We present a high-resolution Sn velocity image beneath the Indian shield and its adjoining regions by inverting 11,243 Sn arrivals. The average apparent Sn velocity is 4.60 km/s with a velocity perturbation of ±0.2 km/s. High velocities are found under some parts of the Indian cratons, the Tarim Basin, the North-west part of the Indian plate and the Bay of Bengal, whereas the Burmese arc, Hindu-Kush, Tibetan Plateau and eastern parts of the Indian shield are dominated by low Sn velocities. The uppermost mantle shear wave velocity beneath the Indian shield is hitherto not known. Our Sn image clearly shows the heterogeneous character of the Indian lithosphere. The cratonic blocks of Singhbhum, Bastar and Aravalli show low Sn. The intracratonic Cuddapah Basin and north of Southern Granulitic Province also exhibit higher uppermost mantle shear velocity. We also observe a localized high beneath the exotic Coorg microcontinent located in the south of the western Dharwar Craton. The intriguing feature is the central Indian highs, which we interpreted as the basaltic lava pillows concomitant to the Deccan volcanism. Along the Himalayan arc, we observe higher Sn velocity which supports the idea of subduction of the Indian lithosphere into the mantle. Interestingly, the uppermost mantle beneath the Bay of Bengal shows faster and slower Sn in the western and the eastern regions respectively implying their distinct compositions. The Sn velocity distribution is discussed in conjunction with the Pn tomography results obtained previously. Low-velocity anomaly is conspicuous all along the Andaman-Nicobar island arc.

我们通过反转 11,243 个 Sn 到达来呈现印度地盾及其相邻区域下方的高分辨率 Sn 速度图像。平均视 Sn 速度为 4.60 km/s，速度扰动为 ±0.2 km/s。在印度克拉通、塔里木盆地、印度板块西北部和孟加拉湾的某些部分发现了高速，而缅甸弧、兴都库什、青藏高原和印度地盾的东部则是以低 Sn 速度为主。迄今为止，印度地盾下方的最上层地幔横波速度尚不清楚。我们的 Sn 图像清楚地显示了印度岩石圈的异质特征。Singhbhum、Bastar 和 Aravalli 的克拉通块体显示出低 Sn。克拉通内的 Cuddapah 盆地和南粒岩省北部也表现出较高的上地幔剪切速度。我们还观察到位于达尔瓦克拉通西部南部的异国库格微大陆下方的局部高地。有趣的特征是印度中部的高地，我们将其解释为与德干火山活动相伴的玄武岩熔岩枕。沿着喜马拉雅弧，我们观察到更高的锡速度，这支持印度岩石圈俯冲到地幔中的想法。有趣的是，孟加拉湾下方的最上层地幔在西部和东部地区分别显示出更快和更慢的 Sn，这表明它们的成分不同。结合先前获得的 Pn 断层扫描结果讨论了 Sn 速度分布。