Ancora sui tempi di tragitto delle Pn provenienti dalla Sicilia Tabelle numeriche per varie profondità ipocentrali
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Abstract
This paper follows the foregoing studies by the A.A.
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.
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.
Article Details
How to Cite
1.
MARCELLI L, PANNOCCHIA G. Ancora sui tempi di tragitto delle Pn provenienti dalla Sicilia Tabelle numeriche per varie profondità ipocentrali. Ann. Geophys. [Internet]. 1974Nov.25 [cited 2023Dec.9];27(1-2):221-34. Available from: https://www.annalsofgeophysics.eu/index.php/annals/article/view/4921
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