Abstract A major seismovolcanic crisis has afflicted the islands of Mayotte, Comoros Archipelago, since May 2018, although the origin is debated. Magnetotellurics (MT), which is sensitive to hydrothermal and/or magmatic fluids and can map the subsurface electrical resistivity structure, can provide insight by revealing the internal structure of the volcanic system. In this paper, we report the results of a preliminary land and shallow marine MT survey performed on and offshore the island nearest the crisis. The 3D inversion-derived electrical resistivity model suggests that the island is underlain by a shallow ~500-m-thick conductive layer atop a deeper, more resistive layer, possibly associated with a high-temperature geothermal system. At depths of ~15 km, the resistivity drops by almost two orders of magnitude, possibly due to partial melting. Further petrophysical and geophysical studies are underway for confirmation and to map the geometry and evolution of the volcanic system.

中文翻译：

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用大地电磁测深绘制火山系统的几何形状：2018-2019 年马约特地震火山危机期间进行的陆地和海洋大地电磁勘测的结果

摘要 自 2018 年 5 月以来，一场严重的地震火山危机困扰着科摩罗群岛的马约特岛，尽管其起源尚存争议。大地电磁 (MT) 对热液和/或岩浆流体敏感，可以绘制地下电阻率结构图，可以通过揭示火山系统的内部结构来提供洞察力。在本文中，我们报告了在离危机最近的岛屿上和近海进行的初步陆地和浅海 MT 调查的结果。3D 反演得出的电阻率模型表明，该岛的下方是一层约 500 米厚的浅导电层，位于更深、电阻更大的层之上，可能与高温地热系统有关。在约 15 公里的深度，电阻率下降了几乎两个数量级，可能是由于部分熔化。