Open AccessP ‐ and S ‐wave reflectors in D″ beneath southeast Asia
Author(s) -
Chaloner Jeremy W.,
Thomas Christine,
Rietbrock Andreas
Publication year - 2009
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.2009.04328.x
Subject(s) - reflector (photography) , geology , seismology , reflection (computer programming) , slab , geophysics , optics , physics , light source , computer science , programming language
SUMMARY Earthquakes from the South Pacific region recorded at the Kyrgyz Seismic Network (KNET) and the GHENGIS network (both part of the Tien Shan Continental Dynamics study) have been analysed to search for evidence of reflections from the D″ region. The reflection points of this source–receiver combination are in a seismically fast area beneath Southeast Asia. Employing several array methods, we find evidence for reflections from a D″ reflector in both P and S waves. The reflector depth generally agrees for both wave types. There is some evidence for a second, deeper reflector in this region; migrating the data suggests a lower‐seismic reflector beneath the northeastern end of the study region. The waveforms of P and S waves imply that the upper reflector has a negative impedance contrast for P but a positive impedance contrast for S . Several possibilities are discussed for generating the observed reflector(s), with the post‐perovskite phase transition in combination with a cold slab being the preferred explanation.