Satellite Thermal Infrared Anomalies before Earthquake

Satellite Thermal Infrared Anomalies before Earthquake

Qiang Zuij
(Institute of Geology, state seismological Bureau)

Xu Xiudeng
(Department of Geography, Zhejiang Normal University)

Dian Changgong
(Satellite Meteorological centre, State meteorological Bureau)
China

Abstract
The temperature anomaly prior to earthquakes has already been discovered, but how to identify thermal anomalies before earthquakes is still a difficult problem is present day’s earthquake prediction. Only new observational methods are successfully developed, can it be possible for us to overcome this difficulty . It is very difficult for us to set up stations on ground in such a large area to observe geochemical and geophysical phenomena of various seismic activates and to capture the instantaneous variation. The satellite telemeter can measure these phenomena quickly and cover a large area. Because the precision of the temperature value of every interface (surface, water level and cloud-veil surface) measured by satellite thermal wave is high, the shortcomings mentioned above can be solved using the telemetering.

Thermal Infrared Anomalies before Earth Quakes
In the second half of last year, we began studying the relation between the satellite thermal infrared anomaly and seismic activity. Firstly we researched the Lancang-Gengma earthquake, Yunnan Province , which occurred at 13h 21m of November 6, 1988. By comparing two thermal infrared photos prior to the quake at the same time of different dates, it can be seen clearly that the temperature on November 6 increased relatively to that on November 5. According to the distributed features of the temperature, the region covered by the photos can be divided into three areas: the central-east part of the photo is the increased temperature area, the entire temperature south of Nandinghe river and yuangjiang river is higher, most is 288°-289° K (15°-16°). The topographic boundary lines of the mountains and rivers are distinct, the tectonic activity is strong, and the crust degases fiercely. The temperature in the oceanic trench rises, and gas diffuses upwards and covers the crest. The risen temperature of the crest changes the original green color (dark gray) into yellow color (bright gray). The NE crest from Jingheng northward is the most prominent one (N22, E101) . The similar phenomenon also appears in the vicinity of southern Meng’a (N21°-22° , E101°-102° (satellite photos 1,2); the northeastern corner of the photo, Kunming area, in green colour (dull grey) , the variation of the difference in temperature is not obvious and relatively stable , most is 283°-284° K (10° -11°C) . It is shown that the crustal movement here is comparatively quiet; the third area is a transitional zone of the two areas mentioned above, which is located at Tonghai-Yuangjiang (N24°-E103°), that is the crossed zone of the change of the difference in temperature, yellow alternating with green (alternated belt of dark grey and light grey) and the temperature increase phenomenon is medium (satellite photos 1,2)

Photo 1. Satellite image of temperature increase in Langchang-Genma area on 5 Nov. 1988

Photo 2. Satellite image of temperature increase in Langchang-Genma area on 6 Nov. 1988
There occurred moderately strong earthquakes of M5.7 and 6.1 in Datong –Yanggao area, North China on 18 and 19 October last year. The satellite thermal infrared anomaly was very outstanding several days (at 19 hr on 17 and 18 October), 1989) under the normal meteorological background condition, the temperature in the river valley of the Sanggan River, southern flank of Datong Yanggao (N39.5°, E113°- E114° ) changed from 273°-274° K to 278°-279° K (0-1° C to 5-6°C), and that from 279° to 284° K (6°C-11°C) in between Laiyuan Country and tanxian county, Hebei province. When the mainshock occurred at one o’clock , on 23, October minus that on 19 October, we obtained a real (absolute) temperature increase map. A satisfactory result was obtained. The temperature increase value in most plain and lowland areas is zero or close to zero and the crests in Wutai mountain, Hengshan mountain (N41°, E115°) are relatively temperature increase areas. The temperature increase is 4-5°C (satellite photo3). It is shown that the gas from the underground spread upwards everywhere as the time proceeded.

Photo 3. Satellite image showing the purre increasing value compa-ring with the two image of the thermal infrared anoma-lies on 19 and 23 Oct. 1989 in datong area.
Formation Mechanism of Seismically Thermal Infrared Anomaly
It is known from the observation of thermal infrared photos of satellite that the temperature of the earth surface has its normal meteorological setting and the crystal stability. Because the temperature can be observed around the clock by the satellite infrared radiometer, the time-space variation of the temperatures on the earth’s surface and on the top of clouds can also be observed. All bodies always emit infrared radiation continuously unless their temperatures have reached the absolute zero. When the crust is compressed and before major fractures have reached the absolute zero. When the crust is compressed and before major fractures occurring micro cracks often occur around the epicentral area and the variation is extremely fast while carbon dioxide, steam, hydrogen and methane can be gas escape from the underground and diffusion to the space, the gases suck up the solar radiation. Under the actions of the stress enhancement and the excitation of the electromagnetic field, the infrared radiation is emitted and the seismically infrared anomaly will occur around the seismogenic region.