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Moment magnitude of Myanmar earthquake on March 28,2025 from long-period seismic coda 认领 引用 被引量：2
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作者 Tian Li Xiaodong Song 《Earthquake Science》 CAS CSCD 2026年第3期286-293,共8页
On March 28,2025,a large earthquake struck central Myanmar and caused massive damage and casualties.The magnitude of the mainshock is a fundamental parameter that both the general public and scientific communities are... On March 28,2025,a large earthquake struck central Myanmar and caused massive damage and casualties.The magnitude of the mainshock is a fundamental parameter that both the general public and scientific communities are concerned about.The coda moment magnitude(Mwo)is a new and reliable method for determining the magnitude of large earthquakes,using more than 10 hours of long-period coda waves.We determined the Mwo moment magnitude(with one standard error)to be 7.86±0.03 for the Myanmar earthquake,which is generally larger than the previous reports.The determination includes a small correction(0.02)from our systematic evaluation for smaller earthquakes MW<8.3.The Mwo of the Myanmar earthquake is comparable to that of the Kunlun earthquake,and is slightly smaller(0.15±0.03)than that of the 2008 Wenchuan earthquake.The differences are consistent with those from the Global Centroid-Moment-Tensor. 展开更多
关键词 2025 Myanmar earthquake moment magnitude long-period coda wave
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基于主客观赋权CODAS的GNSS观测环境复杂度评估方法 认领 引用
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作者 黄明庄 戴吾蛟 +1 位作者 余文坤 温亚鑫 《大地测量与地球动力学》 CSCD 北大核心 2026年第4期503-509,共7页
针对GNSS高精度定位中观测环境复杂度的量化评估问题,提出一种基于数据完整率、周跳比、伪距多路径误差、载噪比和PDOP等数据质量指标的综合主客观赋权组合距离评估法(CODAS)。基于不同赋权策略,利用CODAS、TOPSIS和VIKOR方法对120个监... 针对GNSS高精度定位中观测环境复杂度的量化评估问题,提出一种基于数据完整率、周跳比、伪距多路径误差、载噪比和PDOP等数据质量指标的综合主客观赋权组合距离评估法(CODAS)。基于不同赋权策略,利用CODAS、TOPSIS和VIKOR方法对120个监测站的观测环境复杂度进行评估,并采用Spearman相关系数衡量各方法评估结果与PPP动态解算精度的相关性。结果表明,相较于单一赋权,综合主客观赋权可提升CODAS方法准确性;CODAS方法的评估结果与均方根误差和平均误差的Spearman相关系数分别为0.897和0.924,优于TOPSIS和VIKOR方法。参数敏感性分析表明,CODAS方法在不同折衷系数下的评估结果标准差均值小于1.5,具备良好的稳定性。 展开更多
关键词 GNSS观测环境复杂度 数据质量分析 CRITIC 综合赋权 CODAS
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转codA基因提高番茄植株的耐热性 认领 引用 被引量：6
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作者 李枝梅 窦海鸥 +3 位作者 卫丹丹 孟庆伟 Tony Huihuang CHEN 杨兴洪 《作物学报》 CAS CSCD 北大核心 2013年第11期2046-2054,共9页
以野生型番茄(cv.Moneymaker)和转codA番茄为材料,用不同温度(25、30、35、40、45和50℃)分别处理2 h,测定叶片净光合速率(Pn)、PSII最大光化学效率(Fv/Fm)、过氧化氢(H2O2)含量、丙二醛(MDA)含量、相对电导率(REC)和抗氧化酶活性等生... 以野生型番茄(cv.Moneymaker)和转codA番茄为材料,用不同温度(25、30、35、40、45和50℃)分别处理2 h,测定叶片净光合速率(Pn)、PSII最大光化学效率(Fv/Fm)、过氧化氢(H2O2)含量、丙二醛(MDA)含量、相对电导率(REC)和抗氧化酶活性等生理指标;42℃高温处理0、3和6 h后,检测热响应基因的表达量以及D1蛋白的含量,研究高温胁迫对上述参数的影响,探讨转codA基因提高番茄叶片耐热性的机制。结果表明,高温胁迫下,转codA基因番茄叶片Pn和Fv/Fm的抑制程度明显低于野生型,H2O2、MDA的积累量以及REC均低于野生型,而且明显增强了过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、过氧化物酶(POD)和抗坏血酸过氧化物酶(APX)的活性。此外,转codA基因番茄叶片中抗氧化酶基因和热胁迫基因的表达水平均高于野生型,而D1蛋白的降解水平低于野生型。转codA基因番茄体内合成的甜菜碱提高了转基因番茄的耐热性,这与提高和维持较高的抗氧化酶活性、促进热激响应基因的表达及减缓D1蛋白的降解等有关。 展开更多
关键词 codA基因 番茄 高温胁迫 耐热性 甜菜碱
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基于CODAS的CBTC车载系统子系统故障风险评估与维修优先级决策方法 认领 引用 被引量：6
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作者 王宗耀 上官伟 +1 位作者 彭聪 师泽斌 《铁道学报》 EI CAS CSCD 北大核心 2023年第8期87-98,共12页
基于通信的列车控制系统(CBTC)是城市轨道交通信号系统的重要组成部分,其中,CBTC车载系统更是CBTC的核心,针对其高精度、精细化的可靠性评估是保证列车安全高效运行的理论基础。提出一种基于CODAS的CBTC车载系统子系统故障风险评估与维... 基于通信的列车控制系统(CBTC)是城市轨道交通信号系统的重要组成部分,其中,CBTC车载系统更是CBTC的核心,针对其高精度、精细化的可靠性评估是保证列车安全高效运行的理论基础。提出一种基于CODAS的CBTC车载系统子系统故障风险评估与维修优先级决策方法,首先对运行采集的故障间隔时间进行拟合,通过K-S检验法选择最优的分布模型,以最优分布模型为基础求解CBTC车载系统及其子系统的可靠度函数曲线,并采用基于弗雷歇距离的曲线相似度表征各类子系统的可靠性影响度;其次,以可靠性影响度、逆平均利用率、故障发生度与故障发生紧急程度构建故障风险评估指标体系,基于熵权法-CODAS(Combinative Distance-based Assessment)对各子系统的故障风险进行评估与排序;同时,以平均维修时间为基础,结合故障风险评估求解过程中获取的各子系统的欧式距离与出租车距离,建立维修优先级决策指标体系,利用熵权法-CODAS确定子系统最优维修顺序;最后,利用北京地铁某线路CBTC车载系统的历史运维数据进行实例分析。该方法能够为实际工作中的维护方案的制定提供理论依据,对于指导CBTC车载系统的可靠性维护具有积极意义。 展开更多
关键词 CBTC车载系统 曲线相似度 CODAS 故障风险评估 维修优先级决策
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利用农杆菌介导法获得转codA基因麻竹再生植株的研究 认领 引用 被引量：10
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作者 张玲 蒋晶 +3 位作者 乔桂荣 刘明英 杨惠琴 卓仁英 《竹子研究汇刊》 北大核心 2012年第1期1-6,14,共6页
温度是影响植物生存和生长发育的基本环境因子之一。大多数植物对低温等都是高度敏感的,低温伤害现象尤为突出,几乎涉及所有的经济植物。因此,改善植物的抗低温冻害的胁迫能力,可以显著提高植物的生长范围、增加产量。codA基因可以增加... 温度是影响植物生存和生长发育的基本环境因子之一。大多数植物对低温等都是高度敏感的,低温伤害现象尤为突出,几乎涉及所有的经济植物。因此,改善植物的抗低温冻害的胁迫能力,可以显著提高植物的生长范围、增加产量。codA基因可以增加植物对低温胁迫的耐受能力,而Rd29A是一种胁迫诱导特异表达启动子,胁迫条件可以快速诱导基因表达,也可以减少由于转基因过量表达带来的不利影响。研究以麻竹花药离体培养的愈伤组织为材料,采用农杆菌介导法,探讨了影响麻竹愈伤组织遗传转化效率的主要因子。结果表明,潮霉素的最佳筛选浓度是25 mg.L-1,预培养时间为3 d,侵染时间为20 min,共培养时间为3 d,乙酰丁香酮的浓度控制在100 mg.L-1时可以有效的提高遗传转化效率。在此基础上对获得的转基因植株进行分子检测,初步表明外源基因codA已经整合到麻竹基因组中。 展开更多
关键词 麻竹 农杆菌介导 codA基因 Rd29A基因
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Reservoir time-lapse variations and coda wave interferometry 认领 引用 被引量：4
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作者 唐杰 李晶晶 +2 位作者 姚振岸 邵婕 孙成禹 《Applied Geophysics》 SCIE CSCD 2015年第2期244-254,276,共11页
Coda waves are multiply scattered waves that arrive much later than the major waves. Small seismic velocity variations are observed in reservoirs because of small variations in reservoir properties, which affect the f... Coda waves are multiply scattered waves that arrive much later than the major waves. Small seismic velocity variations are observed in reservoirs because of small variations in reservoir properties, which affect the first arrivals. Hence, first arrivals cannot be used to detect small seismic velocity variations. However, small variations can be reliably detected by the coda waves because of the amplification owing to multiple scattering. We investigate the ability of coda wave interferometry to detect seismic velocity variations and monitor time-lapse reservoir characteristics using numerical simulations and experimental data. We use the Marmousi II model and finite-difference methods to build model seismic data and introduce small seismic velocity variations in the target layer. We examine the model seismic data before and after the changes and observe the coda waves. We find that velocity changes can be detected by coda wave interferometry and demonstrate that coda wave interferometry can be used in monitoring time- lapse reservoir characteristics. 展开更多
关键词 time-laose coda wave. interferornetrv wave velocity scattering
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Moment magnitudes of two large Turkish earthquakes on February 6,2023 from long-period coda 认领 引用 被引量：8
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作者 Xinyu Jiang Xiaodong Song +1 位作者 Tian Li Kaixin Wu 《Earthquake Science》 2023年第2期169-174,共6页
Two large earthquakes(an earthquake doublet)occurred in south-central Turkey on February 6,2023,causing massive damages and casualties.The magnitudes and the relative sizes of the two mainshocks are essential informat... Two large earthquakes(an earthquake doublet)occurred in south-central Turkey on February 6,2023,causing massive damages and casualties.The magnitudes and the relative sizes of the two mainshocks are essential information for scientific research and public awareness.There are obvious discrepancies among the results that have been reported so far,which may be revised and updated later.Here we applied a novel and reliable long-period coda moment magnitude method to the two large earthquakes.The moment magnitudes(with one standard error)are 7.95±0.013 and 7.86±0.012,respectively,which are larger than all the previous reports.The first mainshock,which matches the largest recorded earthquakes in the Turkish history,is slightly larger than the second one by 0.11±0.035 in magnitude or by 0.04 to 0.18 at 95%confidence level. 展开更多
关键词 2023 Turkish earthquakes coda wave moment magnitude long-period
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Transgenic Brassica chinensis plants expressing a bacterial codA gene exhibit enhanced tolerance to extreme temperature and high salinity 认领 引用 被引量：3
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作者 Qing-bin WANG Wen XU +1 位作者 Qing-zhong XUE Wei-ai SU 《Journal of Zhejiang University-SCIENCE B》 SCIE CAS 2010年第11期851-861,共11页
Transgenic Brassica compestris L.spp.chinensis plants expressing a choline oxidase(codA) gene from Arthrobacter globiformis were obtained through Agrobacterium tumefaciens-mediated transformation.In the transgenic pla... Transgenic Brassica compestris L.spp.chinensis plants expressing a choline oxidase(codA) gene from Arthrobacter globiformis were obtained through Agrobacterium tumefaciens-mediated transformation.In the transgenic plants,codA gene expression and its product transportation to chloroplasts were detected by the enzyme-linked immunosorbent assay(ELISA) examination,immunogold localization,and 1 H-nuclear magnetic resonance( 1 H-NMR) . Stress tolerance was evaluated in the T3 plants under extreme temperature and salinity conditions.The plants of transgenic line 1(L1) showed significantly higher net photosynthetic rate(Pn) and Pn recovery rate under high(45°C,4 h) and low temperature(1°C,48 h) treatments,and higher photosynthetic rate under high salinity conditions(100,200,and 300 mmol/L NaCl,respectively) than the wild-type plants.The enhanced tolerance to high temperature and high salinity stresses in transgenic plants is associated with the accumulation of betaine,which is not found in the wild-type plants.Our results indicate that the introduction of codA gene from Arthrobacter globiformis into Brassica compestris L.spp.chinensis could be a potential strategy for improving the plant tolerance to multiple stresses. 展开更多
关键词 Brassica compestris L. spp. chinensis codA Stress Glycine betaine Net photosynthetic rate （Pn）
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On the generation and decay of the long-period coda energy of large earthquakes 认领 引用 被引量：2
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作者 Xinyu Jiang Xiaodong Song +1 位作者 Han H.Xia Richard L.Weaver 《Earthquake Science》 2021年第2期103-113,共11页
Seismic coda wave is the tail portion of the earthquake record after main arrivals.Studies on the coda usually focus on high-frequency data within several hours after regional events and attribute them to the scatteri... Seismic coda wave is the tail portion of the earthquake record after main arrivals.Studies on the coda usually focus on high-frequency data within several hours after regional events and attribute them to the scattering effect of the heterogeneities inside the earth.Here,we use records of seven large earthquakes at globally distributed seismic stations to examine the decay of long-period(100 s to 300 s)coda in the time window of 10,000 s to 140,000 s after the origin time and fit it with a statistical model.The geometric spreading effect in the estimated initial energy and a locationindependent equivalent attenuation coefficient indicate that the long-period coda energy is less affected by the heterogeneity-induced scattering effect than that of shorterperiod coda.The coda energy can reach the earth’s inner core and can be explained by a 1D earth model,making it more effective for constraining the global attenuation model.It also has the potential to determine the magnitudes of large earthquakes and to explore the interior of planetary bodies. 展开更多
关键词 long-period coda waves large earthquakes geometric spreading attenuation scattering.
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KEF Coda 90、80、70家庭影院音箱系统 认领 引用
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《音响世界》 2002年第9期5-5,共1页
关键词 家庭影院音箱系统 KEF公司 Coda90 Coda80 Coda70 扬声器
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Coda Motion运动分析系统测量健康人颈椎侧屈活动度的准确性分析 认领 引用 被引量：1
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作者 宋辉 高中洋 +4 位作者 赵英杰 高正超 邱晓文 李浩鹏 贺西京 《中国骨伤》 CAS 2018年第11期1017-1021,共5页
目的:探讨Coda Motion运动分析系统测量颈椎侧屈活动度的准确性,为临床及科研实践探索一种新的测量工具。方法:选择43名健康志愿者作为研究对象,采用Coda Motion运动分析系统和"金标准"X线两种工具同时测量其颈椎侧屈活动度... 目的:探讨Coda Motion运动分析系统测量颈椎侧屈活动度的准确性,为临床及科研实践探索一种新的测量工具。方法:选择43名健康志愿者作为研究对象,采用Coda Motion运动分析系统和"金标准"X线两种工具同时测量其颈椎侧屈活动度。运用散点图、皮尔森相关系数r评估Coda Motion运动分析系统测量颈椎侧屈活动度的准确性。结果:Coda Motion运动分析系统与X线测量出的颈椎侧屈活动度差异无统计学意义(P>0.05)。两种工具在测量右侧屈、左侧屈以及总侧屈活动度呈正相关,皮尔森相关系数分别为0.72、0.85和0.90。结论:Coda Motion运动分析系统测量颈椎侧屈活动度的准确性好,可能作为一种新型测量工具用于临床及科研测量颈椎侧屈活动度的实践中。 展开更多
关键词 颈椎活动度 侧屈 Coda Motion运动分析系统
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CODAS系统在厦门湾走航ADCP观测资料质量控制中的应用 认领 引用 被引量：6
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作者 沈俊强 《应用海洋学学报》 CAS CSCD 2014年第4期472-480,共9页
CODAS系统搭配相应质量控制参数,用以识别ADCP在复杂测流环境下测得的可疑或错误流速单元和剖面.通过水跟踪和底跟踪,CODAS系统可有效获取仪器自带数据处理软件vmdas、winriver无法修正的系统误差.本研究采用该系统对厦门湾走航ADCP测... CODAS系统搭配相应质量控制参数,用以识别ADCP在复杂测流环境下测得的可疑或错误流速单元和剖面.通过水跟踪和底跟踪,CODAS系统可有效获取仪器自带数据处理软件vmdas、winriver无法修正的系统误差.本研究采用该系统对厦门湾走航ADCP测量数据做后续质量控制,所得相应系统误差如下:旋转角度偏差Δ=3.2°,幅值修正因子β=0.98.此外,以底跟踪测得流速为准确值,参考GPS数据经过系统误差订正后,流速精度显著提高,平均误差订正前后分别为28.9cm/s和11.6 cm/s.最后,结合现场数据采集工作与数据质量控制过程,总结数据质量问题一般特征并提出改进建议. 展开更多
关键词 物理海洋学 走航ADCP CODAS系统 质量控制 系统误差 厦门湾
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Monitoring Contact State of Laboratory Fault with Coda Transmission Waves 认领 引用 被引量：1
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作者 XIE Fan REN Yaqiong HOU Jinxin 《Earthquake Research in China》 CSCD 2019年第3期431-436,共6页
We monitored the amplitude changes of coda transmission waves around 500 kHz across the frictional interface of a simulated 1. 5-meter-long fault during normal stress holding test.We find that the amplitude of coda tr... We monitored the amplitude changes of coda transmission waves around 500 kHz across the frictional interface of a simulated 1. 5-meter-long fault during normal stress holding test.We find that the amplitude of coda transmission waves increases with the logarithm of stationary contact time. Localized increase amounted to a level ranging from 4% to 16%along the fault is observed during the 1-hour experiment. We discuss that the frictional strength at mesoscopic scale,which is related to the amplitude of coda transmission waves,is responsible for the phenomenon. Combining the reported method with other complementary approaches will enhance the understanding of fault mechanism either at laboratory or on-site applications. 展开更多
关键词 Coda transmission waves Laboratory fault Frictional contact area
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Theoretical researches on three-dimensional coda wave scattering problem 认领 引用 被引量：2
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作者 聂永安 曾健 冯德益 《Acta Seismologica Sinica(English Edition)》 1995年第1期83-87,共5页
Based on the previous researches on scattering theory, a model of single and multiple scattering in a three-dimensional infinite medium with non-zero hypocentral distance is proposed in this paper. According to the as... Based on the previous researches on scattering theory, a model of single and multiple scattering in a three-dimensional infinite medium with non-zero hypocentral distance is proposed in this paper. According to the assumptionof three-dimensional medium with numerous, statistically isotropic and uniformly distributed scatterers, we obtain the analytic form of power spectrum of coda waves for single scattering and the integral form of power spectrum of coda waves for multiple scattering. 展开更多
关键词 coda wave three-dimensional model
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A single-station coda solution for source,attenuation and site factors 认领 引用 被引量：1
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作者 张天中 马云生 黄蓉良 《Acta Seismologica Sinica(English Edition)》 1998年第2期30-37,共8页
ased on the empirical formulation formed from coda observations, the digital waveforms from 33 local events with magnitude ML ranging between 2.1 and 3.5, recorded at Changli station of Beijing Telemetered Sei... ased on the empirical formulation formed from coda observations, the digital waveforms from 33 local events with magnitude ML ranging between 2.1 and 3.5, recorded at Changli station of Beijing Telemetered Seismographic Network from 1989 to 1991, are used to compute coda Q for the Changli region and the source factors of all earthquakes by single-station coda method. Furthermore, assuming a certain source model, we have obtained the station site frequency response and source spectra, as well as source parameters such as corner frequencies, seismic moments and stress drops and so on. Their variations with time are monitored before and after larger earthquakes. Because the coda method can more effectively reduce the influence of source radiation pattern and a particular propagation path than direct wave method, more data can be used and more accurate results can be obtained, which provided a possible approach to study the source properties and reveal the variation of source parameters before larger earthquakes. 展开更多
关键词 coda source factor hypocenter parameter stress drop precursor
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Research on coda Q distribution in Beijing and its surrounding regions 认领 引用 被引量：1
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作者 马云生 张天中 张焕生 《Acta Seismologica Sinica(English Edition)》 1995年第4期551-561,共11页
Based on the single scattering model of seismic coda waves, we have calculated the Q-factor in Beijing and its surrounding regions by means of calculating the power density spectrum in frequency domain with a fixed ti... Based on the single scattering model of seismic coda waves, we have calculated the Q-factor in Beijing and its surrounding regions by means of calculating the power density spectrum in frequency domain with a fixed time window. The digital seismic data of 69 earthquakes from Beijing Telemetered Seismographic Network are used.These earthquakes were recorded from January 1, 1989 to December 31,1990 at 20 stations. This paper shows the variations of the coda Q-factors in the studied region with different sites, frequency and lapse time, and the temporal change of the coda Q-factors in these two years. The results indicate that coda Q-factor depends strongly on the lapse time and frequency. It is assumed that when Qc=Q0f″, for the three time windows of 15 -30 s, 30-60 s and 60-90 s, the average values of Q0 are 48, 115 and 217; and the average values of ηare 0.89, 0. 91 and 0. 74, respectively. 展开更多
关键词 coda wave,quality factor scatter absorption
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CODA全自动酶免分析仪常见故障及处理方法 认领 引用 被引量：1
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作者 许亚辉 《医疗装备》 2004年第12期57-57,共1页
关键词 CODA全自动酶免分析仪 故障现象 医疗器械 医疗设备
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Distribution of Lg coda Q in Xinjiang and its adjacent regions 认领 引用
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作者 徐彦 毛燕 +2 位作者 胡家富 苏有锦 丛连理 《Acta Seismologica Sinica(English Edition)》 2005年第2期162-170,254,共9页
In this study, we collected 1156 broadband vertical components records at 22 digital seismic stations in Xinjiang region, Urumqi station, and 7 stations in the adjacent regions during the period of 1999-2003. The reco... In this study, we collected 1156 broadband vertical components records at 22 digital seismic stations in Xinjiang region, Urumqi station, and 7 stations in the adjacent regions during the period of 1999-2003. The records were firstly processed by the stacked spectral ratio method to obtain Q0 (Q at 1 Hz) and the frequency correlation factor η corresponding to each path. Based on the results, the distribution images of Q0 and η in 1°×1° grids for Xinjiang region were gained by the back-projection technique. The results indicate that Q0 is high (300-450) in the Tarim platform and marginal Siberian platform, while Q0 is low (150-250) in the southern regions as west Kunlun fold system and Songpan-Ganzi fold system. In the northern regions as Junggar fold system and Tianshan fold system, Q0 is also low (250-300) and η varies between 0.5 and 0.9. 展开更多
关键词 Lg coda Q stacked spectral ratio method back-projection technique Xinjiang region
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Lg coda Q_0 value and its relation with the tectonics in Chinese mainland and adjacent regions 认领 引用
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作者 苏伟 吴建平 +1 位作者 明跃红 王椿镛 《Acta Seismologica Sinica(English Edition)》 2006年第2期136-144,共9页
We have collected 432 vertical component records from 45 stations of new CENC （China Earthquake Network Center） in Chinese mainland and adjacent regions. These records were used to calculate Q0 （Q at 1Hz） and η v... We have collected 432 vertical component records from 45 stations of new CENC （China Earthquake Network Center） in Chinese mainland and adjacent regions. These records were used to calculate Q0 （Q at 1Hz） and η values of Lg coda from each station by the stack spectral ratio （SSR） method. Then the tomography method was applied to obtaining lateral variation of Q0 and η values in Chinese mainland and adjacent regions. The result indicates that Q0 value varies between 150 and 600 in the studied areas. Yunnan, southwest Sichuan, and northwest Myanmar show the lowest Q0 value （Q0〈240） and the crust of these regions is characterized by complicated crack and strong hydrothermal activity. The highest Q0 value （Qo〉510） exists in the border of southern Mongolia, Alxa and Ordos block. The η value varies between 0.45 and 0.75 in Chinese mainland and its adjacent regions. 展开更多
关键词 Chinese mainland and adjacent regions Lg coda Q0 value η value
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Regional features of coda attenuation of aftershocks of Wuding, Yunnan earthquake in near field 认领 引用
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作者 秦嘉政 李白基 +3 位作者 钱晓东 苏有锦 蔡静观 付虹 《Acta Seismologica Sinica(English Edition)》 2001年第1期91-100,共10页
According to dispersion theory of coda of local events, using near-field data of aftershocks recorded by two mobile digital stations at the Tianxin and Yunlong after the Wuding, Yunnan Ms=6.5 main-shock and sampling a... According to dispersion theory of coda of local events, using near-field data of aftershocks recorded by two mobile digital stations at the Tianxin and Yunlong after the Wuding, Yunnan Ms=6.5 main-shock and sampling at different central frequencies (1.5-sim;20 Hz), spatial distribution features of coda attenuation ratio β(f) are studied. The results show that there exists obvious non-uniformity of coda attenuation ratio β(f) given by the two stations in small region. When f less than or equal 6.0 Hz the coda attenuation ratio β(f) observed on both sides of earthquake-generating fault are basically identical. Yunlong station is located on east side and Tianxin station on west side. The corresponding Qc(f) is in the range of 66-120. However, in the range of high frequency (f greater than or equal 6.0 Hz) the coda in near field going through major fault encounters a strong absorption from the fracture zone. The β(f) going through the fault observed at Yunlong station is 30% lower than that in Tianxin station in which the seismic waves do not go through the fault. The reason for the difference in space distribution of coda attenuation is discussed. The results also show that factor A0(f) of wave source is not only related to the source strength, but also to frequency f. The mean free path L of S wave obtained using 1.5-20 Hz is respectively 30 km on east side of the fault and 40 km on west side, from which it is verified that there is a stronger dispersion body when seismic waves go through the fracture zone. 展开更多
关键词 coda attenuation in near field space distribution of Qc( f ) local inhomogeneity Wuding earthquake
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