汶川M_S 8.0地震前InSAR垂直形变场变化特征研究
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摘要
利用D-InSAR技术,选用汶川地震前日本ALOS/PALSAR数据,提取了汶川地震前4个条带的形变场,形变场覆盖了映秀镇、茂县、北川县、平武和青川县.结果显示,汶川地震前形变场沿断层呈"凸"状对称形变分布特征,沿发震断层附近出现隆起形变,而远离发震断层两盘均出现下沉,且随着远离断层距离的增加,沉降幅度逐步增加.在断层两侧附近的平武、北川、安县、江油一带出现了大面积形变隆起,幅度为5～10 cm,且断层西侧抬升范围大于东侧.在映秀镇和汶川地震震中附近,沿断层两侧呈现出小范围斑块状隆起,范围在10～15 cm.该隆起区域与汶川震中位置和破裂最强烈段落基本一致.在远离断层的两盘区域出现沉降,绵阳至成都一带沉降范围在0～-10 cm之间,松潘至文县一带沉降范围在-5～-10 cm之间.研究表明对于处于闭锁阶段的逆冲断层,震前的垂直变形可能是其主要变形特征.虽然获得的震前形变变化可能存在5 cm的DEM和对流层大气延迟造成的误差,但这种震前垂直形变场变化趋势仍然存在,可能为地震监测预报提供科学依据.
Using the D-InSAR technology, we have analyzed the Japanese satellite ALOS/ PLASAR data before the 2008 Wenchuan earthquake and obtained four zones of ground deformation which cover the Yingxiu town, Maoxian county, Beichuan county, Pingwu and Qingchuan county in Sichuan Province. The result shows that before the Wenchuan event, the deformation field was a symmetric convex-shaped pattern around the fault. Vertical uplift appeared nearby the seismogenic fault, while subsidence took place far on its both sides away from the fault which increased in amplitude with increasing distance from the fault. Around Pingwu, Beichuan, Anxian and Jiangyou, a large area of uplift was present on the both sides of the fault with amplitude 5～10 cm. Nearby the Yingxiu town and the epicenter of the main shock, small scale spot-like swelling of 10～15 cm occurred separately, which coincides with the location of the epicenter as well as the most obvious rupture section. In the areas far away from the fault on both sides, there was dominantly subsidence, which was measured 0～-10 cm around Mianyang and Chengdu City and -5～-10 cm from Songpan to Wenxian, respectively. Our study indicates that along the locked thrust fault, vertical uplift is its primary characteristic before the quake. Although the derived deformation before the Wechchuan event from this work probably contains errors of 5 cm related with DEM and the atmospheric delay in the troposphere, such an abnormal change in the vertical deformation field indeed existed which can serve as a line of evidence for earthquake prediction.
Using the D-InSAR technology, we have analyzed the Japanese satellite ALOS/ PLASAR data before the 2008 Wenchuan earthquake and obtained four zones of ground deformation which cover the Yingxiu town, Maoxian county, Beichuan county, Pingwu and Qingchuan county in Sichuan Province. The result shows that before the Wenchuan event, the deformation field was a symmetric convex-shaped pattern around the fault. Vertical uplift appeared nearby the seismogenic fault, while subsidence took place far on its both sides away from the fault which increased in amplitude with increasing distance from the fault. Around Pingwu, Beichuan, Anxian and Jiangyou, a large area of uplift was present on the both sides of the fault with amplitude 5～10 cm. Nearby the Yingxiu town and the epicenter of the main shock, small scale spot-like swelling of 10～15 cm occurred separately, which coincides with the location of the epicenter as well as the most obvious rupture section. In the areas far away from the fault on both sides, there was dominantly subsidence, which was measured 0～-10 cm around Mianyang and Chengdu City and -5～-10 cm from Songpan to Wenxian, respectively. Our study indicates that along the locked thrust fault, vertical uplift is its primary characteristic before the quake. Although the derived deformation before the Wechchuan event from this work probably contains errors of 5 cm related with DEM and the atmospheric delay in the troposphere, such an abnormal change in the vertical deformation field indeed existed which can serve as a line of evidence for earthquake prediction.
引文
[1] Gan W, Zhang P, Shen Z K, et al. Present-day crustal motion within the Tibetan Plateau inferred from GPS measurements. J. Geophys. Res. , 2007, 112, B08416, doi: 10． 1029/2005JB004120
[2] 江在森,方颖,武艳强等.汶川8． 0级地震前区域地壳运动与变形动态过程.地球物理学报,2009,52(2) :505-518 Jiang Z S,Fang Y, Wu Y Q, et al. The dynamic process of regional crustal movement and deformation before Wenchuan M_S8． 0 earthquake.Chinese J. Geophys. (in Chinese), 2009, S2(2) :505-518
[3] 郭增建,秦保燕(主编).地震成因和地震预报.北京:地震出版社,1991 Guo Z J, Qin B Y eds. Earthquake Mechanism and Prediction (in Chinese). Beijing: Seismological Press, 1991
[4] Shan X J, Zhang G H. A characteristic analysis of dynamic evolution of preseismic-coseismic-postseismic interferometric deformation fields associated with the Ml. 9 earthquake of Mani, Tibet in 1997． Acta Geological Sinica ( English Edition), 2007, 81(4) :587-592
[5] 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.地震地质,1994,16(4) :389-403 Deng Q D, Chen S F, Zhao X L. Tectonics, seismisity and dynamics of Longmenshan mountains and its adjacent regions. Seismology and Geology (in Chinese), 1994, 16 (4) :389-403
[6] 徐锡伟,张培震,闻学泽等.川西及其邻区活动构造基本特征与强震复发模型.地震地质,2005,27(3) :446-461 Xu X W, Zhang P Z, Wen X Z, et al. Features of active tectonics and recurrence behaviors of strong earthquakes in the western Sichuan province and its adjacent regions. Seismology and Geology (in Chinese), 2005,27(3) :446-461
[7] 李传友,宋方敏,冉勇康.龙门山断裂带北段晚第四纪活动性讨论.地震地质,2004,26(2) :248-257 Li C Y, Song F M, Ran Y K. Late quaternary activity and age constraint of the northern Longmenshan fault zone. Seismology and Geology (in Chinese), 2004,26(2) :248-257
[8] 张培震,徐锡伟,闻学泽等.2008年汶川8． 0级地震发震断裂的滑动速率、复发周期和构造成因.地球物理学报,2008,51(4) :1066-1073 Zhang P Z, Xu X W, Wen X Z, et al. Slip rates and recurrence intervals of the Longmen Shan active fault zone, and tectonic implications for the mechanism of the May 12 Wenchuan earthquake, 2008, Sichuan, China. Chinese J.Geophys. (in Chinese) , 2008,51(4) :1066-1073
[9] Xu X W, Wen X Z, Yu G H,et al. Coseismic reverse-and oblique-slip surface faulting generated by the 2008 M_W7． 9 Wenchuan earthquake, China. Geology, 2009, 37(6) :515- 518
[10] 付碧宏,时丕龙,王 萍等.2008年汶川地震断层北川段的几何学与运动学特征及地震地质灾害效应.地球物理学报,Fu B H, Shi P L, Wang P, et al. Geometry and kinematics of the 2008 Wenchuan earthquake surface ruptures around the Qushan Town of Beichuan County, Sichuan: Implications for mitigation of seismic and geologic disasters. Chinese J.Geophys. (in Chinese), 2009,52(2) :485-495
[11] Ding X L, Li Z W, Zhu J J, et al. Atmospheric effects on InSAR measurements and their mitigation. Sensors, 2008, 8: 5426-5448; DOI:10． 3390/s8095426
[12] 王华.InSAR大气延迟误差分析.地理空间信息,2009,7(2) :9-11 Wang H. Analysis on InSAR atmospheric delay errors. Geospatial Information (in Chinese) ,2009,7(2) -9-11
[13] Rose P A,Hensley S,Zebker H A,et al. Surface deformation and coherence measurements of Kilauea volcano, Hawaii,from SIR-C radar interferometry. J. Geophys, Res. , 1996,10KE10) :23109-23125
[14] 薄万举,杨国华,张风霜.汶川M_S8． 0地震孕震机理的形变证据与模型推演.地震,2009,29(1) .85-91 Bo W J, Yang G H, Zhang F S. Deformation evidence and model deduction about the generation mechanism of the Wenchuan M_S8． 0 Earthquake. Earthquake (in Chinese) , 2009,29(1) :85-91
[15] 薄万举,张立成.汶川8． 0级地震的断层形变前兆分析.地震研究,2008,31(增):419-423 Bo W J, Zhang L C. The M_S 8． 0 Wenchuan earthquake: Precursor analysis of fault deformation. Journal of Seismological Research (in Chinese) , 31(Suppl. ) :419-423
[16] 周硕愚,吴云,施顺英等.汶川8． 0级地震前断层形变异常及与其它大震的比较.地震学报,2009,31(2) :140-151 Zhou S Y, Wu Y,Shi S Y, et al. Anomalous change of fault deformation before Wenchuan M_S8． 0 earthquake and its comparison with response of other large earthquakes. Acta Seismologica Sinica(in Chinese), 2009,31(2) :140-151
[17] 单新建,屈春燕,宋小刚等.汶川M_S8． 0级地震InSAR同震形变场观测与研究.地球物理学报,2009,52(2) :496-504 Shan X J, Qu C Y, Song X G, et al. Coseismic surface deformation caused by the Wenchuan M_S8． 0 earthquake from InSAR data analysis. Chinese J. Geophys. (in Chinese), 2009,52(2) :496-504
[2] 江在森,方颖,武艳强等.汶川8． 0级地震前区域地壳运动与变形动态过程.地球物理学报,2009,52(2) :505-518 Jiang Z S,Fang Y, Wu Y Q, et al. The dynamic process of regional crustal movement and deformation before Wenchuan M_S8． 0 earthquake.Chinese J. Geophys. (in Chinese), 2009, S2(2) :505-518
[3] 郭增建,秦保燕(主编).地震成因和地震预报.北京:地震出版社,1991 Guo Z J, Qin B Y eds. Earthquake Mechanism and Prediction (in Chinese). Beijing: Seismological Press, 1991
[4] Shan X J, Zhang G H. A characteristic analysis of dynamic evolution of preseismic-coseismic-postseismic interferometric deformation fields associated with the Ml. 9 earthquake of Mani, Tibet in 1997． Acta Geological Sinica ( English Edition), 2007, 81(4) :587-592
[5] 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.地震地质,1994,16(4) :389-403 Deng Q D, Chen S F, Zhao X L. Tectonics, seismisity and dynamics of Longmenshan mountains and its adjacent regions. Seismology and Geology (in Chinese), 1994, 16 (4) :389-403
[6] 徐锡伟,张培震,闻学泽等.川西及其邻区活动构造基本特征与强震复发模型.地震地质,2005,27(3) :446-461 Xu X W, Zhang P Z, Wen X Z, et al. Features of active tectonics and recurrence behaviors of strong earthquakes in the western Sichuan province and its adjacent regions. Seismology and Geology (in Chinese), 2005,27(3) :446-461
[7] 李传友,宋方敏,冉勇康.龙门山断裂带北段晚第四纪活动性讨论.地震地质,2004,26(2) :248-257 Li C Y, Song F M, Ran Y K. Late quaternary activity and age constraint of the northern Longmenshan fault zone. Seismology and Geology (in Chinese), 2004,26(2) :248-257
[8] 张培震,徐锡伟,闻学泽等.2008年汶川8． 0级地震发震断裂的滑动速率、复发周期和构造成因.地球物理学报,2008,51(4) :1066-1073 Zhang P Z, Xu X W, Wen X Z, et al. Slip rates and recurrence intervals of the Longmen Shan active fault zone, and tectonic implications for the mechanism of the May 12 Wenchuan earthquake, 2008, Sichuan, China. Chinese J.Geophys. (in Chinese) , 2008,51(4) :1066-1073
[9] Xu X W, Wen X Z, Yu G H,et al. Coseismic reverse-and oblique-slip surface faulting generated by the 2008 M_W7． 9 Wenchuan earthquake, China. Geology, 2009, 37(6) :515- 518
[10] 付碧宏,时丕龙,王 萍等.2008年汶川地震断层北川段的几何学与运动学特征及地震地质灾害效应.地球物理学报,Fu B H, Shi P L, Wang P, et al. Geometry and kinematics of the 2008 Wenchuan earthquake surface ruptures around the Qushan Town of Beichuan County, Sichuan: Implications for mitigation of seismic and geologic disasters. Chinese J.Geophys. (in Chinese), 2009,52(2) :485-495
[11] Ding X L, Li Z W, Zhu J J, et al. Atmospheric effects on InSAR measurements and their mitigation. Sensors, 2008, 8: 5426-5448; DOI:10． 3390/s8095426
[12] 王华.InSAR大气延迟误差分析.地理空间信息,2009,7(2) :9-11 Wang H. Analysis on InSAR atmospheric delay errors. Geospatial Information (in Chinese) ,2009,7(2) -9-11
[13] Rose P A,Hensley S,Zebker H A,et al. Surface deformation and coherence measurements of Kilauea volcano, Hawaii,from SIR-C radar interferometry. J. Geophys, Res. , 1996,10KE10) :23109-23125
[14] 薄万举,杨国华,张风霜.汶川M_S8． 0地震孕震机理的形变证据与模型推演.地震,2009,29(1) .85-91 Bo W J, Yang G H, Zhang F S. Deformation evidence and model deduction about the generation mechanism of the Wenchuan M_S8． 0 Earthquake. Earthquake (in Chinese) , 2009,29(1) :85-91
[15] 薄万举,张立成.汶川8． 0级地震的断层形变前兆分析.地震研究,2008,31(增):419-423 Bo W J, Zhang L C. The M_S 8． 0 Wenchuan earthquake: Precursor analysis of fault deformation. Journal of Seismological Research (in Chinese) , 31(Suppl. ) :419-423
[16] 周硕愚,吴云,施顺英等.汶川8． 0级地震前断层形变异常及与其它大震的比较.地震学报,2009,31(2) :140-151 Zhou S Y, Wu Y,Shi S Y, et al. Anomalous change of fault deformation before Wenchuan M_S8． 0 earthquake and its comparison with response of other large earthquakes. Acta Seismologica Sinica(in Chinese), 2009,31(2) :140-151
[17] 单新建,屈春燕,宋小刚等.汶川M_S8． 0级地震InSAR同震形变场观测与研究.地球物理学报,2009,52(2) :496-504 Shan X J, Qu C Y, Song X G, et al. Coseismic surface deformation caused by the Wenchuan M_S8． 0 earthquake from InSAR data analysis. Chinese J. Geophys. (in Chinese), 2009,52(2) :496-504
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