Research On Seismic Thermal Radiation

To extract anomaly seismic radiation is the key point in the research of seismicthermal radiation, because it is an exception message which lost in the complexbackground of weak information. In this paper, we effectivly removed the non-seismicfactors and highlighted thermal radiation of seismic anomalies by using the method of"Time-frequency relative power spectrum". It is easy and convenient to operate andreduce identifiable differences caused by experiences.The quite black-body radiation (TBB) and outgoing longwave radiation (OLR) datawe used is from Chinese Geostationary Meteorological satellite FY-2C/2E. Weobtained the time-frequency space data with the dominant frequency and amplitude bythe Wavelet Transform and the treatment of the relative power spectrum. Then weextracted seismic radiation anomalies by scanning time-frequency data with themethod of time-frequency map in whole space-time and full band. In this paper, weanalysised the characteristic of85earthquakes above Ms5.5radiation anomalies, anddeveloped processing software which is used for data processing of geostationarysatellite FY-2C/2E seismic thermal radiation.In analyses of earthquake cases, we gained the results as follows:(1) There are significant thermal radiation anomalies both before and after nearly95%of earthquakes in these cases. It is easy to extract and identify such seismic thermalradiation anomalies by using of "the relative power of time-frequency spectrum". Theoverall performance expanded first and narrowed later. It may be the result ofwarming and cooling. The warming is due to a rapid increasing in the accumulationregional area and stress, and the atmosphere at bottom is rising which caused by thegreenhouse gas emissions during fault sliping. The cooling of ground (sea) airtemperature is caused by atmospheric conditions.(2) There exists evidently characteristic period and magnitude of thermal abnormalradiation before and after earthquakes. In terms of the mainland, there is a long cyclein drought areas, but shorter in wet areas. The characteristic period of mostly oceanicearthquake is30days or less. Characteristic magnitude is more than6times thannomal. (3) Thermal radiation anomalies are closely related to the geological structrre. Theabnormal distribution and geological structure (fault strike) are basically the same.Seismic radiation anomaly also has differences in region, such as between sea andland, wet areas and dry regional, and in latitude.(4) Thermal radiation has obvious characteristics in abnormal duration, scope andabnormal morphology. The duration is between one and six months and varies indifferent regions. There are quite different in oceanic and continental earthquakes.Abnormal area is between500and5000square kilometers and has no obviouscorrespondence with the magnitude. Earthquakes occurred within or at the edge of theabnormal transitive region which anomalies appeared and disappeared. The majorityof earthquakes appeared repeatedly with the thermal radiation.(5) This is the first comparative study on thermal infrared anomalies and long-waveradiation anomalies. Their timing curves and the temporal evolution matched well andhad a good consistency in the abnormal area. Anomalies appear in the vicinity of theearthquake. The abnormal timing consistency is poor; mainly different in the durationand the first occurrence of periods. Besides, there also are different in thecharacteristic period.Currently, depth study of the prediction index of magnitude is still not enough. Spaceobservation plays an important role on seismic research or earthquake prediction withthe development of satellite remote sensing technology and the accumulation ofsatellite observations and the continuous further application on the remote sensingdata and seismic research.