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Analysis of the Frequency Domain Water-level Deconvolution Method Based on Reservoir Airgun Source Data

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earthquake Research in China 2018年第3期32卷 355-366页

作者： You Xiuzhen Li Jun Lin Binhua Huang Yandan Wu Lihua Guo Yang fujian earthquake agency Fuzhou 350003China

Based on the 2016 airgun experimental data of the fujian Nanyi reservoir,we adopted the frequency domain water-level deconvolution method and cross-correlation time delay detection technique to study the influence of level scaling factor and the background noise level of the station on deconvolution calculation results, and analyze the effect of deconvolution on eliminating the influence of the source caused by different air-gun pressures. The results show that:( 1) When the level scaling factor is smaller,the signal to noise ratio of the waveform after the deconvolution is smaller,and when the level scaling factor is over smaller,the identification error of travel time is greater.( 2) When the SNR of the station record is higher,the recognition accuracy of travel time is higher,the influence of SNR on the reference station record is far greater than the far station,when the SNR of the far station record is more than 10,the error of travel time is within6 ms,but when the SNR of the reference station record is 30,the travel time error may reach to 20 ms.( 3) When the airgun source difference is big,the frequency domain waterlevel deconvolution method has better effect on eliminating the source influence,but the method error may be introduced when the source difference is small.

关键词： Large volume airgun Water-level deconvolution in frequency domain Cross-correlation time delay Green s function

High-precision relocation of the aftershock sequence of the January 8,2022,M_(S)6.9 Menyuan earthquake

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earthquake Science 2022年第2期35卷 138-145页

作者： Liping Fan Boren Li Shirong Liao Ce Jiang Lihua Fang Institute of Geophysics China Earthquake AdministrationBeijing 100081China Guangdong earthquake agency Guangzhou 510405China fujian earthquake agency Fuzhou 350003China Key Laboratory of earthquake Source Physics China Earthquake AdministrationBeijing 100081China

The 2022 Menyuan M_(S)6.9 earthquake,which occurred on January 8,is the most destructive earthquake to occur near the Lenglongling(LLL)fault since the 2016 Menyuan M_(S)6.4 *** relocated the mainshock and aftershocks with phase arrival time observations for three days after the mainshock from the Qinghai Seismic Network using the double-difference *** total length and width of the aftershock sequence are approximately 32 km and 5 km,respectively,and the aftershocks are mainly concentrated at a depth of 7-12 *** relocated sequence can be divided into 18 km west and 13 km east segments with a boundary approximately 5 km east of the mainshock,where aftershocks are *** east and west fault structures revealed by aftershock locations differ *** west fault strikes EW and inclines to the south at a 71°-90°angle,whereas the east fault strikes 133°and has a smaller dip *** strain accumulates at conjunctions of faults with different slip rates where it is prone to large *** on surface traces of faults,the distribution of relocated earthquake sequence and surface ruptures,the mainshock was determined to have occurred at the conjunction of the Tuolaishan(TLS)fault and LLL fault,and the west and east segments of the aftershock sequence were on the TLS fault and LLL fault,*** migrate in the early and late stages of the earthquake *** the first 1.5 h after the mainshock,aftershocks expand westward from the *** the late stage,seismicity on the northeast side of the east fault is higher than that in other *** migration rate of the west segment of the aftershock sequence is approximately 4.5 km/decade and the afterslip may exist in the source region.

关键词： Menyuan earthquake aftershock sequence double-difference relocation Lenglongling fault Tuolaishan fault

Real-time 3-D space numerical shake prediction for earthquake early warning

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earthquake Science 2017年第5期30卷 269-281页

作者： Tianyun Wang Xing Jin Yandan Huang Yongxiang Wei Institute of Engineering Mechanics China Earthquake AdministrationHarbin 150080China Key Laboratory of earthquake Engineering and Engineering Vibration China Earthquake AdministrationHarbin 150080China fujian earthquake agency Fuzhou 350003China

In earthquake early warning systems, real-time shake prediction through wave propagation simulation is a promising approach. Compared with traditional methods, it does not suffer from the inaccurate estimation of source parameters. For computation efficiency, wave direction is assumed to propagate on the 2-D surface of the earth in these methods. In fact, since the seismic wave propagates in the 3-D sphere of the earth, the 2-D space modeling of wave direction results in inaccurate wave estimation. In this paper, we propose a 3-D space numerical shake pre- diction method, which simulates the wave propagation in 3-D space using radiative transfer theory, and incorporate data assimilation technique to estimate the distribution of wave energy. 2011 Tohoku earthquake is studied as an example to show the validity of the proposed model. 2-D space model and 3-D space model are compared in this article, and the prediction results show that numerical shake prediction based on 3-D space model can estimate the real-time ground motion precisely, and overprediction is alleviated when using 3-D space model.

关键词： Real-time numerical shake prediction· 3-Dspace model · Radiative transfer theory · Data assimilation

Real-time numerical shake prediction and updating for earthquake early warning

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earthquake Science 2017年第5期30卷 251-267页

作者： Tianyun Wang Xing Jin Yongxiang Wei Yandan Huang Institute of Engineering Mechanics China Earthquake AdministrationHarbin 150080China Key Laboratory of earthquake Engineering and Engineering Vibration China Earthquake AdministrationHarbin 150080China fujian earthquake agency Fuzhou 350003China

Ground motion prediction is important for earthquake early warning systems, because the region＇s peak ground motion indicates the potential disaster. In order to predict the peak ground motion quickly and pre- cisely with limited station wave records, we propose a real- time numerical shake prediction and updating method. Our method first predicts the ground motion based on the ground motion prediction equation after P waves detection of several stations, denoted as the initial prediction. In order to correct the prediction error of the initial prediction, an updating scheme based on real-time simulation of wave propagation is designed. Data assimilation technique is incorporated to predict the distribution of seismic wave energy precisely. Radiative transfer theory and Monte Carlo simulation are used for modeling wave propagation in 2-D space, and the peak ground motion is calculated as quickly as possible. Our method has potential to predict shakemap, making the potential disaster be predicted before the real disaster happens. 2008 Ms8.0 Wenchuan earthquake is studied as an example to show the validity of the proposed method.

关键词： Real-time numerical shake prediction· 2-Dspace model · Radiative transfer theory · Dataassimilation · Shakemap prediction

Surface Wave Group Velocity Tomography Imaging from Ambient Noise for fujian Province and Its Adjacent Areas

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earthquake Research in China 2019年第1期33卷 52-61页

作者： ZHANG Lina LUO Yan CHEN Zhiyong XIE Zhizhao ZHOU Lanjie ZENG Xiangfang Xiamen Seismic Survey Research Center Fujian Earthquake Agency Institute of earthquake Forecasting CEA fujian earthquake agency State Key Laboratory of Geodesy and Earths Dynamics Institute of Geodesy and Geophysics Chinese Academy of Sciences

Two-month continuous waveforms of 108 broadband seismic stations in fujian Province and its adjacent areas are used to compute noise cross-correlation function(NCF). The signal quality of NCF is improved via the application of time-frequency phase weighted stacking. The Rayleigh and Love waves group velocities between 1 s-20 s are measured on the symmetrical component of the NCF with the multiple filter method. More than 5,000 Rayleigh wave dispersion curves and about 4,000 Love wave dispersion curves are obtained and used to invert for group velocity maps. This data set provides about 50 km resolution that is demonstrated with checkerboard tests. Considering the off great circle effect in inhomogeneous medium, the ray path is traced based on the travel time field computed with a finite difference method. The inverted group velocity maps show good correlation with the geological features in the upper and middle crust. The Fuzhou basin and Zhangzhou basin showed low velocity on the short period group velocity maps. On the long period group velocity maps, the low velocity anomaly in the high heat flow region near Zhangzhou and clear velocity contrast across the Zhenghe-Dapu faults, which suggests that the Zhenghe-Dapu fault might be a deep fault.

关键词： fujian Ambient noise Surface wave group velocity Tomography imaging

Real-time prediction of earthquake potential damage:A case study for the January 8,2022 M_(S) 6.9 Menyuan earthquake in Qinghai,China

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earthquake Research Advances 2023年第1期3卷 52-60页

作者： Jindong Song Jingbao Zhu Yongxiang Wei Shuilong Li Shanyou Li Key Laboratory of earthquake Engineering and Engineering Vibration Institute of Engineering MechanicsChina Earthquake AdministrationHarbin 150080China Key Laboratory of earthquake Disaster Mitigation Ministry of Emergency ManagementHarbin 150080China fujian earthquake agency Fuzhou 350003China

It is critical to determine whether a site has potential damage in real-time after an earthquake occurs,which is a challenge in earthquake disaster ***,we propose a real-time earthquake Potential Damage predictor(EPDor)based on predicting peak ground velocities(PGVs)of *** EPDor is composed of three parts:(1)predicting the magnitude of an earthquake and PGVs of triggered stations based on the machine learning prediction models;(2)predicting the PGVs at distant sites based on the empirical ground motion prediction equation;(3)generating the PGV map through predicting the PGV of each grid point based on an interpolation process of weighted average based on the predicted values in(1)and(2).We apply the EPDor to the 2022 M_(S) 6.9 Menyuan earthquake in Qinghai Province,China to predict its potential *** the initial few seconds after the first station is triggered,the EPDor can determine directly whether there is potential damage for some sites to a certain ***,we infer that the EPDor has potential application for future ***,it also has potential in Chinese earthquake early warning system.

关键词： earthquake early warning Potential damage Machine learning 2022 M_(S)6.9 Menyuan earthquake Magnitude estimation On-site peak ground velocity prediction

Cooling and exhumation of the Late Cretaceous Laojunshan granites in southeast Yunnan Province， China: constraints from fission-track thermochronology and tectonic implications

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Journal of Earth Science 2022年

作者： Fang Li Hao Bai Ye Fang Da Zhang Ganguo Wu Wei Xue Chaoyang Que Xinming Zhang Xiaolong He Bojie Hu China University of Geosciences (Beijing) fujian earthquake agency Zijin Mining Group Co.， Ltd.

The Song Chay Dome in southeastern Yunnan Province， China， is intruded by the Late Cretaceous Laojunshan granites. New apatite and zircon fission-track data for the Laojunshan granites allow us to reconstruct the exhumation history of the Song Chay Dome. The fission-track dating indicates that the Laojunshan granites experienced four main stages of rapid cooling and exhumation at 75–63， 53–43， 31–20， and 12–4 Ma. The first stage was related to the thermal equilibration with surrounding rocks after magma emplacement. The rapid cooling and exhumation at 53–43 Ma were caused by normal faulting in the late Mesozoic–early Cenozoic extensional setting of southwestern South China， which resulted in the Laojunshan granites and Song Chay Dome being exhumed in the footwall of faults. The third stage (31–20 Ma) was the result of southeastward extrusion of the Tibetan Plateau and sinistral strike-slip movement on the NW–SE-trending Nanwenhe and Maguan–Dulong faults. The 31 Ma representing the beginning of the interaction between the Tethyan Himalayan tectonic domain and the South China Block. The final stage was mainly due to activity on the Nanwenhe Fault to the north of the Laojunshan granites， caused by lateral extrusion of the southeastern Tibetan Plateau since ca. 15Ma. These cooling and exhumation events since the Late Cretaceous indicate that the Song Chay Dome and southwestern South China Block have been affected by the Himalayan Orogeny since the Oligocene.

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Resonance Analysis in a High-Rise Building: Combined Translational and Rotational Measurements

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Journal of Earth Science 2024年第3期35卷 1069-1074页

作者： Linpeng Qin Yun Wang Chang Chen Yongxiang Wei Chunqi Liao Yi Zhang Chao Wang Wentao Wan Quanyang Shao School of Geophysics and Information Technology China University of GeosciencesBeijing 100083China fujian earthquake agency Fuzhou 350003China Institute of Geochemistry Chinese Academy of SciencesGuiyang 550081China

0 INTRODUCTION Resonance frequency is an important indicator for structure health monitoring,which can be exacerbated by various natural forces,such as rainfall,earthquakes,and hurricanes(Wu et al.,2021;Shan et al.,2020;Gentile et al.,2016;Moser and Moaveni,2011).Clinton et al.(2006)found that changes in environmental factors could significantly affect the resonance frequency of the Millikan Library;and that compared with temperature,humidity and strong wind have greater impacts on resonance ***,some studies have confirmed the effects of environmental factors through mathematical statistical analyses,including Xia et al.(2006),Yuen and Kuok(2010),and Guéguen et al.(2017).Other studies(e.g.,Astorga et al.,2018)revealed a building’s self-healing ability,where the building’s resonance frequency drifts due to earthquake events,environmental factors,or random forced vibrations could gradually return to its original level,but the recovery time of frequency drift could be considerably different with respect to different environmental factors.

关键词： humidity rainfall earthquake

Methods for estimating rotational components of seismic ground motion and their numerical comparisons

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earthquake Science 2020年第4期33卷 201-208页

作者： Chang Chen Yun Wang Yongxiang Wei Shuilong Li Qisheng Zhang MWMC Research Group School of Geophysics and Information TechnologyChina University of GeoscienceBeijing 100083China fujian earthquake agency Fuzhou 530001China

Rotational components play an important role in natural earthquake research,engineering seismic investigation,building monitoring,seismic exploration and other *** researches mainly focus on three translational components,but less on rotational *** the precision of rotational sensing techniques has increased,many scholars have paid more attention to the seismic rotational *** the rotational observations are not very popular before and now,approximately converting the translational components into rotational components is utilized in rotation *** on numerical six-component seismic data with the finite difference method,we compare three different conversion methods,the travelling-wave,frequency-domain and the difference method,to analyze their characteristics and feasibilities when they are applied to estimate rotational components with translational observations.

关键词： rotational components travelling-wave method frequency-domain method difference method