Several record-breaking precipitation events have struck the mountainous area of the Emilia–Romagna region (northern Apennines, Italy) over the last 10 years. As a consequence, severe geomorphological processes such as debris avalanches and debris flows, shallow landslides, and overbank flooding have affected the territory, causing severe damage to human-made structures. The unusual intensity of these phenomena prompted an investigation into their frequency in the past, beyond instrumental time. In the quest for an understanding of whether these phenomena are unprecedented in the region, peat bog and lake deposits were analyzed to infer the frequency of extreme precipitation events that may have occurred in the past. We present the results of a dedicated field campaign performed in summer 2017 at Lake Moo in the northern Apennines, a 0.15 km² peat bog located at an altitude of 1130 m a.s.l. During the extreme precipitation event of 13–14 September 2015, several debris flows generated by small streams affected the Lake Moo plain. In such a small drainage basin (<2 km²), high-density floods can be triggered only by high-intensity precipitation events. The sedimentary succession (ca. 13 m thick) was studied through the drilling of two cores and one trench. The sequence, characterized by clusters of coarse-grained alluvial deposits interbedded with organic-rich silty clays and peat layers, was analyzed by combining sedimentological, pollen, microanthracological and pedological data with radiocarbon dating (AMS ¹⁴C) in an innovative multidisciplinary approach for this area. Original data acquired during the field campaign were also correlated with other specific paleoclimatic proxies available in the literature for the northern Apennines area. We discover that the increase in extreme paleoflooding, associated with coarse-grained deposits similar to the ones observed recently, correlates well with the warm phases of the Holocene Thermal Maximum and with the ongoing warming trend observed that started at the beginning of the last century.

中文翻译：

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过去9000年的多学科数据显示，北部亚平宁山脉（意大利）的高强度降水变化

在过去的10年中，几次破纪录的降雨事件袭击了艾米利亚·罗马涅地区（意大利北部亚平宁山脉）的山区。结果，诸如雪崩和泥石流，浅层滑坡和堤岸泛滥等严重的地貌过程影响了该领土，对人造结构造成了严重破坏。这些现象的异常强度促使人们对过去超出工具时间的频率进行调查。为了了解这些现象在该地区是否是前所未有的，对泥炭沼泽和湖泊沉积物进行了分析，以推断过去可能发生的极端降水事件的发生频率。我们介绍了2017年夏季在亚平宁山脉北部长0.15公里的Moo湖上进行的一次专门野战的结果^2个泥炭沼泽，位于1130'mâasl的高度。在2015年9月13日至13日的极端降雨事件中，小溪流产生的几处泥石流影响了Moo湖平原。在这么小的流域（ < 2？km ²）中，高密度洪水只能由高强度降水事件触发。通过钻探两个岩心和一个沟槽研究了沉积层序（约13微米厚）。通过将沉积，花粉，微人类学和土壤学数据与放射性碳测年相结合（AMS ¹⁴ C），分析了该层序，其特征是粗粒冲积层与高有机质粉质粘土和泥炭层互层。），以创新的多学科方法来解决这一领域。在野战期间获得的原始数据也与北亚平宁山脉地区文献中可获得的其他特定古气候代理相关。我们发现，极端古洪水的增加与最近观测到的相似的粗粒沉积物相关，这与全新世热最大值的暖期以及上世纪初开始观察到的持续变暖趋势密切相关。