关键词: 地震异常, 潜热通量, 异常相关性, 腾冲火山, 遥感

Abstract: Domestic and foreign scholars found that SLHF anomaly occurred before some strong earthquakes in coastal area or in inland region with abundant water. The author noted that SLHF anomaly in some special tectonic position is not only associated with the strong earthquakes nearby but also with the strong earthquakes far away in the same tectonic belt. The dynamic variation rule of SLHF anomaly in the special tectonic position prior to earthquakes might reveal some trend of regional seismic activity and contribute to the research of mechanism of SLHF anomaly prior to earthquakes. Tengchong area in Yunnan Province is such a special tectonic position located in the south of the eastern Himalayan syntaxis and is one of the youngest volcanic regions on the Chinese mainland with frequent magmatic activity and strong hydrothermal activity.The earthquakes (M_S≥6.4) since 2000 in Sichuan-Yunnan region(including the Yao'an M_S6.5 earthquake in 2000, the Ning'er M_S6.4 earthquake in 2007, the Wenchuan M_S 8.0 earthquake in 2008, the M_S7.0 Myanmar earthquake in 2011 and the Lushan M_S7.0 earthquake in 2013)are selected as cases to study the variation characteristics of the SLHF in Tengchong region before and after the above earthquakes.It is found that significant SLHF anomalies occurred in Tengchong area not only before earthquakes happening in the vicinity but also earthquakes far away in the surroundings. The SLHF anomalies occurred mostly within one and half months before the earthquakes, except Wenchuan M_S 8.0 earthquake. The SLHF anomalies occurred two months before Wenchuan earthquake, the earlier occurrence of the anomalies might be due to the relatively long distance between Wenchuan earthquake and Tengchong area. It is also found that the amplitude of anomaly is related to earthquake magnitude, the larger the magnitude of earthquake, the larger the amplitude of the anomalies. For example, the SLHF anomalies in Tengchong region prior to Burma M_S 7 earthquake and Wenchuan M_S 8.0 earthquake are very strong, far more than the reference maximum values, but the SLHF anomalies prior to Yao'an M_S 6.5 earthquake and Ning'er M_S 6.4 earthquake are relatively small.The sensitive response of SLHF in Tengchong region to the surrounding earthquakes on the one hand is related to the development of active faults and the present-day intensive crustal deformation;on the other hand, there are strong volcanic activities in Tengchong area, with springs widely developed and water heat exchanging quickly. So as a result, the SLHF of this region is sensitive to surrounding tectonic movement.

Key words: earthquake thermal anomaly, surface latent heat flux, association between SLHF anomaly and earthquakes, Tengchong volcano, remote sensing