Honglei Li, Shi Chen, Bei Zhang, Yongbo Li, J. Zhuang
Recently, the eastern margin of the Tibetan plateau has experienced three moderate earthquakes. Deep crustal structure is a critical factor for understanding the seismotectonic environment and deformations in this region. While several multidisciplinary geophysical approaches have been employed to develop crustal structure models for this area, substantial inconsistencies still persist in the results due to the intricate structural properties of crust. In this study, we introduce a novel approach to construct a three-dimensional crustal model with assimilated density structure (MADS) at a resolution of 0.2° ×0.2°×5 km. This model is built by integrating data from various source, including multi-source gravity anomalies and diverse available crustal structure reference models. We employ a model-assimilated gravity inversion process with Bayesian parameter optimization. Firstly, we combine the terrestrial gravity profiles dataset with published global gravity field models to create a dataset rich in reliable high-frequency anomaly information. Secondly, we incorporate three reference models derived from different seismological methods as prior constraints for our model. These models encompass seismic tomography, surface wave dispersion and receiver function data. We optimize the hyper-parameters of these constraints using the Bayesian criterion. The results demonstrate that the MADS not only captures significant changes in the crustal density but also discerns subtle variations in the upper and middle crust, thereby providing detailed insights into the morphologies of major faults. For instance, the central section of the Longmenshan fault is revealed as a high-angle deep thrust feature, while the frontal section of the Longmenshan fault appears as a low-angle mid-deep thrust feature, and the Xianshuihe fault exhibits a vertical deep subduction feature. Additionally, our findings indicate a correlation between the locations of moderate-to-large earthquakes in this region and the high density-gradient zones or asperities with high density within MADS. We believe that the insights into density characteristics offered by the new MADS model can shed light on the study of asperities associated with recent moderate earthquakes and enhance our understanding of deformation in this region.
最近，青藏高原东缘发生了三次中强地震。深部地壳结构是了解该地区地震构造环境和变形的关键因素。虽然已经采用了多种多学科地球物理方法来建立该地区的地壳结构模型，但由于地壳结构特性错综复杂，结果仍然存在很大的不一致性。在这项研究中，我们引入了一种新方法，以 0.2°×0.2°×5 km 的分辨率构建具有同化密度结构（MADS）的三维地壳模型。该模型是通过整合各种来源的数据建立的，包括多源重力异常和各种可用的地壳结构参考模型。我们采用了贝叶斯参数优化的模型同化重力反演过程。首先，我们将陆地重力剖面数据集与已发布的全球重力场模型相结合，创建了一个富含可靠高频异常信息的数据集。其次，我们将从不同地震学方法中得出的三个参考模型作为模型的先验约束条件。这些模型包括地震层析成像、表面波频散和接收函数数据。我们使用贝叶斯标准优化了这些约束的超参数。结果表明，MADS 不仅能捕捉到地壳密度的显著变化，还能辨别中上地壳的细微变化，从而提供有关主要断层形态的详细见解。例如，龙门山断层的中段显示为高角度深冲地貌，龙门山断层的前段显示为低角度中深冲地貌，而咸水河断层则显示为垂直深俯冲地貌。此外，我们的研究结果表明，该地区中大型地震的发生地点与 MADS 内的高密度梯度带或高密度尖顶之间存在相关性。我们相信，新的 MADS 模型提供的对密度特征的见解可以为研究与近期中度地震相关的非主流提供启示，并增强我们对该地区变形的理解。
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{"title":"Correction to: De-noising receiver function data using the Seislet Transform","authors":"","doi":"10.1093/gji/ggad444","DOIUrl":"https://doi.org/10.1093/gji/ggad444","url":null,"abstract":"","PeriodicalId":502458,"journal":{"name":"Geophysical Journal International","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139289883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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