论文部分内容阅读
针对外媒报道长白山天池火山在近2年内有可能喷发的言论,在长白山天池火山区布测了一条长度约为103km的二维大地电磁测深观测剖面,对火山区深部电性结构进行探测研究.由于研究区内不明来源的电磁干扰非常强,对数据采用了远参考处理、Robust处理、Rhoplus分析、张量阻抗分解和基于一维层状介质电阻率与相位互算方法等先进处理技术,获取到一批在强干扰区质量较为可靠的电磁数据,利用数据计算分析了长白山天池火山区二维构造走向和感应矢量特征,采用NLCG二维反演技术对资料进行了二维反演解释,并将反演结果与前人探测结果进行了对比分析.探测结果表明:在天池火山口下方存在明显的直立型岩浆通道,岩浆通道在下方约5~8km位置形成关闭;在火山口下方往北方向附近,在埋深位置约7km深处存在一个明显的低阻异常体,电阻率小于10Ωm,且与岩浆通道对接,推测其可能是地表浅部发育的岩浆囊;在长白山山门附近C07-C09号测点之间和C04-C05号测点之间,在埋深约7~17km深处发现近直立型低阻带,低阻带与下方低阻体直接相连,推测低阻带内赋存有活动的岩浆;随着埋深的增加,从天池火山口南部约20km位置往北方向,在埋深13~30km之间壳内广泛发育明显的低阻异常体,推测其可能是活动的岩浆囊.反演结果与前人探测结果整体电性特征相似,但又局部不同.
In response to foreign media reports that the Changbaishan Tianchi volcano may have erupted within two years of remarks, a 2-D geomagnetic deep-sea observation section measuring about 103 km in length has been laid in the Tianchi volcano area of Changbai Mountain to probe the deep electrical structure of the volcano area Due to the extremely strong electromagnetic interference from unknown sources in the study area, advanced processing techniques such as far reference processing, Robust processing, Rhoplus analysis, tensor impedance decomposition, and based on the one-dimensional layered medium resistivity and phase mutual calculation method, A number of reliable electromagnetic data were obtained in the strong interference area. Based on the data, the two-dimensional tectonic evolution and the characteristics of the induction vector in the Tianchi volcano area of Changbai Mountain were analyzed. The NLCG 2D inversion technique was used to interpret the data in two dimensions. The results of the inversion are compared with those of the predecessors.The results show that there is obvious vertical type magmatism below the Tianchi caldera, and the magma channel is closed at about 5 ~ 8km below. In the lower part of the crater, There is an obvious low-resistivity anomaly in the depth of about 7km near the direction, the resistivity is less than 10Ωm, and it is connected with the magma channel, It is presumed that it may be a magma lacustrine with shallow surface. Near the Chang-Baishan Mountain Gate between C07-C09 and C04-C05, near-standing low-resistivity zone , The low-resistivity zone is directly connected with the low-resistivity body below, and it is presumed that there is active magma in the low-resistivity zone. With the increase of the depth, from about 20km to the north in the south of the Tianchi volcano and from 13km to 30km The apparent low-resistivity anomaly is widely developed in the intercalated shell, suggesting that it may be an active magma pouch. The inversion results are similar to the overall electrical characteristics of the previous detection results, but they are also partially different.