An Unusual Near-Surface Geohazard in Nepal: A case study of Smoke Emission at Hupsekot, Nawalpur

Abstract

The emergence of smoke and localized ground heating at Hupsekot Rural Municipality, Nawalpur, Nepal, prompted a multidisciplinary preliminary investigation of a potentially hazardous near-surface process. The smoke-emitting zone occurs in fractured, locally altered carbonaceous shale associated with grey and purple shale and subordinate calcareous sandstone of the Post-Gondwana Surkhet Group. Field mapping, four community interviews, rock sampling, gas measurements, XRF, XRD, and spring-water analyses were used to characterize the event. Smoke escaped through multiple openings amid disturbed rock and scorched vegetation. Reported carbon monoxide readings were higher at three vents than approximately 1 m away, while low oxygen readings indicated possible localized atmospheric hazards; instrument units and conditions require verification. Water collected near the smoke zone had an in-situ pH of 2.5, and XRD reference matching indicates quartz as a principal crystalline phase and suggests pyrite in selected samples; XRF screening shows variable sulfur and iron with substantial inter-test inconsistencies. The evidence motivates a working hypothesis involving fracture-mediated oxygen and water access, possible sulfide oxidation, heat accumulation, and carbonaceous-material smouldering.