Structural style of Quaternary extension in the Crati Valley (Calabrian Arc): Evidence in support of an east-dipping detachment fault
Structural style of Quaternary extension in the Crati Valley (Calabrian Arc): Evidence in support of an east-dipping detachment fault
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DOI：
10.3301/ijg.2017.11
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发表时间：
2017-10-01
影响因子：
1.8
通讯作者：
Lavecchia, Giusy
中科院分区：
文献类型：
--
作者：
Brozzetti, Francesco;Cirillo, Daniele;Lavecchia, Giusy
新的地质现场数据，与商业地震测线相结合，使我们能够限制断层系统的几何形状和时空演化，该断层系统控制了北方卡拉布里亚弧轴部的NS-走向的Alzhei地堑的构造-沉积演化。我们强调，该盆地受60公里长的东倾主断层控制，在地震剖面上，CGDF表现为沿Catena Costiera Calabra东坡沿着到达地表的东倾低角度反射。其地表表现为中等倾角（30 ° ~ 45 °）的左阶式钳形断层，更向东，有一些东西向的高角度正断层从CGDF向上分支。重建的时间表明，最西端的断裂自早更新世以来一直处于活动状态，并表现出向东逐渐恢复的趋势。通过对一个横跨整个Tagani地堑的东西向地震剖面的深度转换，突出了CGDF具有一个阶梯几何形状，平均角度为30度，到达盆地东侧以下7-8 km的深度。利用Move软件对剖面进行复原，重建了相关断层系统的演化阶段（米德兰河谷勘探），以验证我们的地下解释的运动学一致性和估计联合延伸的量。最后，对CGDF的现今活动和可能的孕震作用进行了初步讨论。通过将伸展断层系统的几何形状与现有的历史和地震仪器数据集进行比较。
New geological field data, integrated with commercial seismic lines, allowed us to constrain the geometry and time-space evolution of the fault system that ruled the tectono-sedimentary evolution of the NS-striking Crati graben, in the axial portion of the northern Calabrian Arc.We highlight that this basin is controlled by a 60-km long east-dipping master fault, referred to as the Crati Graben Detachment Fault (CGDF).On the seismic sections, the CGDF appears as an east-dipping low-angle reflection reaching the surface along the eastern slope of the Catena Costiera Calabra. Its surface expression corresponds to an alignment of moderately-inclined (30 degrees to 45 degrees) left-stepping en-chelon faults.More to the East, a number of E- and W-dipping high-angle normal faults branch upward from the CGDF. Their reconstructed timing suggest that the westernmost faults are active since the Early Pleistocene and show a progressive eastward rejuvenation trend.The conversion to depth of a W-E oriented seismic section, crossing the entire Crati graben, highlights that the CGDF has a staircase geometry, with an average angle of 30 degrees, and reaches a depth of 7-8 km below the east side of the basin. The evolutionary stages of the related fault system were reconstructed by restoring the section through the Move suite software (Midland Valley Exploration), in order to verify the kinematic consistency of our subsurface interpretation and estimate the amount of associate extension.Finally, the present activity and the possible seismogenic role of the CGDF is preliminarily discussed, by comparing the geometry of the extensional fault system with the available historical and seismological instrumental datasets.