Deep Seismic Imaging of the Offshore Sector of the Campi Flegrei Caldera to Complement an Amphibic ICDP/IODP Drilling Initiative

Campi Flegrei火山区属于世界上最活跃的火山系统。该地区最明显的火山特征是半淹没的、准圆形的Campi Flegrei破火山口。它仍然是一个争论中的破火山口的形成是否只与一个熔结凝灰岩喷发，即，那不勒斯黄色凝灰岩（NYT）喷发在15万年，或者如果它是一个嵌套的破火山口系统有关的NYT和坎帕尼亚火山灰岩喷发在39万年。最后一次火山爆发发生在公元1538年的Monte Nuovo，经过3500年的平静。在过去的几十年里，Campi Flegrei破火山口的特点是短期的动荡，涉及相当大的地面变形（隆起和下沉数米），地震活动和温度升高的火山口。此外，在破火山口的中心部分可以观察到长期的变形，在几千年内上升了几十米。长期和短期的隆起都可以被解释为火山爆发的前兆，因此对未来的火山爆发表示高度关注，这将使生活在火山区周围的150多万人面临极端的火山风险。为了更好地了解这种动荡机制并正确评估喷发危险，坎皮弗莱格雷火山区在综合社区发展方案和综合海洋发展方案中采用了联合科学钻探方法。2008年，在DFG部分资助的德意考察期间，获得了高分辨率多道地震数据，以支持陆上和海上钻井活动。地震数据提供了一个洞察Campi Flegrei破火山口的演变，因为纽约时报爆发，并已在DFG ICDP优先计划的一个正在进行的项目的框架内解释。尽管在海底最深处300 m处的数据质量非常出色，但信号穿透不足以达到ICDP/IODP钻探活动所需的深度（约2 km）。在本提议的范围内，计划于2015年进行另一次考察，在此期间将部署一个低频地震系统，以实现信号穿透到拟议的综合社区开发方案/综合海洋开发方案钻探地点的目标深度。该待采集的地震数据集可作为最近完成的陆上ICDP钻井与波佐利湾和那不勒斯湾拟议IODP钻井地点之间的相关性的基础，以便绘制研究区域的大尺度图像。最终，这些数据将用于准备更新的海洋钻探活动。此外，即将获得的深穿透地震数据将是对现有高分辨率地震数据的最佳补充。这两个数据集的联合解释将提供尚未存在的见解Campi Flegrei破火山口的发展，包括那不勒斯黄色凝灰岩喷发前的时间跨度。

The Campi Flegrei Volcanic District belongs to the worlds most active volcanic systems. The most pronounced volcanic feature in that area is the half-submerged, quasi-circular Campi Flegrei caldera. It is still under debate whether the caldera formation was related to only one ignimbritic eruption namely, the Neapolitan Yellow Tuff (NYT) eruption at 15 ka, or if it is a nested-caldera system related to the NYT and the Campanian Ignimbrite eruption at 39 ka. The last volcanic eruption occurred in 1538 AD at the Monte Nuovo after 3500 years of quiescence. In the last decades, the Campi Flegrei caldera has been characterized by short-term episodes of unrest involving considerable ground deformation (uplift and subsidence of several meters), seismicity and increased temperature at fumaroles. Furthermore, long-term deformation can be observed in the central part of the caldera with uplift rates of several tens of meters within a few thousand years. Both long-term and short term uplift could be interpreted as eruption precursor, thereby posing high-concern for a future eruption, which would expose more than 1.5 million people living in the surroundings of the volcanic district to extreme volcanic risks. In order to improve the understanding of such unrest mechanisms and to correctly assess eruption hazards, the Campi Flegrei Volcanic District became subject to a joint approach for scientific drilling in the ICDP and IODP programmes. During a partially DFG funded, German-Italian expedition in 2008, high-resolution multi-channel seismic data were acquired to support the onshore and offshore drilling campaigns. The seismic data provide an insight into the evolution of the Campi Flegrei caldera since the NYT eruption and have been interpreted within the framework of an ongoing project in the DFG ICDP Priority Programme. Despite outstanding data quality of the uppermost 300 m below the seafloor, the signal penetration is not sufficient to achieve the required depths (~2 km) of the ICDP/IODP drilling campaigns. In the context of the present proposal another expedition is planned for 2015, during which a low-frequency seismic system shall be deployed in order to achieve signal penetration down to the target depth of the proposed ICDP/IODP drill sites. This to-be acquired seismic dataset may serve as a basis for the correlation of the recently completed onland ICDP drilling and proposed IODP drill sites in the Gulf of Pozzuoli and Naples Bay in order to develop a large scale picture of the study area. Eventually, the data shall be used to prepare an updated marine drilling campaign. Furthermore, the to-be acquired deep-penetrating seismic data would form an optimal complement to the already existing high-resolution seismic data. A joint interpretation of both datasets would provide not yet existing insights into the development of the Campi Flegrei caldera, including the time span before the Neapolitan Yellow Tuff eruption.