青藏高原地震前CO的排放与卫星热红外增温异常

CO RELEASE FROM THE TIBETAN PLATEAU BEFORE EARTHQUAKES AND INCREASING TEMPERATURE ANOMALY SHOWING IN THERMAL INFRARED IMAGES OF SATELLITE

地震前卫星热红外图像的亮温异常与地球的排气作用有关。由于以往仅在个别点上对CO2、CH4等气体取样或监测,对这些温室气体震前排放的范围缺乏足够的了解。用美国EOS卫星携带的MOPITT探测仪资料,获得了2000年4月30日CO在青藏高原大面积逸出的情况,图像显示CO含量异常升高的区域具形状不规则的圈层结构,累计长度约3200km,总面积约267万km2,其CO体积分数值内高外低,体积分数最大的区域(31×10-8≥φ(CO)>27×10-8)大致呈EW向分布,长约800km,宽约280km,面积约22.41万km2。整个CO逸出区φ(CO)为2002年正常值的1.57～4.10倍,与从卫星热红外图像上发现的2000年4月29～30日在青藏高原上的大面积多处孤立升温有较好的一致性,且这种CO逸出的现象至少在2000年4月30日之前的数天内是持续存在的,它们都是2000年6月6日甘肃景泰Ms5.9地震及2000年6月8日缅甸北部Ms6.9地震的前兆。这一方面说明,气—热震兆机理是有实际依据的,同时也反映了青藏高原上空臭氧层空洞或低值中心的出现可能与CO气体在高空中的不断氧化有关。

The anomaly of increasing temperature which can show in thermal infrared images of satellite before earthquakes relates to the gases release from the crust. Because the gases such as CO (2) and CH (4) were monitored or sampled only on a few sites, scope of the gases release before earthquakes were not understood enough. From MOPITT data of America EOS satellite, we found a large-scale discharge of CO from the Tibetan Plateau on April 30, 2000 (before it, CO continuously released at least for some days). The image shows that the area with abnormally higher CO content bears circle structure with irregular forms, its accumulative length and area respectively were about 3200 km and 2.67×10^(6) km^(2), and volume percentage of CO is higher in inner circles than that in outer ones. The region with the largest CO volume percentage (31×10^(-8)≥φ(CO)>27×10^(-8)) distributes roughly in EW direction with the length about 800km, width about 280 km, and area about 22.41×10^(4)km^(2). φ(CO) in the anomaly area was about 1.57~4.10 times the normal value observed in January, 2002. This phenomenon has a good coherence with large-scale temperature increase on several sites of the Tibetan Plateau from April 29 to 30, 2000. All of them are precursors of the earthquake with Ms 5.9 at Jingtai, Gansu province, June 6, 2000 and that with Ms (6.9) in the north of Burma, June 8, 2000. This means that gases-hot mechanism of earthquake precursors is truthfulness, and low value center of ozone over Tibetan plateau may relate to oxidation of CO in the upper air.