Abstract—The three-dimensional (3D) interpretation of magnetotelluric (MT) data in the Koryak–Kamchatka region with interactive fitting of 3D model MT curves and magnetovariational matrices to their measured analogs is used to construct geoelectric sections of the upper part of the lithosphere. Based on the obtained sections, aqueous fluid fraction and melt fraction in the crust and upper mantle is estimated. Fluid saturation is determined with the allowance for temperature and pressure growth with depth for the rocks saturated with NaCl brine with concentrations 100 or 170 g/L. The degree of fluid mineralization is specified based on the P-wave velocity distributions obtained by deep seismic sounding and tomography. Fluid fraction and mantle melt fraction are estimated from the simplified Shankland–Waff formula (modified Archie’s law). The maximum fluid and melt fractions are characteristic of the lithospheric blocks located within seismically and volcanically most active structures and within regional faults cutting these structures. The blocks with high melt and fluid fraction are spatially correlated with the domains of low P-wave velocities.

摘要— 科里亚克-堪察加地区大地电磁 (MT) 数据的三维 (3D) 解释与 3D 模型 MT 曲线和磁变矩阵与其测量模拟的交互拟合用于构建岩石圈上部的地电剖面. 根据获得的剖面，估计地壳和上地幔中的含水流体分数和熔体分数。流体饱和度是通过允许温度和压力随深度增长的 NaCl 盐水饱和的岩石而确定的，浓度为 100 或 170 g/L。流体矿化程度是根据P指定的-通过深地震测深和层析成像获得的波速分布。流体分数和地幔熔体分数是根据简化的 Shankland-Waff 公式（修正的阿尔奇定律）估算的。最大的流体和熔体分数是位于地震和火山活动最活跃的构造内以及切割这些构造的区域断层内的岩石圈块体的特征。具有高熔体和流体比例的块体在空间上与低P波速度域相关。