CAJ | 학술논문

FAST(first arrival seismic tomography)软件是获取复杂地区三维深部结构的最常用工具之一,而反演参数选取是快速有效地获得真实合理的地震结构的关键环节。以南海中央次海盆三维地震探测数据为基础,采用先固定其中一个参数、选取另外一个参数、再综合选取的控制变量法,详细地介绍了FA S T反演参数组合的选取过程。选取结果表明,反演参数组合(阻尼因子λ=2,平滑度权重因子sz=1,反演次数I=4)为南海中央次海盆三维地震结构的最佳反演参数,由此获得的最佳初步速度模型表明中央次海盆具有典型慢速扩张的洋壳结构。此项反演参数选取工作不仅为珍贝-黄岩海山链精细三维地震结构的正式模拟奠定了基础,同时为FA S T软件在其他地区的应用提供了丰富的经验与借鉴。
FAST(first arrival seismic tomography)연건시획취복잡지구삼유심부결구적최상용공구지일,이반연삼수선취시쾌속유효지획득진실합리적지진결구적관건배절。이남해중앙차해분삼유지진탐측수거위기출,채용선고정기중일개삼수、선취령외일개삼수、재종합선취적공제변량법,상세지개소료FA S T반연삼수조합적선취과정。선취결과표명,반연삼수조합(조니인자λ=2,평활도권중인자sz=1,반연차수I=4)위남해중앙차해분삼유지진결구적최가반연삼수,유차획득적최가초보속도모형표명중앙차해분구유전형만속확장적양각결구。차항반연삼수선취공작불부위진패-황암해산련정세삼유지진결구적정식모의전정료기출,동시위FA S T연건재기타지구적응용제공료봉부적경험여차감。
First arrival seismic tomography (FAST) is one of the most widely used seismic tomography tools to achieve complicated three-dimensional (3D) deep crustal structure. The selection of optimal inversion parameters for FAST is a key to obtain a reasonable velocity model effectively. Based on the 3D seismic survey data collected from the central sub-basin of the South China Sea (SCS), the selection process of inversion parameters was illustrated in detail in this paper, using the control variate method, namely, selecting one parameter while fixing the other parameters, and then selecting the combination of all parameters comprehensively. The result showed that the combination of parameters (damping parameterλ=2, smoothness weighting parametersz=1, inversion numberI=4) was an assembly of optimal inversion parameters for the 3D seismic structure of the central sub-basin of the SCS. The preferred preliminary velocity structure acquired by this combination indicated that the central sub-basin could be classified as a typical slow-spreading oceanic crust. The research of choosing inversion parameters not only lays a foundation for further modeling of detailed 3D seismic structure of the Zhenbei-Huangyan seamount chain but also provides reference and experience for the application of FAST software in other potential areas.