方孙珂2,
倪四道3
1. 浙江省海洋观测-成像试验区重点实验室, 浙江大学, 浙江舟山 316021
2. 浙江大学海洋学院, 浙江舟山 316021
3. 大地测量与地球动力学国家重点实验室, 中科院精密测量科学与技术创新研究院, 武汉 430071
基金项目: 国家重点研发计划项目（2018YFC1503204），国家自然科学基金（41874046），浙江省重点研发计划项目（2021C03181）共同资助
详细信息
作者简介: 林建民, 男, 1981年生, 博士, 副教授, 主要从事海洋地球物理和声学海洋学研究.E-mail: jmlin@zju.edu.cn
中图分类号: P738 收稿日期:2021-01-20
修回日期:2021-07-02
上线日期:2021-12-10
Investigation of typhoon Kalmaegi-induced microseism source regions using combined seismic arrays
LIN JianMin1,2,,FANG SunKe2,
NI SiDao3
1. Key Laboratory of Ocean Observation-Imaging Testbed of Zhejiang Province, Zhejiang University, Zhoushan Zhejiang 316021, China
2. Ocean College, Zhejiang University, Zhoushan Zhejiang 316021, China
3. State Key Laboratory of Geodesy and Earth's Dynamics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
MSC: P738
--> Received Date: 20 January 2021
Revised Date: 02 July 2021
Available Online: 10 December 2021
摘要
摘要:利用台风所激发的P波地脉动信号，地震学家近年来开始尝试通过地震学方法定位、监测台风.由于单台阵定位精度的局限性（主要取决于台站数目、孔径和结构等），本文提出了将台阵至源区的距离作为归一化权重因子、结合反卷积技术的双台阵联合定位方法，并利用中国喜马拉雅二期台阵（ChinArray Ⅱ）和日本高灵敏度地震台网（Hi-net）的连续波形数据，对2014年西北太平洋强台风"海鸥"所激发的P波地脉动源区进行了定位测试.联合定位结果与理论模拟源区具有较好一致性：台风"海鸥"位于菲律宾海时，其激发海浪与台风"风神"遗留涌浪相互作用而激发的P波地脉动源区偏离"海鸥"移动轨迹；而当"海鸥"进入南海后，其激发的P波源区则紧随台风中心.与单台阵定位结果的对比分析表明，本文所提出的方法能够有效降低以下方面影响：（1）单台阵响应函数强旁瓣导致定位结果出现"伪影"、不聚焦；（2）台阵至源区距离小于~26°时，P波沿复杂浅地层传播时实际走时与基于理想地球模型的理论预测走时存在较大偏差导致近场定位误差增大；以及（3）上地幔三重震相的干扰等.因此，该方法有效提升了定位结果的聚焦性与稳定性，实现对"海鸥"激发P波地脉动源区的全程、稳定定位追踪，为发展基于地震学的台风监测新方法提供支持.
关键词: 台风/
地脉动/
地震台阵/
定位
Abstract:Using typhoon-induced P-wave microseisms as a proxy,seismologists have devoted themselves to monitor typhoons through seismological methods in recent years. Considering the shortness of localization accuracy and resolution by a single seismic array (mainly depending on the number of stations,array aperture,configuration,etc.),we present an effective double-seismic-array-combination (DSAC)-based localization method,that employs deconvolution technique and introduces a weight factor in terms of distance from array to target source region. We locate the P-wave microseism source regions generated by the super typhoon Kalmaegi (2014) in the Western North Pacific using the continuous seismic waveform data from the ChinArray Ⅱ and Hi-net. The DSAC-based localization results are quite consistent with the theoretical source regions: When Kalmaegi was over the Philippine Sea,the localized source area of P-wave microseisms excited by the interaction between the Kalmaegi-generated waves and the swells induced by Typhoon Fengshen deviated from the moving track of Kalmaegi; but the localized source area turned to follow the typhoon center after Kalmaegi entered the South China Sea. Comparing with single-array-based localization results,the DSAC-based localization method could mitigate the following effects: (1) Artifacts in the localization results arising from high side lobe levels of the array response function (ARF); (2) Amplification of the localization error due to the deviation between the actual travel time of P wave microseisms propagating in the complex shallow subsurface structure and the theoretical one calculated based on ideal Earth models,especially when the offset from the array to source region is smaller than ~26°; and (3) Interference from upper-mantle triplications. Consequently,we improve the localization results significantly and track the Kalmaegi-induced P-wave microseism source regions successfully during the entire typhoon lifespan by applying this method,offering a small leap forward in seismic monitoring of ocean storms.
Key words:Typhoon/
Microseism/
Seismic array/
Localization
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