Double beam analysis of anomalies in the core-mantle boundary region

Details Double beam analysis of anomalies in the core-mantle boundary region Double beam analysis of anomalies in the core-mantle boundary region

Jul 1993

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993georl..20.1475k&link_type=abstract

Geophysical Research Letters (ISSN 0094-8276), vol. 20, no. 14, p. 1475-1478.

Physics

29

Earth Core, Earth Mantle, Nuclear Explosions, Seismic Waves, P Waves, Tectonics, Waveforms

Scientific paper

Seismic P-waves from nuclear explosions at the Kazakhstan test site (KTS) in Eastern Kasakhstan, observed at the Yellowknife-array (YKA, Canada) are used to analyze the structure at the base of the mantle under Severnaya Zemlya (Arctic Sea). Eighteen events at the Degelen subsite and nine events at the Shagan River subsite of KTS are studied. The simple waveforms and well controlled source parameters of nuclear explosions allow the use of the events as source arrays in addition to the usual receiver array configuration. A new method (double-beamforming) integrating both concepts is presented. This method increases the resolution considerably. For the Degelen-YKA path one anomalous arrival (1.9 s before PcP, slowness between P and PcP slowness) is observed. Smaller anomalous arrivals are found 6.5 s (Degelen - YKA) and 8.1 s before PcP (Shagan River - YKA). These anomalous phases cannot be explained with standard Earth models. They are produced by reflections from an inhomogeneity in the lowermost mantle at (82.3 deg N, 107.5 deg E) under the area north of Severnaya Zemlya. The strong variations between the wavefields for the two source-receiver combinations indicate a heterogeneous structure in the lower mantle. The anomaly found here is located close to an anomaly in the lowermost mantle beneath the Nansen Basin.

Affiliated with

Also associated with

No associations

Rating

Double beam analysis of anomalies in the core-mantle boundary region does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Double beam analysis of anomalies in the core-mantle boundary region, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Double beam analysis of anomalies in the core-mantle boundary region will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1071086