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Recent Macaronesian kinematics from GNSS ground displacement analysis
Studia Geophysica Et Geodaetica ( IF 0.9 ) Pub Date : 2021-01-08 , DOI: 10.1007/s11200-020-1122-x
Ignacio Barbero , Cristina Torrecillas , Raúl Páez , Gonçalo Prates , Manuel Berrocoso

Macaronesia is a complex oceanic region spanning three tectonic plates in the northeast Atlantic ocean. It is composed of four archipelagos, widely distributed and limited to the east by the Iberian Peninsula and north-western coast of Africa. This study aims to clarify recent Macaronesian kinematics from 19 GNSS stations located on the four archipelagos and the Iberian and African coastlines. The analysis is based on nearly 15 years of common data acquisition and aimed to detect new effects of intraplate tectonics or similar local/regional events consistent with calculated ground displacements. Evaluating the GNSS stations residual velocities relative to those expected from the NNR-MORVEL56 model, higher residuals were found at continental coastal stations (Africa) than at oceanic ones (Canaries and Madeira). From the computed strain rate map, the possible existence of a shear zone connecting the Gloria and Transmoroccan fault systems, already mentioned by other authors, was depicted. Cluster statistical analysis of the horizontal residual velocities helped to identify tectonic boundaries in Macaronesia and four groups of analogous intraplate residual velocities within this region. Three of four groups were identified in the Azores, highlighting the African-Nubian-Eurasian diffuse plate boundary in this region. Furthermore, in the Canary Islands, two distinct kinematic behaviours were detected, possibly due to the activity along a previously detected tectonic fault between Tenerife and Gran Canaria, where some stations have similar intraplate residuals to those at Madeira and Cape Verde stations, while others have similar intraplate residuals to those of continental stations. Finally, all stations on oceanic crust, except Cape Verde, present recent ground subsidence which may be attributed to isostatic adjustment.



中文翻译:

GNSS地面位移分析的最新Macaronesian运动学

Macaronesia是一个复杂的海洋区域,横跨东北大西洋的三个构造板块。它由四个群岛组成,分布广泛,并被伊比利亚半岛东部和非洲西北海岸所限制。这项研究旨在阐明位于四个群岛以及伊比利亚和非洲海岸线上的19个GNSS站的最新的马卡诺式运动学。该分析基于近15年的通用数据采集,旨在检测板内构造的新影响或与计算得出的地面位移一致的类似局部/区域事件。相对于NNR-MORVEL56模型所预期的速度,评估GNSS站的残留速度时,发现大陆沿海站(非洲)的残留速度要比海洋站(金丝雀和马德拉群岛)高。根据计算出的应变率图,描绘了其他作者已经提到的连接Gloria和Transmoroccan断层系统的剪切带的可能存在。水平残余速度的聚类统计分析有助于确定马卡罗尼西亚的构造边界以及该区域内四组相似的板内残余速度。在亚速尔群岛中确定了四个组中的三个,突出了该区域的非洲-努比亚-欧亚扩散板边界。此外,在加那利群岛,发现了两种截然不同的运动学行为,这可能是由于沿特内里费岛和大加那利岛之间先前发现的构造断层活动所致,其中一些台站的板内残留与马德拉和佛得角台站的相似。与大陆站相似的板内残差。最后,

更新日期:2021-01-08
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