Interpretation of long-offset transient electromagnetic data from Mount Merapi, Indonesia, using a three-dimensional optimization approach
Interpretation of long-offset transient electromagnetic data from Mount Merapi, Indonesia, using a three-dimensional optimization approach
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使用三维优化方法解释印度尼西亚默拉皮火山的长偏移距瞬变电磁数据
DOI：
10.1029/2004jb003206
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
B. Tezkan
中科院分区：
文献类型：
--
作者：
M. Commer;S. Helwig;A. Hördt;B. Tezkan
在1998年、2000年和2001年，在中爪哇的默拉皮活火山进行了长偏移距瞬变电磁（LOTEM）勘测。测量研究了火山建筑物的导电性结构。我们感兴趣的区域，这是低于首脑会议和上侧翼，进行了调查，使用水平和垂直磁场时间导数数据从七个发射机-接收器设置。由于地形和三维（3-D）地下结构，使用3-D解释。该方法通过对数据进行稳定的最小二乘联合反演来优化三维模型的少数参数，从而提供足够的分辨率能力。合理的数据拟合实现了一个非水平分层模型，具有非常导电的地下室深度为1.5公里。虽然也考虑了热液蚀变，我们尝试性地解释了高电导率的水溶液相对较高的盐含量。一个大的岩浆体或一个小的浅表水库下面的默拉皮的中央火山复合体，如其他作者所讨论的，不能解决的LOTEM数据。
In the years 1998, 2000, and 2001, long-offset transient electromagnetic (LOTEM) surveys were carried out at the active volcano Merapi in Central Java. The measurements investigated the conductivity structure of the volcanic edifice. Our area of interest, which is below the summit and the upper flanks, was investigated using horizontal and vertical magnetic field time derivative data from seven transmitter-receiver setups. Because of topography and a three-dimensional (3-D) underground structure, a 3-D interpretation is used. The method optimizes few parameters of a 3-D model by a stable least squares joint inversion of the data, providing sufficient resolution capability. Reasonable data fits are achieved with a nonhorizontally layered model featuring a very conductive basement below depths of 1.5 km. While hydrothermal alteration is also considered, we tentatively explain the high conductivities by aqueous solutions with relatively high salt contents. A large magma body or a small superficial reservoir below Merapi's central volcanic complex, as discussed by other authors, cannot be resolved by the LOTEM data.