China - Recent (CCTV - No access Chinese mainland)
1. Various of researchers, airborne electromagnetic detection system, helicopter in survey area; high-altitude geological survey in progress

China has successfully completed a high-altitude geological survey using its first helicopter airborne electromagnetic detection system, designed by the Aerospace Information Research Institute under the Chinese Academy of Sciences.

The system integrates key technologies such as high-sensitivity magnetic field sensors, wide-dynamic signal reception, and a stable airborne pod platform. It enables precise mapping of underground faults, fractures, groundwater, and mineral resources while identifying potential geological hazards.

During the two-month survey, research teams operated in extreme high-altitude and frigid conditions, conducting over 30 flight missions and covering more than 5,000 kilometers.

The system achieved a maximum detection depth of over 3,000 meters, providing critical data for the planning and construction of major national projects.

The airborne electromagnetic method (AEM) provides a rapid assessment of geological conditions as they relate to electrical conductivity or electrical resistivity. AEM uses a specialized transmitter to drive a time-varying current into a transmitter loop on an airborne platform. The transmitter loop generates an EM wave that propagates into the subsurface. As this energy encounters different subsurface layers or materials, it induces eddy currents that generate secondary EM fields. Secondary EM fields are detected by a receiver loop or magnetic antenna as the induced energy diffuses into the ground. The rate of diffusion indicates the resistivity of the subsurface materials.

Experts said that the system can play a vital role in supporting resource exploration and major infrastructure development.