关键词: 腾冲黑空山火山, DEM模型可视化, 火山地貌, 熔岩流单元

Abstract:

A digital elevation model(DEM)is a digital representation of terrain surface morphological attributes, describing ground relief with spatial position and terrain characteristics. With advancements in technology, particularly increased satellite data acquisition capabilities, accurate high-resolution DEMs have become crucial in volcanology research, especially in remote regions. The Tengchong volcanic field, one of China’s prominent young volcanic groups, has experienced Cenozoic volcanic activity from the Pliocene to the Holocene. Recent monitoring and studies indicate that three Holocene volcanoes—Heikongshan, Dayingshan, and Maanshan—pose potential future eruption risks. The volcanic activity of these three Holocene volcanoes has garnered significant attention. This paper focuses on the Heikongshan volcano in the Tengchong volcanic field of Yunnan Province, China, using DEM visualization technology to generate rendered topographic maps and optical images of the volcanic area. We interpret and analyze the volcanic landforms, summarizing the geomorphic characteristics of different volcanic cones, lava units, and lava flow features formed during eruptions. By comparing the spatial distribution of lava units over different periods, we observe that newer lava units accumulate on older ones, exhibiting distinct morphological patterns in tomography. The distribution range of lava at different periods is clearly stratified. Our study proposes a reliable approach to mapping lava units, complementing traditional mapping methods in regions with thick forest cover. We complete the zoning map of lava flow units in the Heikongshan volcanic area using DEM maps. Compared to traditional volcanic geology mapping methods, DEM-derived boundaries of lava flow units are more accurate and less affected by challenging field observation conditions. Based on the DEM model and previous geological survey results, we classify Heikongshan’s eruptive activities since the Pleistocene into four stages, each with varying coverage areas. The early lava flows(Phase I)were primarily distributed north of the Heikongshan cone, extending eastward in a tongue shape. Middle-stage active lava flows(Phase Ⅱ)were mainly around the cone. In the late period, the activity’s scale and scope decreased, with small-scale tongue-shaped lava flows moving eastward(Phase Ⅲ)and small-scale sheet flows moving northward(Phase Ⅳ). Our findings provide volcanic geomorphic evidence for understanding the eruption history and offer insights into historical volcanic hazards. This information is valuable for volcanic disaster assessment and hazard evaluation in the future.

Key words: Heikongshan volcano, Tengchong volcanic field, DEM, Volcanic morphology, Lava flow unit