Crustal structure beneath the Indochina peninsula from teleseismic receiver functions

Abstract

We analyze teleseismic receiver functions to determine the crustal structure beneath the Indochina peninsula which is located immediately south‐east of the eastern Himalayan syntaxis basin. We found that the Indochina peninsula is characterized by a thin (∼31 km) crust with a low Vp/Vs ratio (∼1.68). The intra‐lower crustal low‐velocity zone (LVZ) is observed beneath the northwestern part of our study region. We hypothesize that it is an extension of the lower crustal LVZ observed beneath the southeastern Tibet and the South China block and that it terminates at the Dien Bien Phu Fault (DBPF). A LVZ observed in the upper crust beneath southeast of the DBPF indicates that the crust is ductile and earthquakes are rare.