La « discontinuità 20° »
In reference to some circumstances ascertained in a<br />recent study of the seismic novement that occurred in Sicily on the 23rd<br />December 1959, two a t t e m p t s have been carried out in order to determine<br />the depth of the discontinuity surface...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
1966-06-01
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| Series: | Annals of Geophysics |
| Online Access: | http://www.annalsofgeophysics.eu/index.php/annals/article/view/5042 |
| Summary: | In reference to some circumstances ascertained in a<br />recent study of the seismic novement that occurred in Sicily on the 23rd<br />December 1959, two a t t e m p t s have been carried out in order to determine<br />the depth of the discontinuity surface t h a t we suppose to be the cause of<br />anomalous behaviour observed in t h e travel-time curve of P-waves near 20&deg;<br />I n the first part some possible q u a n t i t a t i v e consequences deriving from<br />t h e observed disagreement with Jeffreys-Bullen travel-time curves have been<br />characterized, on the assumption that the velocity of P-waves resumes<br />ordinary behaviour just below the Moliorovicic discontinuity. On this<br />assumption, a probable velocity law has been determined t h a t presents a<br />remarkable discontinuity at a depth of 586 km.<br />I n the second part it has been demonstrated t h a t , assuming the numerical<br />values of velocity proposed by Gutenberg in the range 40 &lt;= h &lt;= 80 kin, the deduced equations of the two branches of P-waves travel-time<br />curve give a distribution of velocity values as function of depth t h a t presents<br />a marked discontinuity at the depth of 536 km, immediately followed<br />by a marked increase in the rate of increase of velocity with increase of<br />depth. |
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| ISSN: | 1593-5213 2037-416X |