Details of the Abstract
| Title of paper | Induction arrows in Eastern Tibet |
| List of authors | Author, A.V. Tereshyn, Co-author, I.I. Rokityansky |
| Affiliation(s) | Subbotin Institute of Geophysics of the National Academy of Sciences of Ukraine, Kiev, Ukraine |
| Summary | In the eastern Tibet, large-scale motions of the crust occur. For their explanation crustal flow channels were proposed and geophysical data are necessary to constrain the pattern of the flow. Electromagnetic studies are promising for this purpose. 54 geomagnetic observatories of Chinese network were carefully processed for 2008-2019 years and tippers (VTF, induction arrows) were estimated at periods 300 - 10000 s Unusually large tippers were discovered at three observatories in eastern Tibet (Xu et al 2023). The authors were so surprised that they titled the article in a rather strange way. They compiled model: 1000 km long, 100 km wide, 10 km thick conductor (Figure 1) at the depth 5 km in highly resistive ρe=10000 Ohm∙m half-space ignoring high conductivity of the Earth’s mantle. We calculated the anomalies from this model with and without conducting mantle – the tipper’s values differ in ≈2.5 times. So, for realistic Earth (with conducting mantle) this model doesn't explain the experimental data on large tippers. All great arrows directed to west. We supposed that anomalous body plunges along an eastward inclined plane of Jinshajiang suture zone. We collected MTS data which show conducting layers in upper crust, which can strongly screen anomalous fields from the eastern submerged edge of the anomaly. The western edge most likely located at shallow depths. However, to attain observed arrows ≈3 units, also super-channeling effect should operate. It occurs in the places where strong decrease in the longitudinal conductance located. Results of the modeling will be given in presentation. |
| Session Keyword | 2.0 EM theory, modelling and Inversion |
| File upload |
2.0_induction_arrows_in_easte_tereshyn_02.pdf
2P63.pdf |