龙门山断裂带周缘重复地震识别及其在台网定位评价中的应用
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摘要
利用国家测震台网数据备份中心时间跨度超过7年的连续波形资料,设定至少三个台站记录的垂直分量波形互相关系数大于0.8的地震对为一组重复地震,通过波形互相关分析,识别出龙门山断裂带周缘波形相关意义上的"重复地震"2790次,构成2907组重复地震。沿用Schaff和Richards的研究结果,假定"重复地震"间距很小(小于1 km),地震目录记录的重复地震对位置之差主要为地震台网的定位误差所致,基于此误差给出了龙门山断裂带周缘地震台网的定位精度估计:台网的水平定位精度较高,水平定位误差约为2.8 km(2倍标准差),且西南段台网的水平定位精度优于中北段;垂直定位精度较差,垂直定位误差约为10 km(2倍标准差),现有地震定位方法对震源深度的测定有待改善。
Repeating earthquakes have been used in assessing the location accuracy of the seismograph network for more than a decade. In this study, we used the continuous waveform data recorded by the State Earthquake Information Service Digital Media Center(SEIS DMC) between August 2007 and December 2014 to search for repeating earthquakes along the Longmenshan fault zone(LMSFZ). We obtained 2790 repeating earthquakes by using cross-correlation analysis of waveform data, based on the principle that repeating events should be recorded by at least 3 stations and have a cross-correlation coefficient C>0.8. With the assumption that the repeating events were separated by no more than 1 km, the location difference of repeating earthquakes recorded by seismic catalogue is mainly caused by the positioning error of seismic network. Based on this error, weestimate the positioning accuaracy of seismic network around Longmenshan fault zone. It is observed that the "horizontal location error" of seismograph network near LMSFZ is estimated to be below 5 km, with an average of 2.8 km. And the average location accuracy of the southwestern segment of the LMSFZ is better than that of the central-northern segment. The results also show that the "vertical location error" is estimated to be about 10 km.
Repeating earthquakes have been used in assessing the location accuracy of the seismograph network for more than a decade. In this study, we used the continuous waveform data recorded by the State Earthquake Information Service Digital Media Center(SEIS DMC) between August 2007 and December 2014 to search for repeating earthquakes along the Longmenshan fault zone(LMSFZ). We obtained 2790 repeating earthquakes by using cross-correlation analysis of waveform data, based on the principle that repeating events should be recorded by at least 3 stations and have a cross-correlation coefficient C>0.8. With the assumption that the repeating events were separated by no more than 1 km, the location difference of repeating earthquakes recorded by seismic catalogue is mainly caused by the positioning error of seismic network. Based on this error, weestimate the positioning accuaracy of seismic network around Longmenshan fault zone. It is observed that the "horizontal location error" of seismograph network near LMSFZ is estimated to be below 5 km, with an average of 2.8 km. And the average location accuracy of the southwestern segment of the LMSFZ is better than that of the central-northern segment. The results also show that the "vertical location error" is estimated to be about 10 km.
引文
[1] Isacks B L,Sykes L R,Oliver J.Spatial and temporal clustering of deep and shallow earthquakes in the Fiji-Tonga-Kermadec region[J].Bulletin of Seismological Society of America,1967,57(5):935-958.
[2] Poupinet G,Ellsworth W L,Frechet J.Monitoring velocity variations in the crust using earthquake doublets:An application to the Calaveras Fault,California[J].Journal of Geophysics Research,1984,89(B7):5719-5731.
[3] Schaff D P,Richards P G.Repeating seismic events in China[J].Science,2004,303(5661):1176-1178.
[4] Nadeau R M,Foxall W,McEvilly T V.Clustering and periodic recurrence of microearthquakes on the San Andreas fault at Parkfield,California[J].Science,1995,267(5197):503-507.
[5] Vidale J E,Ellsworth W,Cole A,et al.Variations in rupture process with recurrence interval in a repeated small earthquake[J].Nature,1994,368(6472):624-626.
[6] Khoshmanesh M,Shirzaei M,Nadeau R M.Time-dependent model of aseismic slip on the central San Andreas Fault from InSAR time series and repeating earthquakes[J].Journal of Geophysical Research,2015,120(9):6658-6679.
[7] Li L,Chen Q F,Niu F L,et al.Deep slip rates along the Longmen Shan fault zone estimated from repeating microearthquakes[J].Journal of Geophysical Research,2011,116 (B9):B09310.
[8] Schaff D P,Beroza G C.Coseismic and postseismic velocity changes measured by repeating earthquakes[J].Journal of Geophysics Research,2004,109(B10):B10302.
[9] Zhao P,Peng Z G.Depth extent of damage zones around the central Calaveras fault from waveform analysis of repeating earthquakes[J].Geophysical Journal International,2009,179(3):1817-1830.
[10] Li L,Niu F L,Chen Q F,et al.Post-seismic velocity changes along the 2008 M7.9 Wenchuan earthquake rupture zone revealed by S coda of repeating events[J].Geophysical Journal International,2017,208(2):1237-1249.
[11] Nadeau R M,McEvilly T V.Fault slip rates at depth from recurrence intervals of repeating microearthquakes[J].Science,1999,285(5428):718-721.
[12] Nadeau R M,McEvilly T V.Periodic pulsing of characteristic microearthquakes on the San Andreas fault[J].Science,2004,303(5655):220-222.
[13] Schmittbuhl J,Karabulut H,Lengliné O,et al.Long-lasting seismic repeaters in the Central Basin of the Main Marmara Fault[J].Geophysical Research Letters,2016,43(18):9527-9534.
[14] Schaff D P,Waldhauser F.Waveform Cross-Correlation-Based Differential Travel-Time Measurements at the Northern California Seismic Network[J].Bulletin of Seismological Society of America,2005,95(6):2446-2461.
[15] Jiang C S,Wu Z L,Li Y T,et al.“Repeating events” as estimator of location precision:The China national seismograph network[J].Pure and Applied Geophysics,2014,171(3-5):413-423.
[16] Matsuzawa T,Igarashi T,Hasegawa A.Characteristic smallearthquake sequence off Sanriku,northeastern Honshu,Japan[J].Geophysical Research Letters,2002,29(11):38-1-38-4.
[17] Thomas A M,Beroza G C,Shelly D R.Constraints on the source parameters of low-frequency earthquakes on the San Andreas Fault[J].Geophysical Research Letters,2016,43(4):1464-1471.
[18] 刘瑞丰,高景春,陈运泰,等.中国数字地震台网的建设与发展[J].地震学报,2008,30(5):533-539.
[19] 蒋长胜,吴忠良,李宇彤.首都圈地区“重复地震”及其在区域地震台网定位精度评价中的应用[J].地球物理学报,2008,51(3):817-827.
[20] 邓起东,陈社发,赵小麟.龙门山及其邻区的构造和地震活动及动力学[J].地震地质,1994,16(4):389-403.
[21] 李勇,黄润秋,周荣军,等.龙门山地震带的地质背景与汶川地震的地表破裂[J].工程地质学报,2009,17(1):3-18.
[22] Dziewonski A M,Anderson D L.Preliminary reference Earth model[J].Physics of the Earth and Planetary Interiors,1981,25(4):297-356.
[23] B?th M.Spectral Analysis in Geophysics[M].Amsterdam:Elsevier Scientific Publishing Company,1974,87-94.
[24] 高原,周蕙兰,郑斯华,等.测定震源深度的意义的初步讨论[J].中国地震,1997,13(4):321-329.
[25] 郭飙,刘启元,陈九辉,等.首都圈数字地震台网的微震定位实验[J].地震地质,2002,24(3):453-460.
[26] 宋美琴,郑勇,葛粲,等.山西地震带中小震精确位置及其显示的山西地震构造特征[J].地球物理学报,2012,55(2):513-525.
[27] 陈棋福,李乐.2008年汶川地震与龙门山断裂带的深浅部变形及启示[J].科学通报,2018,63(19):1917-1933.
[2] Poupinet G,Ellsworth W L,Frechet J.Monitoring velocity variations in the crust using earthquake doublets:An application to the Calaveras Fault,California[J].Journal of Geophysics Research,1984,89(B7):5719-5731.
[3] Schaff D P,Richards P G.Repeating seismic events in China[J].Science,2004,303(5661):1176-1178.
[4] Nadeau R M,Foxall W,McEvilly T V.Clustering and periodic recurrence of microearthquakes on the San Andreas fault at Parkfield,California[J].Science,1995,267(5197):503-507.
[5] Vidale J E,Ellsworth W,Cole A,et al.Variations in rupture process with recurrence interval in a repeated small earthquake[J].Nature,1994,368(6472):624-626.
[6] Khoshmanesh M,Shirzaei M,Nadeau R M.Time-dependent model of aseismic slip on the central San Andreas Fault from InSAR time series and repeating earthquakes[J].Journal of Geophysical Research,2015,120(9):6658-6679.
[7] Li L,Chen Q F,Niu F L,et al.Deep slip rates along the Longmen Shan fault zone estimated from repeating microearthquakes[J].Journal of Geophysical Research,2011,116 (B9):B09310.
[8] Schaff D P,Beroza G C.Coseismic and postseismic velocity changes measured by repeating earthquakes[J].Journal of Geophysics Research,2004,109(B10):B10302.
[9] Zhao P,Peng Z G.Depth extent of damage zones around the central Calaveras fault from waveform analysis of repeating earthquakes[J].Geophysical Journal International,2009,179(3):1817-1830.
[10] Li L,Niu F L,Chen Q F,et al.Post-seismic velocity changes along the 2008 M7.9 Wenchuan earthquake rupture zone revealed by S coda of repeating events[J].Geophysical Journal International,2017,208(2):1237-1249.
[11] Nadeau R M,McEvilly T V.Fault slip rates at depth from recurrence intervals of repeating microearthquakes[J].Science,1999,285(5428):718-721.
[12] Nadeau R M,McEvilly T V.Periodic pulsing of characteristic microearthquakes on the San Andreas fault[J].Science,2004,303(5655):220-222.
[13] Schmittbuhl J,Karabulut H,Lengliné O,et al.Long-lasting seismic repeaters in the Central Basin of the Main Marmara Fault[J].Geophysical Research Letters,2016,43(18):9527-9534.
[14] Schaff D P,Waldhauser F.Waveform Cross-Correlation-Based Differential Travel-Time Measurements at the Northern California Seismic Network[J].Bulletin of Seismological Society of America,2005,95(6):2446-2461.
[15] Jiang C S,Wu Z L,Li Y T,et al.“Repeating events” as estimator of location precision:The China national seismograph network[J].Pure and Applied Geophysics,2014,171(3-5):413-423.
[16] Matsuzawa T,Igarashi T,Hasegawa A.Characteristic smallearthquake sequence off Sanriku,northeastern Honshu,Japan[J].Geophysical Research Letters,2002,29(11):38-1-38-4.
[17] Thomas A M,Beroza G C,Shelly D R.Constraints on the source parameters of low-frequency earthquakes on the San Andreas Fault[J].Geophysical Research Letters,2016,43(4):1464-1471.
[18] 刘瑞丰,高景春,陈运泰,等.中国数字地震台网的建设与发展[J].地震学报,2008,30(5):533-539.
[19] 蒋长胜,吴忠良,李宇彤.首都圈地区“重复地震”及其在区域地震台网定位精度评价中的应用[J].地球物理学报,2008,51(3):817-827.
[20] 邓起东,陈社发,赵小麟.龙门山及其邻区的构造和地震活动及动力学[J].地震地质,1994,16(4):389-403.
[21] 李勇,黄润秋,周荣军,等.龙门山地震带的地质背景与汶川地震的地表破裂[J].工程地质学报,2009,17(1):3-18.
[22] Dziewonski A M,Anderson D L.Preliminary reference Earth model[J].Physics of the Earth and Planetary Interiors,1981,25(4):297-356.
[23] B?th M.Spectral Analysis in Geophysics[M].Amsterdam:Elsevier Scientific Publishing Company,1974,87-94.
[24] 高原,周蕙兰,郑斯华,等.测定震源深度的意义的初步讨论[J].中国地震,1997,13(4):321-329.
[25] 郭飙,刘启元,陈九辉,等.首都圈数字地震台网的微震定位实验[J].地震地质,2002,24(3):453-460.
[26] 宋美琴,郑勇,葛粲,等.山西地震带中小震精确位置及其显示的山西地震构造特征[J].地球物理学报,2012,55(2):513-525.
[27] 陈棋福,李乐.2008年汶川地震与龙门山断裂带的深浅部变形及启示[J].科学通报,2018,63(19):1917-1933.
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