| 利用区域地震体波走时评价华北地区三维地壳速度结构模型 |
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| 引用本文： | 王耀,姚华建,房立华,吴建平.利用区域地震体波走时评价华北地区三维地壳速度结构模型[J].地震学报,2019,41(2):139-154. |
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| 作者姓名： | 王耀 姚华建 房立华 吴建平 |
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| 作者单位： | 中国合肥 230026 蒙城地球物理国家野外科学观测研究站;中国北京 100081 中国地震局地球物理研究所 |
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| 基金项目： | 国家自然科学基金面上项目（41574034）资助 |
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| 摘 要： | 本研究利用国家地震台网131个地震台站2009—2016年记录的1 749次近震的初至P波和S波走时数据，与采用快速行进方法正演计算得到的华北地区4个三维地壳速度模型对应的走时数据进行对比，通过统计分析的方法，评价这4个速度模型与真实地下结构的近似程度。结果表明:4个速度模型在大范围内存在较高的一致性，在整个研究区内（111°E—119.5°E，37°N—42°N），Shen等的模型（简称“S模型”）相对优于Fang等的模型（简称“F模型”）和Duan等的模型（简称“D模型”），Laske等的Crust1.0模型（简称“C模型”）相对较差。我们认为该结果与上述几个模型所使用的数据及其分辨率有关。对于研究区域内的构造单元，D模型在燕山褶皱带西南部、太行山山前构造带西北部和沧县隆起区表现较好，F模型在太行山隆起区中部、沧县隆起北部、黄骅凹陷区和燕山褶皱带表现较好，S模型在西部地块、山西凹陷区、太行山山前构造带和冀中凹陷区表现较好，C模型无明显连片表现较好区域。
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| 关 键 词： | 华北地区 地震走时 三维地壳速度结构 模型评价 |
| 收稿时间： | 2018-04-24 |
Evaluation of 3D crustal velocity models in North China using regional earthquake travel time data |
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| Institution: | 1.School of Earth and Space Science，University of Science and Technology of China，Hefei 230026，China2.National Geophysical Observatory at Mengcheng，Hefei 230026，China3.Institute of Geophysics，China Earthquake Administration，Beijing 100081，China |
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| Abstract: | Due to the differences in research methods and data, there may exist multiple velocity models in the same area, but the reliability of these models usually lacks systematic and objective assessment. In this study we compare the observed first arrival time data of P-wave and S-wave of 1 749 earthquakes from 2009 to 2016, which were recorded by 131 seismograph stations of the National Seismological Network in North China, with the predicted travel time data from four 3D crustal velocity models in North China using the fast marching method. Then, using statistical analysis we evaluate the relative merits of these four models with respect to the real underground structures. The results reveal that the large-scale pattern generally shows consistency for these four models. Within the entire studied area, the model proposed by Shen et al （referred to as " S model”） is relatively better than the model proposed by Fang et al （referred to as " F model”） and Duan et al （referred to as " D model”）. The Crust1.0 model （referred to as " C model”） is relatively worse. We think that the reasons for this result are related to the differences in data used in model construction and the associated resolution. For different tectonic units in the studied area, the D model performs better in the southwestern part of the Yanshan folded belt, northwestern part of the Taihang mountain foreland tectonic belt, and the Cangxian uplift area. The F model performs better in the central part of Taihang mountain uplift, northern part of the Cangxian uplifted area, the Huanghua depression, and the Yanshan fold belt. The S model appears better in the western block, the Shanxi depression area, the Taihang mountain foreland tectonic belt, and the Jizhong depression area. There is no obvious large continuous area where the C model performs better. Our study has certain positive significance for further accuracy improvement of the regional crustal velocity models and the earthquake location study based on 3D models. |
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