THE MECHANISM OF ELECTROMAGNETIC WAVE RADIATION DURING AN EARTHQUAKE

By using small natural rocks and some artificial crystals as samples we observed the electromagnetic waves which radiated during collision,friction or breaking. The experiments were well repeatable anywhere at any time without any screen. The radiation-spectrum of tens of kHz-500 kHz was obtained by using a frequency analyzer in the course of collision of two pieces of quartz. Experimental results showed that the impulses clustered within 200 kHz and the singnals of about 100 kHz were densest and strongest. The electric field strength at a point about 10 cm from the quartz could be as large as 69.8 mv/m,and the background strength about 14.5 mv/m. The fiels strength for quartzite was larger than that of granite by two orders of magnitude,and the field strength of quartz was larger than that of quartzite by the same .orders of magnitude. The rediation strength of rock depended evidently on the contents of quartzite. We found that crystal sugar,alum and ruby may radiate electromagnetic waves when they were breaking. The field intensity of waves radiated by a small sugar crystal at a distance 10 cm was 19 mv/m which could compare with that of quartzite. Even white quartzite sand may emit observable radiation. The smallest volume of fragment quartz which can radiate measurable electromagnetic waves is about 0.1 mm3.