Changchun Area Research Articles

The Application Example Analysis of Several Types of Composite Foundation in ChangChun Area

In this article, we analyse several types of composite foundation load test result, then expound that when we design composite foundations, we should choose reasonable kind of composite foundations according to accurate engineering geology and hydrogeology conditions and characteristic of buildings , otherwise will not reach the expected effect.

Study on Crustal Structures of Changbaishan-Jingpohu Volcanic Area using Receiver Functions

We have obtained 34 receiver functions from 71 teleseismic waveforms recorded by 34 stations that were installed in Changbaishan-Jingpohu volcanic area. Through inversing receiver function of 34 seismic stations, we obtain S wave velocity structures beneath the stations. The results revealed that the Moho depth is about 32-33km along Shenyang-Dunhua direction and becomes deeper toward its west side. In Changchun area, the Moho thickness reaches about 36km and under the crater of Changbaishan-Tianchi volcano, the depth of Moho reaches about 38km while beneath Jingpohu volcanic area, Moho depth is about 39km. Overall, the crustal thickness of studied area is thick in north and thin in south. We found an anomalous layer with obvious low Swave velocity beneath Changbaishan-Tianchi crater at about 10km depth. Beneath Jingpohu volcanic area there is also possibly a low S-wave velocity anomalous body at about 30km depth. The results show that the S-wave velocity gradients at Moho are obviously different between near crater and far apart from the crater. S-wave velocity gradient of Moho near crater is clearly smaller than that in area without volcano, which suggests that Moho structures beneath volcano are different from general Moho structures in other areas. The crust thickness on the two sides along Shenyang-Dunhua direction has a comparatively great changes and its location is almost the same as Dunhua-Mishan fault at near surface. Therefore, Dunhua-Mishan fault is a very important geological structure zone in the studied area.

Study on fluxes of CH4 emission from paddy fields in Changchun area

Little has been done in measurement and research of the flux of CH4 emission from paddy fields in Changchun area, Jilin Province, China before 1994. So the purpose of the study is to offer available regional data of CH4 emission flux and to discuss the factors which affect CH4 emission from paddy fields. Experimental paddy fields are chosen using TM pictures respectively in Xinlicheng (43°49′N, 125°20′E) of the Yitong River’s and in Wanchang (43°44′10″N, 125°53′11″E) of the Yinma River’s alluvial plain. The fluxes of CH4 emission from paddy fields are measured by the method of static chamber in Changchun area in 3 consecutive years. The research results show that the peak of CH4 emission from paddy fields occurs during the booting stage. The mean fluxes of CH4 emission are 7.056 mg/m(2 · h) and 0.489 mg/(m2 · h) in the paddy fields of flood and discontinuous irrigation respectively. The contrastive study holds that climate condition, the way of water management and fertilizer variation have significant influence on fluxes of CH4 emission from paddy fields. The difference of climatic conditions causes the interannual change of the flux of CH4 emission from paddy fields. In general, the flux of CH4 emission from paddy fields of flood irrigation is greater than that from paddy fields of discontinuous irrigation. To change the way of water management perhaps in an available way to reduce CH4 emission flux from paddy fields.