Travel time analysis of P waves arising from six underground nuclear explosion at Novaya Zemlya

• Published in: Annals of Geophysics
• Main Authors: B. FEDERICO, A. BOTTARI
• Format: Article in Journal/Newspaper
• Language: English
• Published: Istituto Nazionale di Geofisica e Vulcanologia (INGV) 1977
• Subjects: Meteorology. Climatology; QC851-999; Geophysics. Cosmic physics; QC801-809; Fennoscandia; Novaya Zemlya
• Online Access: https://doi.org/10.4401/ag-4815; https://doaj.org/article/9381a24cf84a4a5a808e0c9a1c79c199

SUMMARY. - The analysis of the travel times of the P waves generated by six underground nuclear explosions in Novaya Zemlya shows notable early arrivals (oo4sec) at the Fennoscandia stations. These observations, together with a marked linear dependence of the travel times on the epicentral distance throughout the interval 8.5 < / J ° < 20.4. were evaluated with the aim of producing a satisfactory model for the upper mantle of the Baltic zone. In particular, there appears a considerable mantle zone with almost uniform velocity, or at least, with not of increasing velocity. This mantle zone is delimited above by a discontinuity at the 86 km depth (v = 8.45 km/sec), and delimited below by the «20° discontinuity» (h = 507 km; v = 10.56 km/sec). The proposed model is amply verified on the basis of the foreseen travel times compared with the corresponding ones, observed from a fair number of impulses associated with teleseismic Pn, noticeable as far as 40°, and from phases reflected and refracted on the discontinuity at 507 km.