Abstract The Fucino lacustrine basin in central Italy is a large flat area mostly devoted to agriculture, with urbanization along the perimeter of the ancient lake. In 1915 a strong earthquake struck the area (Mw 7.0), producing large damages and geological effects, including surface faulting, ground failures and liquefaction. A channel excavated in the lacustrine sediments exposed ground failure, with dykes of fine-grained sediment that we interpret as the result of earthquake-induced liquefaction. We present the results of a multidisciplinary work aimed at characterizing in detail the geology of the buried stratigraphic succession, its susceptibility to liquefaction and the likely source of the fine-grained liquefied material. The succession down to 20 m deep is formed by fine-grained sediments younger than ~170–180 kyrs (mostly Late Pleistocene - Holocene), prevailingly silt or silt-clay mixtures. The geological field analysis indicates that the dykes are filled by prevailing silt, liquefied and transported by upward-directed flow of short duration, as for earthquake-induced liquefaction. Tilting and lateral spreading accompanied the process. The overall liquefaction potential derived from the “simplified methods” is high. Correlations of X-Ray Powder Diffraction mineralogy of samples from drilling cores with those from dykes allowed us to identify the most likely source layer filling dykes, corresponding to a silt layer at 7–8 m depths. This layer and the dykes lack illite and montmorillonite clay particles. These results contribute to improve studies of liquefactions in sediments that differ from typical liquefiable loose sands. They have also implications for microzonation studies. Most samples show grain-size curves that do not fit within the field of potentially liquefiable soils, suggesting that criteria based on grain-size can be poorly significant in seismic microzonation studies of recent (Late Pleistocene-Holocene) lacustrine, fine-grained successions.

中文翻译：

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晚第四纪细粒湖相序列（意大利富奇诺湖）中地震引起的液化特征：对微带研究的意义

摘要 意大利中部的富奇诺湖盆是一个大片平坦的地区，主要用于农业，沿古湖周边城市化。1915 年，该地区发生了强烈地震（Mw 7.0），造成了巨大的破坏和地质影响，包括地表断层、地面破坏和液化。在湖相沉积物中挖掘出的一条河道暴露了地面破坏，其中含有细粒沉积物的堤坝，我们将其解释为地震引起的液化的结果。我们展示了一项多学科工作的结果，旨在详细描述埋藏地层序列的地质特征、其液化敏感性以及细粒液化材料的可能来源。深达 20 m 的序列由小于 ~170-180 kyrs（主要是晚更新世 - 全新世）的细粒沉积物形成，主要是粉砂或粉砂粘土混合物。地质场分析表明，与地震引起的液化一样，堤坝被盛行的淤泥填满，液化并由短持续时间的向上流动输送。倾斜和横向扩展伴随着这个过程。源自“简化方法”的整体液化潜力很高。钻取岩心样品与岩脉样品的 X 射线粉末衍射矿物学的相关性使我们能够确定最可能的源层填充岩脉，对应于 7-8 m 深度的粉砂层。该层和岩脉缺乏伊利石和蒙脱石粘土颗粒。这些结果有助于改进对不同于典型可液化松散砂的沉积物液化的研究。它们对微区划研究也有影响。大多数样品显示的粒度曲线不适合潜在可液化土壤的领域，这表明基于粒度的标准在最近（晚更新世 - 全新世）湖泊细粒序列的地震微带研究中可能不太重要。