震前卫星热红外环形应力场特征

The Annular Stress Thermal Field of Satellite Thermal Infrared Prior-earthquakes

本文包括两部分内容:①描述了1996年2月3日云南丽江Ms7.0级地震,震前几天的卫星热红外图像呈现圆形,它的NNW、NW、SN、及NE向的热旋扭面往S收敛。该地震地表破裂由一系列张扭性裂缝组成,呈左旋左列,水平位错不明显,垂直断距数厘米。垂直力对构造变动的作用较为明显;而丽江地震震源机制解破裂面II的走向NNE6o,倾向W,倾角44o,P轴方位为NNE3o、仰角75o,近于直立,综合热旋扭面展布、地震地表破裂特征及震源机制解,得出该旋扭椭圆为地幔外侧右旋上涌所造成;②菲律宾萨马岛Ms7.0～7.5强震群及青海共和Ms7.0地震前热应力环椭圆的推进路径。根据这一特征得出交变潮汐力的地球动力学解释。卫星热红外图像震前应力热场的方法是临震预测地震的有效方法,卫星热红外技术辅以震源机制解和地表破裂带力学分析是研究地球动力学有力工具。地球自转速度变化,交变潮汐力和地幔旋扭上涌力是地球动力学的主因。

This paper consists of two parts： in the first part the distribution of the rotation shear circle structure of the Lijiang Ms7. 0 earthquake of February 3, 1996. in Yunnan province is presented, combining the mechanics of the surface fracture with earthquake focus moment tensor solution. The Lijiang stress thermal circle can be seen in the satellite infrared images （1995-12-15T19：47, GMT）. Its diameter is about 250 kin（25.3° -28.3°N, 100. 1° - 103.2°E）. The ground fracture zone from Lijiang earthquake consists of a series of cracks with tension shear character. The cracks are rotated and arranged sinistrally, which did not possess obvious horizontal relative displacement with vertical displacement of centimetens. The vertical stress has the more obvious effect on the structural changes. In the focal mechanism solution, the second fracture plane is in NNE（6°） strike, inclining towards W with obliquity of 44°; Direction of P axis is NNE（3°）, its elevation is 75°. The uprush shear force causes the upcover layers above rotated, and the rotation shear force causes the shear rotation in the up-layers and results in en echelon arrangement faults, or annul faults and semi-annul faults. Synthesization of all above data confirms the characteristics of the rotation shear circle structure. We synthetically judge that the circle structure had dextro rotation and uprush movement. This is our first important conclusion. The second part presents the moving path of the thermal infrared anomaly of the Philippines＇ Samar island strong Ms7. 0 - 7.5 earthquake swarm and Gonghe M7.0 earthquake in Qinhai province. This is another exemplification on advancement path of the thermal rotational shear ellipse. On April 11 and 12, 1990, the satellite infrared imagery appeared a warming ellipse whose length was 1,500 km, width was 1,000 km, located E 92° - 110°, N 36° - 44°, temperature was 25 29℃. It was on the south side of the ellipse that Gonghe earthquake with Ms7.0 occurred on April 26. The rotational shear plane in the southeast of the ellipse tends to converge on N and disperses to S, the plane is of pressure shear nature. In the focal mechanism solution of Gonghe earthquake, direction of P axis is 45°, strike of the fracture plane is 135°（SE）, so that the outboard force of the ellipse was towards left, and the inboard force towards right. 17 days before Gonghe earthquake in Qinghai, at 05： 32（GMT） on April 11, 1990, upper part of the satellite image where is 98° - 103 °E, 39° - 43°N （ Gansu, Ningxia, Inner Mongolia） appeared as an isolated warming area. Temperature in Gaxun Nur lake and the Bajilin desert （42°N, 100°E） of north Gansu Province was from 25℃ to 29℃. The next day, at 05： 32（GMT） on April 12, 1990, the warming area expanded to the south and the west. Coomparing with identical time in different date, the isolated warming area about 100°E, 40°N at 05：32 on April 11 had greatly altered during one day along the way （ 100°E）. The warming area arrived 90° - 107°E, 35° -45°N, covering part Xinjiang, Qinghai, Gansu, Inner Mongolia and small part southern Mongolia. The warming area was a huge ring-like ellipse with length of approximate 2,000 km Advancement route of the stress thermal rotational shear ellipse. The pattern of the moving path suggests there are continuingly alternating tidal stresses in the earth. The thermal annulus before Samal Ms7.0 - 7.5 earthquakes in Philippines is a convictive exemplification. At 06： 32（GMT） on April 11, 1995, the satellite infrared imagery revealed a ring-like wanning ellipse （pink, 22℃ ） in NEtrending from the South China Sea to Philippine Luzon. At 05： 31（GMT） on April 12, the ellipse migrated to the southeast direction. At 05：31 （GMT） on April 13, however, the long ellipse turned its strike from NE to EW, and continually migrated approximately 300 km to south, its south most tip arrived at Samal. By now the ellipse entered the strong seismic zone on Philippines＇ E side. Then the stress thermal field continually developed. At 05： 31（GMT） on April 14 and 15, the warming image deformed from the elliptical annulus to the rectangle block whose length was 2,000 kin, width was 1,000 km, and the total warming area reached 2,000, 000 km^2. This phenomenon most likely is related to the alternant tidal action. Based on the infrared thermal abnormity characteristics, the strong earthquake swarms with Ms 7.0 - 7.5 occurred in Philippines＇ Samal island from April 21 to May 5 in 1995 was successfully forecasted. This phenomenon is connected with the alternant tidal action, and it is of some significance in coming earthquakes. All theories originate from practice and serve practice. The ＂Red Swelling＂ by academician Fu Chengyi on earthquake genesis is presented about 36 years ago. But A new hypothesis ＂the positive hole charges＂ was born in 2002 and 2003. The phenomenon of bright temperature increases observed from thermal infrared channels on stationary weather satellites before a strong earthquake has been used as a precursor to earthquake for more than ten years. In 1990＇ s, there were only a few reports in Science in China and Chinese Science Bulletin and even less reports on its＇ mechanism. At the beginning of this century, Dr. F. Freund and D. Ouzounov（ Professor of physics at San Jose State University and NASA＇ s Ames Research Center） did rock strike experiment on nonconductive igneous rock core samples and observed that ＂the positive hole charges＂ becomes active when the samples was stroked, the electro-magnetic emission on infrared band was also recorded. This supports that there are infrared emissions from rocks when rocks are under pressure before earthquakes. Practice is the standard to prove truth. Satellite thermal irffrared technique was put into practice shortly. During the 11 years from 1990 to 2000, we made 119 predictions, of which 58 were valid and 15 were false alarms. 11 earthquake predictions Ms≥7.0 and 28 earthquake predictions Ms ≥6.0 are comparatively good. The success rate of those predictions increased from 24% during period of 1990-1995, to 46% in 1996, 53% in 1997, 76% in 1998, and 80% in 1999 and 2000, as summarized by Wang Chunyin in her M A Candidate （2005）. The satellite infrared detected thermal stress field is a reflection of the earth＇ s crust stress condition when rock stress increases the spots along the stress produce micro fissures in rock. Therefore, hot planes and lines that are closely related with the stress condition and the rock faulted structure can demonstrate the compression stress direction. The satellite thermal infrared hot stress field＇ s technique was an outstanding example of integrating theory with practice and of making theoretical innovations. The method of using satellite thermal infrared images combined with pre-earthquake hot stress field analysis to predict impending earthquake is valid. Combining the satellite thermal infrared technology and earthquake focus solution and dynamic analysis of surface fracture zones is an innovative and effective method for earth dynamic study. The earth rotation speed rate change, alternative tidal force and rotation shear uprush of mantle are the main earth dynamic sources.