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We investigate a previously unrecorded rock avalanche deposit (Yadong rock avalanche) that resulted from a major mountain slope failure on the northwest slopes of Mt Chomo Lhari in the Eastern Himalayas. We provide detailed mapping of the Yadong rock avalanche, and date the rock avalanche using Be-10 surface exposure dating. The 10Be exposure ages of six samples suggest that the Yadong rock avalanche occurred between 14.2 +/- 1.3-13.1 +/- 1.3 ka during the Bolling-Allered (BA) period. The climate was semi-arid during the BA period as it is today, which suggests that precipitation was unlikely the trigger for this rock avalanche. The relatively small paleo glaciers make glacial debuttressing trigger unlikely. Since the rock scar is situated above the lower permafrost limit, degradation of permafrost associated with deglaciation was also unlikely to be the trigger. Given the rock avalanche is located near the Yadong fault which is part of the active Yadong-Gulu rift, and the Yadong-Gulu rift has experienced great earthquakes on centennial to millennial timescales, we suggest that the most probable trigger for this rock avalanche was a seismic event associated with the Yadong fault. The result provides evidence for identifying a paleo seismic event occurred during 14.2 +/- 1.3-13.1 +/- 13 ka. These findings have important implications for understanding the mechanisms for driving rock avalanches and associated landscape evolution across the Himalayas, as well as for extending the limited scientifically documented records of major mass movements in the Eastern Himalayan region. (C) 2018 Elsevier B.V. All rights reserved.