3-D cave mapping in the karst region of Batu Katak, Northern Sumatra, Indonesia

Abstract

Batu Katak village in Northern Sumatra, Indonesia, is located on the Triassic Batumilmil Formation, consisting of dark grey to reddish-grey limestone with palaeokarstic horizons and features. A small group of scientists from the University of Puerto Rico and Harimau Conservation explored the neighbouring karst forest and mapped 5 caves as a conservation action, to help protect the karst forest and its geological importance. As across the rest of Sumatra, this region is impacted by palm-oil farms, illegal deforestation, poaching and mining. The goal of this study was to verify the safety of the cave environment and establish the cartography of the caves that surround the village: Water Cave, Pupuk Mentar Cave, Mbelin Cave, Sibayak Cave, Jodoh Cave. A total of 1.2km of cave passage was surveyed, with 126.6 million data points collected. The cartography was created using the Geoslam ZEB1 LiDAR and the data were processed using Matlab. Environmental parameters recorded included the pH and temperature of the water or soil in the cave, and also the relative humidity. The cave maps and the measurements of environmental parameters are being used to help enhance local ecotourism practices and inform future research into understanding the unique karst habitat biodiversity. This includes trogloxene species such as bats, snakes, cave swallows, and many more, as well as the Sumatran tiger. Based on physical evidence noted during the study, this latter, critically endangered, species has used one of the caves as a habitat.