concercning the maximum intensity, tie maximum value given in the cata-
Iogue of intensities is iven, for the same event.
For information on magnitude, the rcelationship between local magnitude
and the duration of the record was kept in mind, using coefficients deter­
oned For the regiton.
"ina1lly , the FlCinn- iEngdah] code for the region was included for every
entry in the catalog; this resulted of great utility for the selection of
events by regions.
'2. Determination of Intensity and P'rocedure Used:
Olne ,of the principal problems present in the evaluation of the seismic
intensity was due, fundamentall.y, to the differences in the quality of the
e:-iscing constructions before the occurrence of each one of the destructive
eartiluakes. It mu ;t he kept in mind that tile analys s covers an interval
of L f 20 or mre 'ears and, furthermore, that in some cases there
are
notable differences in the constructions, during the same epoch, for different
parL of tlie country.
For the reasons, for most of the historical earthquakes ;nnalved, the
adobe constructios was taken as the main reference, to estimate tile seismic
intensity. This type of construction is quite uniform throughout the Argentine
territory, existing since the very beginning of colonial times, specialiy
in the western region which is the one most affected by earthquakes.
For all of the cases studied, the estimate of intensity was global
isolated cases were not taken into account, since recent seismic events which
have been very well studied, such as that on 23 november 1977, have shown
that apparently very high intensities are due, generally, to very special
local effects or specific design problems.
PILANS FOR FUTURL UP )ATING
The hypocenter catalog is kept up to date with INPRES final determinaions
but it is foreseen that there will be revisions, once each semester,
by comparing such data with that received from international centers.
Concerning the catalog of intensities, this will be kept up to date