[S26-1] Exploring connections between heat flow and tectonics I

[S26-1-05] Numerical Simulation of the Geothermal Effect of the Millennium Eruption of the Changbaishan Tianchi (Mt. Paektu) Volcano at Sino-North Korean Border

^○Wentao Duan¹, Ting Ke¹, Shaopeng Huang^1,2, Xiaoyin Tang¹ (1.Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an, China, 2.Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, US)

The eruption of the Changbaishan Tianchi Volcano (CTV, also known as Mt. Paektu Volcano) in around 1000AD ejected about 100 cubic kilometers peralkaline rhyolites. It was one of the largest explosive eruptions in the world over the last 10,000 years. Volcanic eruptions are associated with a vast amount of heat being carried from the greater interior to shallower depths by magmatism. Therefore, volcanic areas are generally rich in geothermal resource. Numerical simulation is an effective means not only in the research of thermo-tectonic evolution of the lithosphere, but also in the assessment of geothermal energy potential in a volcanic area. Here we simulate the thermal effects of the magmatism with ANSYS WORKBENCH, a finite-element simulation software platform that has been widely used in engineering thermophysics, but so far rarely applied in a geothermal research. Based on the latest geothermal, petrological and geophysical data, we construct two conceptual models to simulate the thermal effects of the CTV Millennium Eruption. Petrological studies indicate that the erupted CTV rhyolites were derived from the upper-middle crust at depths of about 10-15 km; whereas recent magnetotelluric sounding and analysis of Advanced Land Observing Satellite PALSAR data suggests that the magma chamber is located in the upper crust beneath the depth of around 8 km. Consequently, our two conceptual models represent the upper crust and upper-middle crust magma chamber scenarios, respectively. Simulation result shows that in either case, the conductive thermal diffusion of the magma activity of the CTV Millennium eruption 1 kyr ago is restrained within the range of 500 meters from the intruded magma column. This might be part of the reason for the lack of widespread hydrothermal activities in the CTV area.