• 中文核心期刊要目总览
  • 中国科技核心期刊
  • 中国科学引文数据库(CSCD)
  • 中国科技论文与引文数据库(CSTPCD)
  • 中国学术期刊文摘数据库(CSAD)
  • 中国学术期刊(网络版)(CNKI)
  • 中文科技期刊数据库
  • 万方数据知识服务平台
  • 中国超星期刊域出版平台
  • 国家科技学术期刊开放平台
  • 荷兰文摘与引文数据库(SCOPUS)
  • 日本科学技术振兴机构数据库(JST)

基于背景噪声层析成像的北天山乌鲁木齐前陆冲断构造带高分辨率三维浅部地壳结构研究

High-resolution 3D shallow crustal structure of Urumqi foreland thrust tectonic belt, northern Tianshan, based on ambient noise tomography

  • 摘要: 乌鲁木齐前陆冲断构造带具有复杂的地质构造和强烈的地震活动性。开展该区域浅部地壳结构成像研究,对于理解其构造活动机制和孕震环境具有重要意义。我们基于布设于该区域的80多个密集地震台阵数据开展了背景噪声层析成像研究,获得了0-8公里深度的浅部地壳高分辨率S波速度模型。我们的模型相对于已有模型精度更高,更好地揭示了该区域的构造特征。沉积层分布特征表现为在东南部普遍较薄,而在西北部较厚,最大厚度超过8公里。西山、碗窑沟和雅玛里克断裂附近的速度结构变化表明,断裂的形成与其两侧的物性差异有关,且这些断裂都表现出低速侧向高速侧的逆冲作用。在研究区内,在3公里深度以内地震较少且大多集中在南部的高速区。而在3公里深度以下观测到更多的地震,主要分布在断裂附近或南部相对高速区域。这表明南部的高速结构更容易积累应力,从而导致地震发生。在6-8公里深度,博格达山脉西北部密集分布的地震与本研究观测到的一条西北走向的低速区具有很好的对应性,推测该构造薄弱带可能对该区域的地震活动性具有控制作用。

     

    Abstract: The Urumqi foreland thrust tectonic belt exhibits complex geological structures and strong seismicity. Imaging its shallow crustal structure is of great significance for understanding its tectonic mechanism and seismogenic environment. We obtained a high-resolution S-wave velocity model of the shallow crust at depths of 0–8 km using ambient noise tomography applied to data from a dense seismic array. Sediments are generally thinner in the southeast and thicker in the northwest, with a maximum thickness of more than 8 km. Variations in the velocity structure near the Xishan, Wanyaogou, and Yamalike faults indicate that their formation was related to differences in the physical properties on either side of the fault. In addition, the faults exhibit thrusting of the low-velocity sides towards the high-velocity sides. In the study area, earthquakes rarely occur at depths of less than 3 km and are mostly concentrated in the high-velocity zone in the southern part. Below 3 km depth, more earthquakes were observed, mainly distributed near faults or in relatively high-velocity areas in the southern part. This suggests that high-velocity structures are more prone to stress accumulation, resulting in earthquakes. At 6–8 km depth, the densely distributed earthquakes in the northwestern part of the Bogda mountains are well-aligned with the northwest-oriented low-velocity zone observed in this study, suggesting that this weak zone likely controls seismicity in this area.

     

/

返回文章
返回