| 福建省重力台网对米娜台风激发的微震信号源定位 |
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| 引用本文： | 韦进,胡敏章,韩宇飞,鲁小飞,江颖.福建省重力台网对米娜台风激发的微震信号源定位[J].武汉大学学报(信息科学版),2022,47(6):955-963. |
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| 作者姓名： | 韦进 胡敏章 韩宇飞 鲁小飞 江颖 |
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| 作者单位： | 1.中国地震局地震研究所，湖北 武汉, 430071 |
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| 基金项目： | 国家自然科学基金41204058武汉引力与固体潮国家野外科学观测研究站开放研究基金WHYWZ202106 |
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| 摘 要： | 利用重力台网进行台风激发信号的源区定位研究不仅有助于提高台风监测能力，而且可从台风激发信号中区分出震前与震源有关的信号，促进地震预测研究。以2019年第18号台风米娜(MITAG)为研究对象，基于福建省重力台网观测的1 Hz采样的固体潮观测数据，利用噪声互相关函数的信噪比(signal-to-noise ratio，SNR)和归一化噪声能量流方法分析数据质量和微震源区方位，使用SNR≥25的Rayleigh波互相关信号走时作为定位数据，进行台风4个时段的定位研究。结果表明，在MITAG台风靠近中国大陆的过程中，定位区域能够覆盖台风中心所在位置；地震背景噪声能量辐射模型的微震垂直位移极值区域也和台风靠近中国大陆过程时段一致；通过人工剔除高速波群的互相关信号后，定位区域也能覆盖到转向远离大陆过程时段的台风轨迹。福建省重力台网对台风的追踪提供一类新的数据和方法。
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| 关 键 词： | 重力台网 微震信号 互相关函数 定位 |
| 收稿时间： | 2022-05-20 |
MITAG Typhoon Location Based on Microseismic Signal of Gravity Network in Fujian Province |
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| Affiliation: | 1.Institute of Seismology, China Earthquake Administration, Wuhan 430071, China2.National Observation and Research Station of Gravitation and Earth Tide, Wuhan 430071, China3.Hubei Earthquake Administration, Wuhan 430071, China4.China Earthquake Networks Center, Beijing 100045, China |
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| Abstract: | Objectives With the development of gravity observation technology, the typhoon tracking research by gravity network composed of gPhone with 1 Hz sampling rate can not only improve the ability of typhoon monitoring, but also distinguish the pre-earthquake anomalous signals related to earthquake hypocenters from typhoon excitation signals, thereby improving the ability of earthquake prediction. Methods Firstly, the original gravity earth tide data are pre-processed and cross-correlated as the ambient noise cross-correlation function(NCF) matrix from the gravity network in Fujian Province and its adjacent areas. Secondly, by selecting the NCF with signal-to-noise ratio (SNR)≥25 as NCF matrix and calculating the optimal azimuth of the signal source by the normalized background energy flux (NBEF) method, the NCF matrix is sorted by the distance of gravity station pairs and the travel time of the Rayleigh wave cross-correlated signal is confirmed. Assuming that the speed of microseisms is 2.9 km/s in the ocean, and 11 km/s in the land, the normalized value in the location area is calculated by the difference of travel time from a signal source to the gravity station pairs in research region. The minimal normalized value in locating area is the typhoon center or the excited signal source. Meanwhile, the microseisms vertical displacement simulated with the Ardhuin seismic spectra model (ASSM) and the optimal path of MITAG typhoon(2019) has been used to check the reliability of the locating results. Finally, the 7 optimal azimuth estimated strategies have been used for comparison of typhoon orientation, and the influence of the high-speed cross-correlated signal has been discussed to verify the reliability of the location method. Results When the MITAG typhoon is approaching the gravity network, the locating area can cover the location of the typhoon center. The extreme value region of the microseism vertical displacement simulated by the ASSM model is also consistent with the typhoon path during the period of approaching the gravity network. After eliminating the NCF with high-speed cross-correlated signals, the location area can also cover the typhoon trajectory during the period of turning away from the gravity network. Conclusions By specifying SNR and distance of gravity station pairs and excluding NCFs with high-speed cross-correlated signal, the Raleigh wave cross-correlated signal travel time locating method can be used to trace the typhoon based on Fujian Province gravity network. The study can provide new data and methods for tracking typhoons by gravity network. |
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