The present invention relates to an apparatus for detecting electromagnetic waves that are generated due to activity in the natural world. More particularly, the present invention relates to an apparatus for detecting a change of electromagnetic waves generated as a premonitory symptom of earthquakes.
By the movement of various plates constituting the earth crust of the earth, complicated stress occurs between the plates. In particular, Japan undergoes a large-scale earthquake regularly because of being located in the place where the plural plates interfere with each other, and gets into danger. From such a point of view, the prediction of the earthquake is extremely important and urgent. However, unfortunately, the earthquake prediction to specify the time and the place of the earthquake generation is not yet possible at the current science standard.
In regards to an earthquake prediction method based on the earthquake prediction or the observance of the electromagnetic waves or an observing method of electromagnetic waves in the natural world, some technologies have been suggested, as disclosed in the following documents.
Patent Document 1
    Japanese Patent Application Laid-Open (JP-A) No. 63-184088Patent Document 2    JP-A No. 54-133174Patent Document 3    Japanese Utility Model Application Laid-Open (JP-U) No 03-060094Patent Document 4    Japanese Patent No. 3188609
Among them, the inventions disclosed in Patent Documents 1 and 2 are directly related to the earthquake prediction. The invention disclosed in Patent Document 1 relates to a technology for predicting the earthquake by inserting an antenna into a deep well and measuring radio waves in the ground. The invention disclosed in Patent Document 2 relates to a technology for transmitting artificially transmitting radio waves and predicting generation of the earthquake based on abnormality of a reception state of the radio waves at a receiving side. However, uncertain elements are excessively large, and the prediction of the earthquake based on the specific time and place is impossible in actuality.
The invention disclosed in Patent Document 3 relates to a technology for mainly specifying a vibration source other than the earthquake or the seismic origin, rather than the prediction. Finally, the invention disclosed in Patent Document 4 is developed and patented by the present applicant. In this invention, for example, electromagnetic waves that are used as communication and broadcasting means of radio broadcasting are measured, components that are considered as noises generated from the natural world are extracted from the measured electromagnetic waves, and abnormality of the earth crust is estimated based on a change in the number of generation of the noises.