A study on crustal structures of Changbaishan2Jingpohu volcanic area using receiver functions

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1 CHINESE JOURNAL OF GEOPHYSICS Vol. 48, No. 2 Mar., 2005,,..,2005,48 (2) : Duan Y H, Zhang X K, Liu Z,et al. A study on crustal structures of Changbaishan2Jingpohu volcanic area using receiver functions. Chinese J. Geophys. (in Chinese), 2005, 48 (2) : ,,,,,,,, ,, S., 32 33km,, 36km. 38km, 39km.. 10km ; 30km ; S. S S,.,,.,,, S, (2005) P , A study on crustal structures of Changbaishan2Jingpohu volcanic area using receiver functions DUAN Yong2Hong, ZHANG Xian2Kang, LIU Zhi, YUAN Qin2Xi, XU Zhao2Fan, WANG Fu2Yun, FANG Sheng2Ming, YANG Zhuo2Xin Research Center of Exploration Geophysics, China Earthquake Administration, Zhengzhou , China Abstract We have obtained 34 receiver functions from 71 teleseismic waveforms recorded by 34 stations that were installed in Changbaishan2Jingpohu 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 Shenyang2Dunhua direction and becomes deeper toward its west side. In Changchun area, the Moho thickness reaches about 36km,and under the crater of Changbai2Tianchi volcano the depth of Moho reaches about 38km, while beneath Jinpohu volcanic area, Moho depth is about 39km. Overall, the crust of studied area is thick in north and thin in south. We found an anomalous layer with obvious low S wave velocity beneath Changbai2Tianchi crater at about 10km depth. Beneath Jingpohu volcanic area there is also possibly a low S2wave velocity anomalous body at about 30km depth. The results show that the S2wave velocity gradients at Moho are obviously different near and far from the crater. The gradient near crater is clearly smaller than that in areas without volcano, which suggests that Moho structures beneath volcano are different from general Moho structures in other areas. The crust thickness at two sides of Shenyang2Dunhua direction has a comparatively great change and its location is almost same as Dunhua-Mishan fault at near surface. Therefore, ( ) (2001DIA10003) ,,1963,,. E2mail ha. cn

2 2 : 353 Dunha2Mishan fault is a very important geological structure zone in the studied area. Keywords Volcanic area, Receiver function, Moho, S wave velocity,low velocity anomaly 1 ( ),, ( 1).,,,, [1,2 ]., 600 km [3 ].,,, 20, M L > [4 ] , ,,. ( ) ,. [5,6 ], km, 6198kmΠs, kmΠs [7 ]., 8 30km,, 2 6km,, [8 ] km, 30km [9 ]. 30km, [10 ]., Nong an2harbin fault ; Yitong2Yilan fault ; Dunhua2Mishan fault ; Yalujiang2Chunyang fault 1 Fig. 1 Geological survey and location of seismic stations in Changbaishan2Jingpohu area

3 354 (Chinese J. Geophys. ) 48, P S,,. P [10 14 ]. 2 ( 1) , 1, 53., Guralp 3T Ref Tek , 8, 3 18, DAS , ; P 20s, 200s P, ;,, 215, 1Hz, ; km.,,. [11 ] Wiener,.,, Randall.,, 1 2km,P V P S V S V P = 1173V S, = 0132V P , S., S, S. 2 (a c) 18 S. 2 (d,e) 14 S. J08,J14 C01, S. 3a 18, 3b 14.,,. S, S 413kmΠs, ( 2) S 1 C02 C03,, S. C03 S, 10km, S 312kmΠs, 20 30km, 10km. C02 S, 10km, C03,.., 8km, 10km, 30km, 50km. 15km,,

4 2 : (a,b,c) (d,e) S V S S, Z, 11 Fig. 2 12D S wave velocity structures beneath Changbaishan(a,b,c) and Jingbohu(d,e) seismic network from receiver function inversion [8 ].. 1,J01 J07, 5 10km. J09 J16. J01 J07 S,J01,J02,J05,J07 V S is S2wave velocities and Z is depth,for station positions see Fig km, kmΠs,.,,,. 30km [10 ].

5 356 (Chinese J. Geophys. ) 48

6 2 : 357, 30km, 30km. J09 J16 J13,J km,., Z = 15km, C03 S 311kmΠs, S ( kmΠs ), S 313kmΠs, J09 J16 S. Z = 30km, S kmΠs, ; S kmΠs, J09 J16 S kmΠs,,. Z = 40km, S 414kmΠs, 413kmΠs,. S, 10km, 30km,. 2, S S, S S., S., 2 C08,C14,C15,C18,..,, S, S km( 2 (a c) ), km,. ( 2 (d,e) ), C02 38km,C03 39km,. C11,C12,C13,C16 C km, 33 36km,. C11,C12,C13, C16 C18 ( 1),,. 1 L1 L2, Π, L1, 31km, 38km, 33km. L2 3115km,, 3415km [8 ]. 1,,C08,C02,C03,C06 L1, C11,C18,C07,C19 L2. 2, C08,C02,C03,C06 32,39,40km 34km. C11,C18,C07,C19 32,33,34km 35km. Π L1 L2,.,,S. :,,.,,, S, S, S,, 32 33km,

7 358 (Chinese J. Geophys. ) km,. 39km, 39 40km,. S,,. 10km, Π, V P ΠV S [8 ]. 10km [9 ].. S [15 ], V P ΠV S [16 ],, [8 ] km,. (2001DIA1003).,,!. (References) [ 1 ],,. NE. :M2SGT.. :, Zhang Y, Wang X K, Sui W G. Sinistral movement of northeast2 trending faults in northeast China. In : M2SGT Geological Group eds. Geological Study on Lithosphere Structure and History within Manzhouli2Suifenhe Geoscience Transect in China ( in Chinese ). Beijing : Geological Publishing House, [ 2 ].. :,1999 Liu J Q. China Volcano ( in Chinese). Beijing : Science Press, 1999 [ 3 ],.., 1983,26 (4) : Zhang L M, Tang X M. The underthrusting movement of the Western Pacific Plate and the deep focus earthquake zone of the Northeast China. Chinese J. Geophys. (in Chinese),1983, 26(4) : [ 4 ].., 1996,26 (3) : Fu W Z. Deep earthquakes in Northeast China and their tectonic significance. The Journal of Changchun Geological College ( in Chinese), 1996,26 (4) : [ 5 ],,..,1992,35(5) : Liu R X, Li J T, Wei H Q, et al. Vocano at Tianchi Lake, Chanbaishan MT. modern volcano with potential danger of eruption. Chinese J. Geophys. (in Chinese), 1992,35(5) : [ 6 ],,.., 1996,17 (4) : 2 11 Liu R X, Li J T, Tang J, et al. Progress of the study on Tianchi Volcano, Changbaishan. Seismological and Geomagnetic Observation and Research (in Chinese),1996, 17(4) :2 11 [ 7 ],,.. :,1998 Zhang Y X, Sun Y S, Zhang X Z, et al. China Manzhouli2Suifenhe Geo2Section. Beijing : Geological Publishing House, 1998 [ 8 ],,..,2002,24 (2) : Zhang X K, Zhang C K, Zhao J R, et al. Deep seismic sounding investigation into deep structure of the magma system in Changbaishan Tianchi volcanic region. Acta Seismologic Sinica (in Chinese), 2002,24 (2) : [ 9 ],,..,1997,19 (2) : Tang J, Liu T S, Jiang Z, et al. Preliminary observation of the Tianchi volcano area in Changbaishan Mountain by MT method. Seismology and Geology (in Chinese), 1997,19(2) : [10],,..,2001, 23(2) : Zhu R X, Fu W Z, Meng L S, et al. Preliminary study on electric in the Jingbohu volcano area of Heilongjiang province. Seismology and Geology (in Chinese), 2001,23 (2) : [11],.., 1998,41 (5) : Wu Q J, Zeng R S. The crustal structure of Qinghai2Xizhang Plateau inferred from broad teleseismic waveform. Chinese J. Geophys. (in Chinese), 1998, 41(5) : [12] Dueker K G, Sheehan A F. Mantle discontinuity structure beneath the Colorado Rocky Mountains and High plains. J. Geophys. Res., 1998, 103 : [13] Ai Yinshuang, Zheng Tianyu, Xu Weiwei, et al. A complex 660km discontinuity beneath northest China. Earth and Planetary Science Letters, 2003, 212 : [14] Ramesh D S, Kind R, Yuan X. Receiver function analysis of the North American crust and upper mantle. Geophys. J. Int., 2002, 150 : [15] Fountain D M, Christensen M I. Composition of the continental crust and upper mantal : a review. Geol. Soc. Amer. Bull, 1989, 172 : [16] O Connell R J, Budiansky B. Seismic velocities in dry and saturated cracked solids. J. Geophys. Res., 1974, 79 :