Seismicity and active tectonics at Coloumbo Reef (Aegean Sea, Greece): Monitoring an active volcano at Santorini Volcanic Center using a temporary seismic network
Seismicity and active tectonics at Coloumbo Reef (Aegean Sea, Greece): Monitoring an active volcano at Santorini Volcanic Center using a temporary seismic network
复制标题
DOI：
10.1016/j.tecto.2008.11.005
复制
发表时间：
2009-02-20
期刊：
影响因子：
2.9
通讯作者：
Meier, T.
中科院分区：
文献类型：
--
作者：
Dimitriadis, I.;Karagianni, E.;Meier, T.
圣托里尼岛的火山中心是爱琴海南部火山弧中最活跃的火山。为监测和研究2003年3月至2003年9月期间圣托里尼火山中心广大地区的地震火山活动，部署了由14个便携式宽带地震台组成的密集地震台阵。来自邻近较大规模临时台网的额外记录也用于两个台阵记录的240多次地震的重新定位。结果表明，圣托里尼火山中心的地震活动与更广泛的南爱琴海地区的构造体制以及火山过程密切相关。震中主群位于科伦博礁，这是圣托里尼群岛火山系的一座海底火山。一个较小的事件群位于Anydros岛附近，沿NE-西南方向排列，几乎沿着研究区域的主要构造特征--圣托里尼-阿莫尔戈斯断裂带延伸。相比之下，主要的圣托里尼岛火山口的特点是几乎完全没有地震活动。这一对比与最近的火山学和海洋学研究非常一致，与圣托里尼火山对应的低水平活动相比，科隆博火山中心显示出强烈的高温热液活动。高分辨率的震源重新定位清楚地展示了科伦博礁的火山海底结构，表明主要地震活动位于一个非常狭窄的垂直柱体内，主要位于6至9公里深。最佳位置事件的震源机制表明，Coloumbo礁的震源机制与“Kameni-Coloumbo断裂带”有关，该断裂带相当于主要的ENE-WSW Santorini-Amorgos断裂带的西端。科隆博礁现有断层面解的应力-张量反演，以及东北圣托里尼(科隆博半岛)已有的新构造断裂信息表明，东北圣托里尼-科隆博断裂属于单一断裂系统，局部应力场相对于爱琴海南部NNW-SSE区域延伸场旋转约30度。观测到的断层面解的变化表明，Coloumbo海底火山区的局部条件控制了观测到的断裂模式。(C)2008爱思唯尔B.V.保留所有权利。
The volcanic center of Santorini Island is the most active volcano of the southern Aegean volcanic arc. A dense seismic array consisting of fourteen portable broadband seismological stations has been deployed in order to monitor and study the seismo-volcanic activity at the broader area of the Santorini volcanic center between March 2003 and September 2003. Additional recordings from a neighbouring larger scale temporary network (CYCNET) were also used for the relocation of more than 240 earthquakes recorded by both arrays. A double-difference relocation technique was used, in order to obtain optimal focal parameters for the best-constrained earthquakes.The results indicate that the seismic activity of the Santorini volcanic center is strongly associated with the tectonic regime of the broader Southern Aegean Sea area as well as with the volcanic processes. The main cluster of the epicenters is located at the Coloumbo Reef, a submarine volcano of the volcanic system of Santorini Islands. A smaller cluster of events is located near the Anydros Islet, aligned in a NE-SW direction, running almost along the main tectonic feature of the area under study, the Santorini-Amorgos Fault Zone. In contrast, the main Santorini Island caldera is characterized by the almost complete absence of seismicity. This contrast is in very good agreement with recent volcanological and marine studies, with the Coloumbo volcanic center showing an intense high-temperature hydrothermal activity, in comparison to the corresponding low-level activity of the Santorini caldera.The high-resolution hypocentral relocations present a clear view of the volcanic submarine structure at the Coloumbo Reef, showing that the main seismic activity is located within a very narrow vertical column, mainly at depths between 6 and 9 km. The focal mechanisms of the best-located events show that the cluster at the Coloumbo Reef is associated with the "Kameni-Coloumbo Fracture Zone", which corresponds to the western termination of the major ENE-WSW Santorini-Amorgos Fault Zone. Stress-tensor inversion of the available fault plane solutions from Coloumbo Reef, as well as existing neotectonic fault information from NE Santorini (Coloumbo peninsula), suggests that the NE Santorini-Coloumbo faults belong to a single rupture system, with a similar to 30 degrees rotation of the local stress field with respect to the NNW-SSE regional extension field of the southern Aegean Sea. The observed change of the fault plane solutions shows that local conditions at the Coloumbo submarine volcano area control the observed faulting pattern. (C) 2008 Elsevier B.V. All rights reserved.