Main Article Content
already carried out on the earthquakes occurred in Western Sicily.
The hypocentral data investigation concerning a further large earthquake
of the swarm, has confirmed an hypocentral depth close to the
"Molio". Grouping conveniently the investigated earthquakes it was possible
to calculate the longitudinal waves travel-times curves at the following
depths: 30, 35, 40, 45, 50, 00 km (A < 20°). Some interesting results concerning
the first impulses of P„ waves have been found (existence of two
series of waves, P,n and IJ„2 having a slightly different velocity). Five curves
for each examined h have been calculated; the P„ (the general) using all
the onsets including the ones whose residuals resulted later to be about
three seconds: the Pni and the P„2 representing a Pn subdivision obtained
by reducing the residuals range: the P„ -^13° and the P„ (10°M 20°) for
2» < A < 13° and 10° < A < 20° respectively calculated. (The P„ 13°
approaches to a straight line, in accordance with other estimations for curves
investigated along shorter paths). The paper contains also all numerical
tables related to 29 travel-times curves calculated every 20 km; as well
as the curve corresponding to li = 17.5 km. The last curve has been obtained
averaging the values of depth from 5 km to 30 km in order to fill
the gap 0 i—i 30 km.
No Permission Required
Istituto Nazionale di Geofisica e Vulcanologia applies the Creative Commons Attribution License (CCAL) to all works we publish.
Under the CCAL, authors retain ownership of the copyright for their article, but authors allow anyone to download, reuse, reprint, modify, distribute, so long as the original authors and source are cited. No permission is required from the authors or the publishers.