Volcanic Stratigraphy and Potential Hazards of the Chihsingshan Volcano Subgroup in the Tatun Volcano Group, Northern Taiwan

Abstract

The Chihsingshan Volcano Subgroup (CVSG) is one of the most important landforms located within the Tatun Volcano Group in northern Taiwan. Based on a Digital Terrain Model, contour maps and field investigations, the CVSG can be divided into four types of volcanic landforms: (1) a strato- or composite volcano, Chihsingshan; (2) domes, the Shamaoshan and a hidden unit; (3) lava cones, the Baiyunshan and the Hsiaotsaoshan; and (4) a scoria cone, the Chikushan. Meanwhile, many small craters are distributed linearly along two northeast trending normal-fault systems. The occurrences are predominantly lava flows with subsidiary fall deposits, pyroclastic flows, and lahars in which at least twenty layers of lava flow in the CVSG can be recognized. Among them, 16 layers in the Chihsingshan volcano, named as C1 - C16, two in the Baiyunshan, B1 - B2, and two in the Hsiaotsaoshan, H1 - H2. Our study suggests that the potential volcanic hazards include lava and pyroclastic flows and simultaneous or subsequent lahars, if the Chihsingshan erupts in a similar manner as in the past. A volcanic hazard zonation map can be constructed for the purpose of mitigation assuming the future eruptive center and eruptive volume.

Keywords

• Tatun Volcano Group
• Chihsingshan Volcano Subgroup
• DTM
• Lava flow
• Volcanic hazards