[S-IT19] Coupling of deep Earth and surface processes

[SIT19-06] Electromagnetic Investigation of the Western Pacific Asthenosphere Using the Probabilistic Inversion

*Hogyum Kim¹、Kiyoshi Baba²、Sang-Mook Lee¹、Hisashi Utada² (1.Seoul National University、2.Earthquake Research Institute, The University of Tokyo)

キーワード：Magnetotelluric Method, Ocean Bottom Electromagnetometer (OBEM), Probablistic inversion

The magnetotelluric (MT) study using ocean bottom electromagnetometers has demonstrated effectiveness in examining the mantle structure of oceanic plates. The method's advantage lies in its sensitivity to various factors such as temperature, composition, presence of melt, and other critical properties associated with mantle processes. Thus, the method has been widely applied to study mantle structures and discontinuities. Recent advancements in modern inversion software and reduced computation costs have facilitated applying probabilistic inversion techniques for MT. Probabilistic inversion can contribute to MT investigations by providing additional insights, including probability density distribution, interface probability distribution through methods like the reversible jump Markov chain Monte Carlo algorithm, and potential joint interpretation with other geophysical or petrological constraints. In this study, we applied probabilistic inversion to 1-D MT response functions obtained from the western Pacific basins to explore the nature and structure of the asthenosphere beneath the oceanic plate, as well as to identify potential boundaries and discontinuities.