Crustal anisotropy, Moho and Conrad depths, and topography of the 410 and 660 km discontinuities Malaysia, Myanmar, and Thailand revealed by P-wave receiver functions and common conversion point stacking

This study utilizes advanced seismic methods to investigate the complex geodynamic processes beneath the West Burma, Shan-Thai, Indo-China terranes, and the Gulf regions of Southeast Asia. Through the comprehensive analysis of teleseismic waveforms from 25 seismic stations across Malaysia, Myanmar, and Thailand, crustal anisotropy and the depths of the Conrad and Moho discontinuities are investigated, while also mapping the topography of the mantle transition zone (MTZ) discontinuities at 410 and 660 km. Utilizing H-K stacking and Common Conversion Point (CCP) stacking, this study provides detailed estimations of crustal thickness (H) and Vp/Vs ratios (k), highlighting significant crustal thickening in the West Burma Terrane consistent with subduction processes beneath the Sunda megathrust. The gradual increase in Moho depth within the Shan-Thai Terrane towards the Indo-China Terrane boundary, alongside Conrad discontinuity variations, underscores its complex tectonic evolution. In contrast, the Indo-China Terrane exhibits pronounced crustal thickening, reflective of its intricate collisional history. Additionally, observations in the Gulf regions indicate shallower crustal thickness and evidence of mantle upwelling, with implications for seismic risk assessment and geodynamic modeling in Southeast Asia.