Upward Magma Migration within the Multi-level Plumbing System of the Changbaishan Volcano (China/North Korea) Revealed by the Modeling of 2018-2020 SAR Data

Abstract

Changbaishan volcano (China/North Korea border) consists of a cone with a summit caldera and last erupted in 1903. An unrest episode occurred between 2002 and 2006, followed by subsidence. The volcano was responsible for the largest eruption of the last Millennium in 946 CE and it is characterized by a multi-level plumbing system. Here, we analyze the Changbaishan 2018-2020 deformations by using remote sensing data, detecting an up to 20 mm/yr, NW-SE elongated nearly-uplift of its southeastern flank and a -20 mm/yr nearly-subsidence of the southwestern flank. Modeling results show that three active sources are responsible for the observed ground velocities: a deep tabular deflating source, a shallower inflating NW-SE elongated spheroid source, and a NW-SE striking dip-slip fault. The depth and geometry of the inferred sources are consistent with independent petrological and geophysical data. Our results reveal an upward magma migration from 14 km to 7.7 km. The modeling of the leveling data of the 2002-2005 uplift and 2009-2011 subsidence depicts sources consistent with the 2018-2020 active system retrieved. The past unrest is related to pressurization of the upper portion of the spheroid magma chamber, whereas the subsidence is due to crystallization of its floor, this latter reactivated in 2018-2020. Therefore, Changbaishan is affected by an active magma recharge controlled by a NW-SE trending fault system. Satellite data analysis is a key tool to unravel the magma dynamics at poorly monitored and crossborder volcanoes.