Definition
The information of various physical phenomena measured by various geophysical methods in surface or surface can be collectively referred to as information on the geophysical field.
classification method One
Earth's gravity field, geomagnetic field, land electric field, land temperature field, nuclear physics is naturally existing geophysical field; elastic wave is produced by artificial explosion The propagated elastic wave field, power supply to the underground to underground, electromagnetic fields, etc., which are used underground emission electromagnetic waves, and belong to artificial excitation geophysical fields.
classification method 2
The geophysical field can also be divided into normal fields and abnormal fields.
Abnormal field is a local geophysical field caused by the exploration object, such as a magnetic field generated by magnet mineral or magnetic rock mass in the presence of an underground, and this part of the magnetic field is overlooked in its surrounding rock and the other. Among the magnetic fields generated, when the magnetic field of the study, it is necessary to distinguish or extract the magnetine field; and the density of chromium iron is larger than the density of the surrounding rock, the density of salt rock body is smaller than the surrounding rock. Small density, both of which will cause local enhancement or weakening of gravity fields. Earth physics exploration is based on geological interpretation and inferior to the distribution characteristics of normal fields and abnormal fields.
Using
Artificially excited Earth's physical field, such as the elastic wave field produced by the explosion, the elastic wave is propagated in the boundary interface of different densities in the rock formation, reflecting, refracting and Energy attenuation, etc., according to the time of elastic wave returning to the ground to study the problems such as propagation speed, rock formation thickness, and production. The advantage of artificial scene is that the parameters of the field source are known, easy to control, higher resolution, and better geological effects, but cost is large.