SUMMARY Lusi is a sediment-hosted hydrothermal system located near Sidoarjo in Central Java, Indonesia, and has erupted continuously since May 2006. This mud eruption extends over a surface of ∼7 km2, and is framed by high containment dams. The present study investigates the geometry of the subsurface structures using a detailed gravimetric model to visualize in 3-D the Lusi system and surrounding lithologies. The obtained residual Bouguer anomaly map, simulated through geostatistical interpolation methods, supports the results of previous deformation studies. The negative gravity anomaly zones identified at Lusi are interpreted as fractured areas through which fluids can ascend towards the surface. A 3-D detailed geological model of the area was constructed with Geomodeller™ to highlight the main features. This model relies on the structures’ density contrasts, the interpreted residual Bouguer anomaly map, and geological data from previous authors. 3-D algorithms were used to calculate the gravity response of the model and validate it by inverse methods. The final output is a gravity constrained 3-D geological model of the Lusi mud edifice. These results provide essential details on the Lusi subsurface and may be useful for possible future geothermal resource exploitation and for the risk mitigation plans related to the maintenance of the man-made framing embankment.

中文翻译：

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通过重力分析对 Lusi（爪哇，印度尼西亚）泥浆大厦的构造洞察和 3-D 建模

总结 Lusi 是一个位于印度尼西亚中爪哇岛 Sidoarjo 附近的沉积物热液系统，自 2006 年 5 月以来一直在持续喷发。这次泥浆喷发覆盖了约 7 km2 的表面，并由高防护坝围住。本研究使用详细的重力模型研究地下结构的几何形状，以 3-D 可视化 Lusi 系统和周围的岩性。通过地统计插值方法模拟获得的残余布格异常图支持先前变形研究的结果。Lusi 发现的负重力异常区被解释为流体可以通过其上升到地表的裂缝区域。使用 Geomodeller™ 构建了该地区的 3-D 详细地质模型，以突出主要特征。该模型依赖于结构的密度对比、解释的残余布格异常图以及前作者的地质数据。3-D算法被用来计算模型的重力响应，并通过反演方法对其进行验证。最终输出是一个受重力约束的 3-D 鲁斯泥大厦地质模型。这些结果提供了关于 Lusi 地下的基本细节，可能对未来可能的地热资源开发以及与人工框架路堤维护相关的风险缓解计划有用。最终输出是一个受重力约束的 3-D 鲁斯泥大厦地质模型。这些结果提供了关于 Lusi 地下的基本细节，可能对未来可能的地热资源开发以及与人工框架路堤维护相关的风险缓解计划有用。最终输出是一个受重力约束的 3-D 鲁斯泥大厦地质模型。这些结果提供了关于 Lusi 地下的基本细节，可能对未来可能的地热资源开发以及与人工框架路堤维护相关的风险缓解计划有用。