In the mid-sixties of the 20^th century, a seismicity one-dimensional
model, based on a spring system with friction, was presented by the
two authors mentioned in the title. Through this model was studied the
viscosity behaviour involved in the stratums mutual displacement.
However, in the analysis pertinent to the occasion, seeing the fig.13
ibid it can be observed an error related to the viscosity function (low
speeds’) limits, which determines its “performance” during the time -
lapse of the stratums breaking. From the height of the present knowledge, using the
Elementary Catastrophes Theory developed in later times by René Thom
and Zeeman, we have reached certain conclusions which, although do
not refute the results of said article, they can significantly improve some aspects of
the model and in general of the earthquakes physics.