软沉积物变形中负载、球—枕构造的古地震研究综述

发布时间：2018-10-20 11:36

【摘要】：在构造活动地区,软沉积物变形是研究古地震的一种关键证据。近年来,湖相沉积中的软沉积物变形受到越来越多的关注,但多数研究局限于软沉积物变形的形态分类。相比之下,对软沉积物变形的成因分析、触发机制和变形过程缺少系统分析,以至于软沉积物变形能否反映地震事件,以及软沉积物变形类型、强弱与地震震级和震中位置是否存在明确关联还存在较大争议。鉴于此,本文选择软沉积物变形中典型的变形构造—负载、球—枕构造,从其具体特征、成因、触发机制、变形过程、变形强弱与震级及震中距关系等方面展开讨论。统计结果显示,当沉积记录中的负载、球—枕构造为地震成因时,其代表的震级可能为6.0~7.0级,震中距约为20~70 km。就相同变形强度的负载、球—枕构造来说,湖相沉积记录的震级最强,其次为河湖相沉积和海相沉积。负载、球—枕构造变形层的宽度和厚度以及球状半径大小与地震震级具有正相关关系,而岩性与地震震级大小没有直接的对应关系。利用软沉积物变形所对应的地震震级估算距震中距离,或者采用软沉积物变形距断层距离估算地震震级的方法都是可行的。这样看来,软沉积物变形不仅能够记录地震事件,而且能够根据其变形类型、尺度大小和强度变化等,较好地确定地震震级及震中位置,为古地震研究提供了一个相对独立的研究方向。
[Abstract]:In tectonic active areas, the deformation of soft sediments is a key evidence for the study of paleoearthquakes. In recent years, more and more attention has been paid to the deformation of soft sediments in lacustrine sediments, but most of the studies are limited to the morphological classification of soft sediments. In contrast, there is a lack of systematic analysis on the causes, trigger mechanism and deformation process of soft sediment deformation, so that whether the deformation of soft sediment can reflect earthquake events, as well as the types of deformation of soft sediment, Whether there is a clear correlation between magnitude and epicenter location is still controversial. In view of this, the typical deformation tectonics-load and ball-pillow structures in soft sediment deformation are selected and discussed from the following aspects: specific characteristics, origin, trigger mechanism, deformation process, the relationship between deformation intensity and magnitude and epicentral distance. The statistical results show that when the load in the sedimentary record and the spheric-pillow structure are the origin of the earthquake, the magnitude of the earthquake may be 6.0 or 7.0, and the epicentral distance is about 20 ~ 70 km.. For the same deformation intensity, the seismogram of lacustrine facies is the strongest, followed by fluvial facies and marine facies. The width and thickness of the deformation layer and the radius of the spherical structure are positively correlated with the magnitude of the earthquake, but there is no direct correlation between the lithology and the magnitude of the earthquake. It is feasible to estimate the distance from the epicenter to the earthquake magnitude corresponding to the deformation of the soft sediment or to estimate the magnitude of the earthquake by using the distance from the deformation of the soft sediment to the fault. In this way, the deformation of soft sediment can not only record earthquake events, but also determine the magnitude and epicenter location of the earthquake according to its deformation type, scale size and intensity change, etc. It provides a relatively independent research direction for paleoseismic research.
【作者单位】：中国地震局地质研究所地震动力学国家重点实验室;北京工业大学建筑工程学院;中国地质大学(北京)地球科学与资源学院;
【基金】：中国地震局地质研究所基本科研业务专项(编号:IGCEA1508) 地震动力学国家重点实验室自主课题(编号:LED2013A03) 国家自然科学基金资助项目(编号:41572346)的成果~~
【分类号】：P315

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