Approaching the seismogenic source of the Calabria 8 September 1905 earthquake: New geophysical, geological and biochemical data from the S. Eufemia Gulf (S Italy)
Approaching the seismogenic source of the Calabria 8 September 1905 earthquake: New geophysical, geological and biochemical data from the S. Eufemia Gulf (S Italy)
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接近 1905 年 9 月 8 日卡拉布里亚地震的震源：来自南欧菲米亚湾（意大利南部）的新地球物理、地质和生化数据
DOI：
10.1016/j.margeo.2013.06.016
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发表时间：
2013
期刊：
影响因子：
2.9
通讯作者：
L. Facchin
中科院分区：
文献类型：
--
作者：
M. Loreto;U. Fracassi;A. Franzo;P. Negro;Fabrizio Zgur;L. Facchin
认识重大历史地震的震源，特别是发生在近海的地震，是地中海和其他地区长期存在的问题。 1905 年 9 月 8 日夜间袭击卡拉布里亚西部（意大利南部）的破坏性地震（M ~ 7）就是一个这样的例子，不同的作者提出了一个地震源，但提出了明显不同的假设，但没有找到唯一的解决方案。为了对 1905 年地震发生的地壳体积有新的认识，并为与这一破坏性事件相关的震源寻求更可靠的解决方案，我们在南欧菲米亚湾（第勒尼安海东南部）内进行了一项有针对性的多学科调查，收集了地球物理数据、海洋学测量以及生物、化学和沉积样本。我们确定了影响南欧菲米亚湾沉积盆地的三个主要构造特征：1）a NE-SW 引人注目，约。 13公里长的正断层，这里命名为S. Eufemia断层； 2）WNW走向的多相断层系统； 3) 可能的东西向轮廓。其中，正断层显示出近期沉积物变形及其海底破裂所见证的活动证据，沿着海底破裂，局部发生了流体泄漏。浅层沉积物分析得出的特征与原核生物丰度和生物聚合碳含量的异常分布一致。过去 15 年文献中提出的众多地震源构成了卡拉布里亚西部这一地区的复合框架，我们根据 a) 新获取的数据集的地质证据和 b) 区域地震构造模型对其进行了测试。通过这样的评估，我们可以提出 NE-SW 走向的正断层是 1905 年地震最有可能的震源。将历史上的一场大地震重新评估为 1905 年地震，增强了卡拉布里亚西部的地震构造图景。通过对我们的数据以及 a) 陆地现场证据和 b) 地震模型的综合解释，可以进一步了解该地区并更好地限制震源的位置。
Recognizing the seismogenic source of major historical earthquakes, particularly when these have occurred offshore, is a long-standing issue across the Mediterranean Sea and elsewhere. The destructive earthquake (M ~ 7) that struck western Calabria (southern Italy) on the night of 8 September 1905 is one such case having various authors proposed a seismogenic source, with apparently diverse hypotheses and without achieving a unique solution. To gain novel insight into the crustal volume where the 1905 earthquake took place and to seek a more robust solution for the seismogenic source associated with this destructive event, we carried out a well-targeted multidisciplinary survey within the Gulf of S. Eufemia (SE Tyrrhenian Sea), collecting geophysical data, oceanographic measurements, and biological, chemical and sedimentary samples.We identified three main tectonic features affecting the sedimentary basin in the Gulf of S. Eufemia: 1) a NE-SW striking, ca. 13-km-long, normal fault, here named S. Eufemia Fault; 2) a WNW-striking polyphased fault system; and 3) a likely E-W trending lineament. Among these, the normal fault shows evidence of activity witnessed by the deformed recent sediments and by its seabed rupture along which, locally, fluid leakage occurs. Features in agreement with the anomalous distribution of prokaryotic abundance and biopolymeric C content, resulted from the shallow sediment analyses.The numerous seismogenic sources proposed in the literature during the past 15 yr make up a composite framework of this sector of western Calabria, that we tested against a) the geological evidence from the newly acquired dataset, and b) the regional seismotectonic models. Such assessment allows us to propose the NE-SW striking normal fault as the most probable candidate for the seismogenic source of the 1905 earthquake. Reappraising a major historical earthquake as the 1905 one enhances the seismotectonic picture of western Calabria. Further understanding of the region and better constraining the location of the seismogenic source may be attained through integrated interpretation of our data together with a) on-land field evidence, and b) seismological modeling.