Deep structure and tectonics of the northern-central Apennines as seen by regional-scale tomography and 3-D located earthquakes
Deep structure and tectonics of the northern-central Apennines as seen by regional-scale tomography and 3-D located earthquakes
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DOI：
10.1002/jgrb.50371
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发表时间：
2013-10-01
影响因子：
3.9
通讯作者：
Chiarabba, C.
中科院分区：
文献类型：
--
作者：
Carannante, S.;Monachesi, G.;Chiarabba, C.
在这项研究中，我们提出了新的高分辨率、区域尺度的亚平宁中北部地区的Vp和Vp/Vs模式，以及一大批地方地震的准确三维位置。主要速度异常与浅层地表地质相一致，为伸展带下方较深的基底内储存流体提供了证据。Adria和Tyrrhenian地幔由30公里以下的正速度异常所定义，而介于两者之间的低Vp、高Vp/Vs区域则指示存在水化楔体。这些结果对亚平宁山脉的活动过程产生了新的限制，更普遍地设想了碰撞后带的演化。速度异常和地震与阿德里亚大陆岩石圈拆沉和下沉的复杂系统相一致，地壳剥离是由中深部地震活动确定的。地震活动和沿带构造格局的变化表明，这一构造过程是历时的，岩石圈下沉释放的流体储存在地壳内，制约了地震活动的发生和伸展的开始。
In this study we present new high-resolution, regional-scale, Vp and Vp/Vs models of the northern-central Apennines along with accurate 3-D locations of a large set of local earthquakes. The main velocity anomalies are consistent with the surface geology in the shallow layers and present evidence for fluids stored within the basement at greater depths beneath the extensional belt. The Adria and Tyrrhenian mantle are defined by positive velocity anomalies below 30 km depth, while a low-Vp, high-Vp/Vs region in between indicates the existence of a hydrated wedge. The results yield new constraints on active processes in the Apennines and more generally envisage the evolution of a postcollisional belt. Velocity anomalies and earthquakes are consistent with a complex system of delamination and sinking of the Adria continental lithosphere, with the peeling of the crust identified by intermediate-depth seismicity. Change of seismicity and structural patterns along the belt indicates that this tectonic process is diachronous and that fluids, released by sunken lithosphere, are stored within the crust, conditioning the occurrence of seismicity and the onset of extension.