INDEPTH WIDE-ANGLE REFLECTION OBSERVATION OF P-WAVE-TO-S-WAVE CONVERSION FROM CRUSTAL BRIGHT SPOTS IN TIBET

Three-component wide-angle seismic data acquired in southern Tibet dur ing Project INDEPTH show strong P-to-S converted reflections from refl ectors that area aligned at a depth of similar to 15 kilometers beneat h the northern Yadong-Gulu rift, These converted reflections are local ly higher in amplitude than the corresponding P-wave reflections; Mode ling of reflection mode conversion as-a function of incidence angle in dicates that this condition obtains for a reflector that is a solid ov er fluid interface; it is not typical of a solid-solid interface, The likely candidates for a fluid trapped within the crystalline crust of southern Tibet are granitic magma and water (brine).