Large boulder deposits by tsunami waves along the Ionian coast of south-eastern Sicily (Italy)
Large boulder deposits by tsunami waves along the Ionian coast of south-eastern Sicily (Italy)
复制标题
西西里岛东南部爱奥尼亚海岸（意大利）海啸造成的巨石沉积
DOI：
10.1016/j.margeo.2006.12.005
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发表时间：
2007
期刊：
影响因子：
2.9
通讯作者：
L. Tortorici
中科院分区：
文献类型：
--
作者：
G. Scicchitano;C. Monaco;L. Tortorici
西西里东南部的爱奥尼亚海岸，奥古斯塔和锡拉库扎之间的城镇，其特点是异常的钙质巨石的出现。它们大多分布在海拔2-5米的大阶地上，沿着向大海倾斜。巨石的重量可达182吨，并以孤立的元件或由几个堆叠元件组成的小组排列。几个巨石显示生物结壳（serpulids，balanids，lithophaga）遍布其表面，这表明它们是从中亚沿岸带拖过来的。其他巨砾部分被生物结壳覆盖，并显示出形态特征（岩溶池，暴露的断裂面），表明它们是从中滨海区分离和分散的。对每一个巨石的直接观察（离海岸线的距离、大小和重量），加上对该地区风暴状况的统计分析，可以进行流体动力学估计，以核实海啸或风暴波是否是造成巨石脱离和迁移的原因，而海洋生物的放射性碳年龄测定则限制了时间。收集到的数据，与历史目录相比，表明在过去的1000年中，三个地震事件与当地的来源可能引发海啸波与巨石沉积发生在该地区。前两次地震可能是由1169年2月4日和1693年1月11日的地震引发的，这两次地震摧毁了西西里东南部。根据地质资料和数值模拟，孕震源可能位于卡塔尼亚和锡拉库扎之间的爱奥尼亚近海。第三次海啸是由1908年12月28日发生在墨西拿海峡的强烈地震引起的。
The Ionian coast of south-eastern Sicily, between the towns of Augusta and Siracusa, is characterized by the occurrence of anomalous calcareous boulders. They are mostly scattered along large terraces located 2–5 m above sea level, gently sloping towards the sea. Boulders are up to 182 t in weight and are arranged either in isolated elements or small groups composed of a few stacked elements. Several boulders show biogenic encrustations (serpulids, balanids, lithophaga) all over their surface which suggest that they were dragged from the mid-sublittoral zone. Other boulders are partially covered by biogenic encrustations and show morphological features (karstic pools, exposed fracture surfaces) suggesting that they were detached and scattered from the mid-supralittoral zone. Direct observations on each boulder (distance from the shoreline, size and weight), together with statistical analysis of the storm regime of the area, allowed to operate hydrodynamic estimations useful to verify if tsunami or storm waves were responsible for their detachment and transport, while radiocarbon age determinations on marine organisms constrained the timing. Collected data, compared to historical catalogues, suggest that in the last 1000 years three seismic events with local sources could have triggered tsunami waves associated with the boulder deposits occurring in the area. The first two were probably triggered by the earthquakes of February 4, 1169 and January 11, 1693 which destroyed south-eastern Sicily. According to geological data and numerical modelling, the seismogenic source could be located in the Ionian offshore between Catania and Siracusa. The third tsunami was generated by the strong earthquake which took place in the Strait of Messina on December 28, 1908.