Subaqueous Pyroclastic Deposits from Tambora and Krakatau Volcanoes, Indonesia

在印度尼西亚坦博拉大爆发期间，1815年事件期间，可能有多达30千米的火山碎屑流进入海洋。同样，在1883年的事件中，在喀拉喀托火山形成了厚达30米、长达15公里的火山碎屑流或泥石流。人们对水下火山碎屑流与海洋相互作用的性质知之甚少，但对于火山成因海啸的相互竞争的模型和共同褐煤灰烬的形成来说，这是至关重要的。PIS将研究坦博拉(1815年)和克拉卡托(1883年)的海底沉积物，方法是利用坦博拉地区现有的一套活塞和重力岩心，并从克拉卡托周围的浅海收集新的岩心。这项研究的结果将用于1)检验坦博拉和喀拉喀托火山喷发期间产生海啸和共生褐煤火山灰的现有模型，2)开发火山碎屑流与海水相互作用的一般模型，以及3)描述由这种相互作用形成的水下沉积的性质。这些结果对于理解这些事件的喷发过程和提供可应用于地质记录中古代汇聚边缘序列的现代火山碎屑沉积模拟将具有重要意义。该项目是与国家地理学会共同资助的。

During the great explosive eruptions of Tambora in Indonesia as up to 30 km3 of pyroclastic flows may have entered the ocean during the 1815 event. Similarly, pyroclastic or debris flows of unknown character formed up to 30 m thick submarine deposits up to 15km from the Krakatau volcano in the 1883 event. The nature of the interaction between subaerial pyroclastic flows and the sea is poorly understood but is critical to competing models of volcanogenic tsunami generation and of the formation of co-ignimbrite ash. The PIs will study the submarine deposits from tambora (1815) and Krakatau (1883) by using a suite of existing piston and gravity cores from the Tambora area and by collection of new cores from the shallow seas around Krakatau. The results of the study will be used to 1) test existing models for the generation of tsunamis and co-ignimbrite ash fall during the Tambora and Krakatau eruptions, 2) develop general models for the interaction of pyroclastic flows and seawater, and 3) characterize the nature of subaqueous deposits formed by such interactions. These results will be significant in terms of understanding the eruptive processes of these events and providing modern analogues of volcaniclastic sedimentation that can be applied to ancient convergent margin sequences in the geologic record. The project is being co- funded with National Geographic Society.