The monumental tumulus Yığma Tepe is an important part of the cityscape of the ancient city of Pergamon. The tumulus construction is estimated in the Hellenistic period, the internal structure and exact purpose have been unknown so far. Its height of 32 m and diameter of 158 m make the deep interior of the tumulus practically inaccessible for excavations. Therefore, we applied a combination of geophysical measurements and archaeological sondages to explore the structure of the Yığma Tepe. The investigations centre on P‐wave refraction soundings. They were carried out to clarify the stratigraphic structure and soil composition as a prerequisite for a better understanding of construction techniques, building history and soil deposition. Interactive seismic raytracing, traveltime tomography and visco‐elastic forward modelling were applied to derive a three‐dimensional seismic velocity model, which was validated by excavations and soil analysis, historical records and additional geoelectric measurements. Our results reveal that the tumulus is composed of three layers, each about 10 m thick, separated by first‐order seismic discontinuities which were locally verified. These layers form a stack of conical disks, the interfaces of which define two internal plateaus. The analysis of soil samples showed that the seismic velocity increase at the interfaces is likely to be caused by anthropogenic compaction applied to soils showing increased fractions of silt and clay. By combining topographic data with results from seismic and geoelectric sounding on the tumulus, the surrounding trench and the unaltered surrounding area, we show that the tumulus was built almost completely from the surrounding soils and that 17% of its original volume was displaced by destruction and erosion. Based on this mass balance the strongly destroyed and eroded original surface of the tumulus and its surrounding trench is reconstructed.

中文翻译：

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佩尔加蒙YığmaTepe：通过地震折射测量得到的巨大古墓的地层构造

巨大的坟墓YığmaTepe是佩加蒙古城城市景观的重要组成部分。这种古坟的构造是在古希腊时期估计的，到目前为止其内部结构和确切目的尚不清楚。它的高度为32 m，直径为158 m，使得挖掘工作几乎无法进入到古墓的深处。因此，我们结合了地球物理测量和考古学探测来探索YığmaTepe的结构。研究集中在P波折射测深上。进行这些研究是为了阐明地层结构和土壤成分，这是更好地了解施工技术，施工历史和土壤沉积的前提。交互式地震射线追踪 应用行进时间层析成像和粘弹性正演模型得出三维地震速度模型，该模型通过挖掘和土壤分析，历史记录以及其他地电测量得到了验证。我们的结果表明，古卷由三层组成，每层约10 m厚，被一阶地震不连续性隔开，这些地震不连续性已在当地得到验证。这些层形成一堆锥形盘，其接口定义了两个内部平台。对土壤样品的分析表明，界面处的地震速度增加可能是由于施加于土壤的人为压实作用所致，表明泥沙和粘土的含量增加。通过将地形数据与古坟上的地震和地电探测结果相结合，在周围的沟渠和未改变的周围区域中，我们发现古坟几乎完全是由周围的土壤建造而成，其原始体积的17％被破坏和侵蚀所取代。基于这种质量平衡，重建了强烈破坏和侵蚀的原始肿瘤表面及其周围的沟渠。