Geodetic modelling has become an established procedure to interpret the dynamics of active volcanic plumbing systems and magma transfer within the crust. Most established geodetic models implemented for inverting geodetic data share similar physical assumptions: (1) the Earth's crust is modelled as an infinite, homogeneous elastic half-space with a flat surface, (2) there is no anisotropic horizontal stress to simulate tectonic stresses, (3) the source boundary conditions are kinematic, i.e. they account for an instantaneous inflation or deflation of the source. Field and geophysical observations, however, provide evidence that significant inelastic shear deformation of the host rock can accommodate the propagation of dykes and sills. We show that inelastic processes accommodating the emplacement of dykes in the brittle crust have large implications for dyke-induced surface deformation patterns. We present two quantitative laboratory experiments of dyke emplacement, during which the syn-emplacement surface deformation is monitored. In one experiment, the host material is elastic gelatine, whereas in the other experiment the host material is cohesive Coulomb, plastic silica flour. Even if both experiments produce sub-vertical dykes of similar shapes, their emplacement mechanisms and their associated surface deformation strongly differ. In the gelatine experiment, the dyke propagates as a tensile fracture in a dominantly elastic host, and the surface deformation exhibits two uplifting bulges separated by a trough parallel to, and above the apex of, the underlying dyke. Conversely, in the silica flour experiment, the dyke propagates as viscous indenter through a dominantly plastic host, and the surface deformation exhibits a single uplifting area that narrows through time. The comparison of our experiments shows that (1) plastic deformation (e.g., shear failure, compaction) of the host has large effects on dyke-induced surface deformation patterns and needs to be considered in geodetic models, and (2) dyke emplacement mechanisms matter in geodetic modelling, strongly suggesting that commonly used kinematic geodetic models such as the opening rectangular dislocation model (Okada 1985) are limited for revealing the physics and dynamics of volcano plumbing systems. Finally, our silica flour experiment shows that pure uplift geodetic signals can result from the emplacement of a dyke emplaced as viscous indenter, whereas such signals are commonly modelled using geodetic models of inflating spherical/elliptical or horizontal planar source. Our experiments call for the design of new geodetic models that account, even partly, for the plastic deformation component of the Earth's brittle crust.

大地测量模型已经成为解释活动火山管道系统动力学和地壳内岩浆转移的既定程序。为反转大地测量数据而实施的大多数已建立的大地测量模型都具有相似的物理假设：（1）地壳被建模为具有平坦表面的无限均匀的弹性半空间，（2）没有各向异性的水平应力来模拟构造应力， （3）源边界条件是运动学的，即它们导致了源头的瞬时膨胀或收缩。然而，现场和地球物理观测提供了证据，表明母岩的显着非弹性剪切变形可以适应堤坝和基石的传播。我们表明，适应堤在脆性地壳中的位置的非弹性过程对堤引起的表面变形模式有很大的影响。我们提出堤防进驻的二轮量化实验室实验，在此期间，SYN监控安装表面变形。在一个实验中，主体材料是弹性明胶，而在另一个实验中，主体材料是粘性库仑塑料硅粉。即使两个实验都产生了相似形状的亚垂直堤坝，其位移机理和相关的表面变形也存在很大差异。在明胶实验中，堤坝在主要为弹性的宿主中以拉伸断裂的形式传播，并且表面变形显示出两个隆起的凸起，这些凸起由与下方堤坝的平行并在其顶点上方的一个波谷隔开。相反，在硅粉实验中，堤坝以粘性压头的形式通过占主导地位的塑料基质传播，表面变形表现出一个单一的隆起区域，该隆起区域随时间变窄。例如，剪切破坏，压实）对堤坝引起的表面变形模式有很大影响，需要在大地模型中加以考虑;（2）大堤模型在大地建模中很重要，这强烈暗示了常用的运动学大地模型例如开放的矩形位错模型（Okada 1985）对于揭示火山管道系统的物理和动力学是有限的。最后，我们的硅粉实验表明，纯隆起大地测量信号可能是由放置为粘性压头的堤坝引起的，而此类信号通常使用膨胀球形/椭圆形或水平平面源的大地测量模型来建模。我们的实验要求设计新的大地测量模型，该模型甚至部分要考虑到地球脆性地壳的塑性变形分量。