A combined imaging and modelling approach to understand magmatic systems across the SE Asia-Australia collision zone

欧亚板块南部与澳大利亚之间的碰撞带是冈瓦纳大陆派生的板块、俯冲板块和碰撞岩石圈块体的复杂集合体。最近，我们已经取得了显着的决议深区域俯冲的P波和S波，特别是在班达海。最近在整个区域部署的地震阵列现在可以提高整个碰撞区的分辨率。尽管如此，衰减仍然是一个重要的障碍，一个可靠的岩石圈尺度，全波形反演的地区。衰减层析成像可以填补这一空白，并提供更高的灵敏度和照明岩石圈过程，特别是那些导致岩浆作用。本提案的第一个目标是对导致东南亚-澳大利亚碰撞带火山活动的岩石圈尺度衰减结构进行成像，提供（1）区域尺度基准，以改进区域尺度的全波形成像，以及（2）改进连接地幔结构和岩浆中心的岩石圈结构的成像。为此，该项目将采用现有的速度层析成像机器学习框架进行波形分析，并将三维直接波衰减成像与地壳吸收和散射映射结合起来。最终结果将与现有的层析成像模型和合作伙伴提供的数据一起用于第二个目标：对（1）整个碰撞区和（2）供给阿贡火山的岩浆系统进行区域尺度粘（弹）塑性建模，一旦结合到基于伴随的反演方案中。使用衍生的高分辨率和力学一致的结构模型，最终交付的成果将允许更好地定量评估碰撞区的机制，深入了解岩浆和流体从俯冲到地表的迁移。

The zone of collision between the southern region of the Eurasian plate and Australia is a complex aggregate of Gondwana-derived terranes, subducting plates, and a colliding lithospheric block. Recently we have achieved significant resolution on the deep regional subduction for both P- and S-waves, especially across the Banda Sea. Seismic arrays recently deployed across the region now allow to increase resolution across the entire collision zone. Still, attenuation remains an important obstacle for a reliable lithospheric-scale, full-waveform-inversion of the area. Attenuation tomography can both fill this gap and offer improved sensitivity and illumination on lithospheric processes, especially those leading to magmatism. The first objective of this proposal is to image the lithospheric-scale attenuation structures leading to volcanism across the SE Asia – Australia collision zone, providing (1) a regional-scale benchmark to improve full-waveform imaging at regional scale and (2) improved imaging of the lithospheric structures connecting mantle structures to magmatic centres. To do so, the project will adapt an existent machine-learning framework for velocity tomography to waveform analysis, and will join 3D direct-wave-attenuation imaging with crustal absorption and scattering mapping. The end-results will be used together with existent tomographic models and available data from partners for the second objective: performing regional-scale visco(elasto)plastic modelling for (1) the entire collision zone and (2) the magmatic systems feeding Agung volcano, once combined to an adjoint-based inversion scheme. Using the derived high-resolution and mechanically-consistent structural models, the final deliverables will allow a better quantitative evaluation of the mechanisms in play in the zone of collision, giving insight into magma and fluid migration from subduction to surface.