Geophysical surveys
In geophysical surveys targeting mineral and geothermal resources exploration, airborne electromagnetic, magnetic, gravity, radioactive surveys and electric, magnetic, gravity surveys on the ground are carried out in order to estimate underground structures, such as resistivity, magnetics and gravity, from an analysis of measuring results. We prepare plane and sectional maps and three dimensional analytical maps of various analyses of each survey method. We also conduct ground surveys and fault investigations using microtremor array surveys which observes minute ground vibrations.
1. Electrical and electromagnetic surveys
Electrical surveys are a method of investigating underground electrical characteristics from the response of the current flowing to the ground. These consist of resistivity surveys and IP surveys. Electromagnetic surveys are a method of investigating underground electrical characteristics from the response of electromagnetic waves transmitted from the ground surface and the air. These consist of MT, AMT, CSAMT and TEM surveys.
They are suitable not only for exploration of underground mineral resources but also for civil engineering surveys of landslides and scientific investigations of faults and volcanoes.
AMT method measuring sites
2. Gravity and magnetic surveys
Gravity surveys are a method of measuring gravitational acceleration. The ordinary method is to measure this on the ground, but the latest technology has been applied to alternate methods, such as the airborne gravity deviation method. Magnetic surveys are a method of observing geomagnetism on the ground surface and by airplane. Both methods are suitable for exploration of mineral resources, petroleum, natural gas and geothermal resources, and investigating faults and volcanoes. Gravity surveys are also used for surveys of cavities near the ground surface, and magnetic surveys are also used for investigations of buried metal objects.
Measuring site used in a gravity survey in Japan.
Workers with equipment used in a magnetic survey in Chile.
3. Microtremor array surveys
Microtremor array surveys are a method of observing weak vibrations (microtremors) in the ground surface with multiple seismometers, and investigateing the propagation velocity of underground seismic waves.
This is suitable for ground surveys of various sizes, the exploration of various mineral resources and investigating faults and mud volcanoes. This is attracting attention as a new method for underground structure investigation.
Measuring equipment used in a microtremor array survey.
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Sumiko Resources Exploration & Development Co., Ltd
Exploration and Environmental Survey Department
Address: 33 Mori Bldg. (5F), 8-21 Toranomon 3-chome,
Minato-ku, Tokyo, 105-0001, Japan
TEL：+81-3-5405-2172 /
FAX：+81-3-5405-2175