Abstract:The application of geomagnetic measurements is mainly focused in two areas.The first is scientific research, national defense, and national economic and social development, such as mineral exploration.The second is to serve earthquake monitoring and prediction.Seismo-geomagnetic field measurements are regularly repeated measurements at several points in the field using a high-precision magnetometer.The purpose behind taking such measurements is to research the temporal change and spatial distribution of the local geomagnetic field before and after earthquakes.In the field, a survey grid or line is used for obtaining geomagnetic observations, the spatial coverage of which is generally not less than 150 km×150 km for a survey grid and not less than 200 km for a survey line.In addition, the distance between measuring points is usually 5~40 km.For the measurement of total local geomagnetic intensity using mobile observations, two survey pegs (main and vice) were installed at field observation points.These observations were synchronized with a station that records the diurnal geomagnetic variation using a specialized instrument installed under the same conditions as for high-precision magnetic measurements.The purpose of this was to reduce or eliminate short-period and diurnal variations (Sq) of the geomagnetic field.After the Xingtai Earthquake (1966), mobile seismo-geomagnetic observations were initiated.Different from global geomagnetic measurements, the observation stations were generally set in earthquake regions or around active faults.Moreover, the repeated period of measurement was relatively short, i.e., usually four times per year.However, irrespective of the form of measurement, a manual method for synchronizing the observations from the measuring stations in the field with the diurnal stations is necessary.Single independent magnetometers in the field cannot transmit data from the diurnal stations to the scene of the field observations in real time;therefore, the final data processing cannot proceed in a timely manner.Furthermore, data observed in the field and at the diurnal stations cannot be highly synchronized, which greatly affects the precision of the results and the efficiency of the fieldwork.In the current circumstances, the observation results and the report of the seismic regime are generally submitted 1~3 days after an earthquake, following which, many more days are required to obtain the observational data and to generate the reports.This is far from adequate for meeting the requirements of observations and field monitoring in the case of an emergency.Therefore, the development of a synchronous control system of seismo-geomagnetic measurement in the field is of great significance.A synchronous observation system with a wireless network was developed according to the requirements of seismo-geomagnetic field observations.The system consisted of an interface unit, data acquisition control unit (CPU), wireless unit, transport network, and computer control terminal.This system is easy to operate, practical, and will in time transfer data measured by the mobile geomagnetic diurnal stations and the field measuring points.The system has service functions such as remote wake-up, hibernating, and time correction.Overall, the system could reduce the field workload of observers, increase the working efficiency of field measurements, and could be used for the transmission of observations from the geomagnetic array.
