关键词: 大地电磁测深, 视电阻率, 磁感应矢量, 低阻体, 岩浆囊

Abstract: Observations of magnetotellurics have been carried out at 46 sites along five profiles in shape of umbrella and along a northwest direction profile in the Tianchi volcano area and its vicinity in Changbaishan Mountain northeast China. There are 61 sites including 15 sites which were done in early time. The data processing has been made by using the Robust technique. High S/N ratio resistivity and phase have been obtained. The Bahr’s impedance tensor decomposition was applied for eliminating distortion. The induction arrow vector was calculated. The two-dimensional inversion method (RRI) is used for data interpretation. The results show that (1)There is low resistivity correspondence Tianchi water pool near the surface. There are four low resistivity zones corresponding to Jingjiang hot spring, Julongquan hot spring, gate of mountain and its vicinity and Shuangmu peak at the depth of above 5 km.(2)Low resistivity body at the depth about 12km is located the carter and its north and east area. The body is 20 to 30km thick and 15～25km wide. It is inferred that this anomaly body may be a magma chamber. (3)The crustal electric conductivity structure has obvious difference in direction of SN in this area. There is a high resistivity zone in the south part and low resistivity zone in the north part.

Key words: Magnetotelluric, Apparent resistivity, Induction arrow vector, Low resistivity body, Magma chamber