TOMODEC. High resolution seismic tomography of Deception Island (Antarctica), and modelling of seismo-volcanic sources. MAGNETIC DATA

In January 2005 a multi-parametric international experiment was conducted that encompassed both Deception Island and its surrounding waters. This experiment used as main platforms the Spanish Oceanographic vessel 'Hesperides', the Spanish Scientific Antarctic base 'Gabriel de Castilla' at Deception Island and four temporary camps deployed on the volcanic island. This experiment allowed us to record active seismic signals on a large network of seismic stations that were deployed both on land and on the seafloor. In addition other geophysical data were acquired, such as: bathymetric high precision multi-beam data, and gravimetric and magnetic profiles.The magnetometer SeaSPY is an acquisition system from the Company Marine Magnetics with a very sensitive and omnidirectional Overhauser sensor. This sensor allows measurement of the total magnetic field and was stable in time during the survey period. This system has a high-precision clock (1 ppm) and it can be synchronized with the onboard GPS clock. This equipment is thermally stabilized permitting it to operate in all type of sea waters, including Antarctic waters, and due to its design there are no heading errors. In table 4 we summarize its technical characteristics. The magnetometer was used during the first phase of shooting outside of Post Foster. However, its 200 m long tow cable precluded its use inside the Deception Island inner bay.

2005年1月，一项多参数国际实验顺利开展，实验覆盖范围涵盖欺骗岛（Deception Island）及其周边海域。本次实验以西班牙海洋考察船‘赫斯佩里得斯号’（Hesperides）、位于欺骗岛的西班牙南极科学考察站‘加夫列尔·德·卡斯蒂利亚站’（Gabriel de Castilla），以及部署在这座火山岛上的4座临时营地作为主要观测平台。实验依托覆盖陆地与海底的大型地震台站网络，成功记录到主动地震信号。此外，本次实验还采集了多类地球物理数据，包括高精度多波束测深数据、重力与磁测剖面。磁力仪SeaSPY是海洋磁学公司（Marine Magnetics）研发的采集系统，搭载高灵敏度全向Overhauser传感器。该传感器可实现总磁场强度的精准测量，且在整个勘测周期内具备优异的时间稳定性。该系统配备高精度时钟（精度为1 ppm），可与船载GPS时钟实现同步。设备内置热稳定系统，可在包括南极海域在内的各类海洋环境中正常作业，同时凭借其独特设计，不存在航向误差问题。我们在表4中总结了该系统的技术参数。该磁力仪曾在波斯特福斯特（Post Foster）外海域的第一阶段震源放炮作业中投入使用，但因其配备200米长的拖曳电缆，无法在欺骗岛内部海湾内开展作业。