Studies of Near-Source and Near-Receiver Scattering and Low-Frequency Lg from East Kazakh and NTS Explosions.

摘要

This study consists of three sections: (1) Evidence for Rg-to-P Scattering in Teleseismic P-coda and Rg-to-S Scattering in Regional Lg of East Kazakh Explosions, (2) Generation of Low-frequency Lg from NTS Explosions, and (3) An Array Study of the Effects of Known Local Scatterer on Regional Phases. In Section A, analysis of teleseismic data from Degelen and Shagan River explosions recorded at NORSAR and EKA arrays suggests that the low-frequency P-code is dominated by near-source scattering of the explosion-generated Rg into P. Regional data from Shagan River explosions recorded at WMQ indicates that the low-frequency Lg is probably due to the scattering of explosion-generated Rg into S. In Section B, analysis of regional data from Yucca Flat and Pahute Mesa explosions suggests that Rg-to-S makes a significant contribution to the low-frequency Lg. Strong support for this comes from a comparison of data from closely spaced explosions. In Section C, f-k analysis of regional events recorded at NORESS provides evidence for scattered arrivals Pn-to-Rg, Pg-to-Rg, and Lg-to-Rg, originating from a known prominent scatterer in the region of Lake Mjosa.