2008年汶川大地震临震前震中附近是否存在显著的地壳垂直运动？

doi:10.3969/j.issn.0253-4967.2014.04.002

摘要/Abstract

摘要：

2008年5月12日的汶川M_S 8.0地震是自1976年唐山地震以来发生在中国大陆的最大灾难事件.地震发生后有人通过对GPS数据的动态处理分析认为在地震前1小时内震中附近有非常显著的地壳垂直运动发生, 从而提升了地震学界对通过高频GPS观测技术实现地震短临预报的预期.高频GPS观测技术是近年来GPS技术发展的一个重要方面, 在研究地震前后地壳形变短期变化过程、地震震源破裂过程等方面取得了非常广泛的应用, 但数据解算的精度和可靠性还是受到多种因素的制约.文中提出了一种基于数据静态处理得到的载波相位观测残差来分析测站位置动态变化的方法, 并采用这种方法对汶川地震前震中附近几个GPS连续站的数据进行分析, 结果表明汶川地震前震中附近并不存在显著的地壳运动.

关键词: GPS, 静态/动态数据处理, 汶川地震, 地壳垂向形变

Abstract:

The May 12, 2008 M_S 8.0 Wenchuan earthquake has been the greatest catastrophic event occurring in China since the 1976 Tangshan earthquake. Following the earthquake, GPS data observed in the epicentral region were analyzed, and one study, based on analysis of independent 30s interval's instantaneous positions, claimed that significant vertical crustal displacement occurred one hour prior to the earthquake. This result has raised community expectations to achieve short-term and imminent earthquake prediction using the technique of high-rate GPS monitoring. High-rate GPS is an important technique developed in recent years, and has been widely used for studying short term crustal deformation during an earthquake and earthquake rupture process. Its precision and reliability of data analysis result, however, is constrained by a variety of factors, in particular, the cycle-slip detection and the integer ambiguity resolution of carrier phase are strongly dependent on the distance between the observation site and reference site (for double-differencing analysis) or satellite ephemeris and clock errors (for non-differencing analysis). We propose a new method to analyze dynamic displacements of GPS sites based on carrier phase residuals obtained from static GPS data processing. Assuming that an observation station moves during a time period in which the data are processed, the carrier phase residuals of static data post-processing are mainly reflecting the position displacements and multipath effect. Taking advantage of periodic repeatability of the multipath effect in a sidereal day, we develop a model to reduce/remove the multipath component in the carrier phase residuals, and extract the observation station dynamic displacement signals relative to the station mean position. We apply this method to derive the dynamic displacement time series of 3 continuous GPS stations (CHDU, PIXI, and DUJY) located in the epicentral region of the Wenchuan earthquake. Our result shows that vertical displacements of the 3 sites within 7 days prior to the earthquake are within 2cm, and the disturbances appear to be random than progressive. The resolved dynamic displacements in two consecutive days are also shown to be highly correlated, suggesting that there was no significant disturbance caused by external error source or deformation source. This conclusion is true also for the day (and even one hour) prior to the earthquake. Combining with the analysis of the coseismic deformation pattern, we conclude that there was no significant crustal motion in the epicentral region prior to the Wenchuan earthquake.

Key words: GPS, static/dynamic data processing, Wenchuan earthquake, vertical crustal deformation

中图分类号:

P315.72⁺5

王敏, 沈正康. 2008年汶川大地震临震前震中附近是否存在显著的地壳垂直运动？[J]. 地震地质, 2014, 36(4): 956-963.

WANG Min, SHEN Zheng-kang. WAS THERE SIGNIFICANT VERTICAL CRUSTAL MOTION IN EPICENTRAL REGION PRIOR TO 2008 GREAT WENCHUAN EARTHQUAKE？[J]. SEISMOLOGY AND GEOLOGY, 2014, 36(4): 956-963.

参考文献

方荣新, 施闯, 魏娜, 等. 2009. GPS数据质量控制中实时周跳探测研究［J］. 武汉大学学报(信息科学版), 34(9): 1094—1097.
FANG Rong-xin, SHI Chuang, WEI Na, et al. 2009. Real-time cycle-slip detection for quality control of GPS measurements ［J］. Geomatics and Information Science of Wuhan University, 34(9): 1094—1097(in Chinese).
顾国华, 孟国杰, 方颖. 2011. 汶川大地震前后GPS观测的精密单历元解得到的震区地壳运动［J］. 地震学报, 33(3): 319—326.
GU Guo-hua, MENG Guo-jie, FANG Ying. 2011. Crustal movement in the earthquake area before and after 2008 Wenchuan earthquake as detected by precise single epoch positioning of GPS observations ［J］. Acta Seismologica Sinica, 33(3): 319—326(in Chinese).
王敏. 2009. 基于GPS同震位移场约束反演2008年5.12汶川大地震破裂空间分布［J］. 地球物理学报, 52(10): 2519—2526. doi: 10.3969/J.issn.0001-5733.2009.10.010.
WANG Min. 2009. Coseismic slip distribution of the 2008 Wenchuan great earthquake constrained using GPS coseismic displacement field ［J］. Chinese Journal Geophysics, 52(10): 2519—2526(in Chinese).
殷海涛, 张培震, 甘卫军, 等. 2010. 高频GPS测定的汶川8.0级地震震时近场地表变形过程［J］. 科学通报, 55(26): 2621—2626. doi: 10.1007/s11434-010-4026-2.
YIN Hai-tao, ZHANG Pei-zhen, GAN Wei-jun, et al. 2010. Near-field surface movement during the Wenchuan M_S8.0 earthquake measured by high-rate GPS ［J］. Chinese Science Bulletin, 55(23): 2529—2534.
张小红, 李星星. 2010. 非差模糊度整数固定解PPP新方法及实验［J］. 武汉大学学报(信息科学版), 35(6): 657—660.
ZHANG Xiao-hong, LI Xing-xing. 2010. A new method for zero-differenced integer ambiguity resolution and its application to PPP ［J］. Geomatics and Information Science of Wuhan University, 35(6): 657—660(in Chinese).
Bock Y, Prawirodirdjo L, Melbourne T I. 2004. Detection of arbitrarily large dynamic ground motions with a dense high-rate GPS network ［J］. Geophys Res Lett, 31:L06604. doi: 10.1029/2003GL019150.
Choi K, Bilich A, Larson K M, et al. 2004. Modified sidereal filtering: Implication for high-rate GPS positioning ［J］. Geophys Res Lett, 31:L24610. doi: 10.1029/2004GL021621.
Crowell B W, Bock Y, Melgar D. 2012. Real-time inversion of GPS data for finite fault modeling and rapid hazard assessment ［J］. Geophys Res Lett, 39:L9305. doi: 10.1029/2012GL051318.
Ge L, Han S, Rizos C. 2000. Multipath mitigation of continuous GPS measurements using an adaptive filter ［J］. GPS Solutions, 4(2):19—30. doi: 10.1007/PL00012838.
Petit G, Luzum B. 2010. IERS Conventions(2010): IERS Technical Note 36 ［M］. Verlagdes Bundesamts für Kartographie und Geodäsie, Frankfurt am Main, Germany.
Herring T A, King R W, McClusky S C. 2010. GAMIT Reference Manual, Release 10.4 ［M］. Massachusetts Institute of Technology, Cambridge, MA, America.
Ji C, Larson K M, Tan Y, et al. 2004. Slip history of the 2003 San Simon earthquake constrained by combining 1-Hz GPS, strong motion, and teleseismic data ［J］. Geophys Res Lett, 31:L17608. doi: 10.1029/2004GL020448.
Larson K M, Bodin P, Gomberg J. 2003. Using 1-Hz GPS data to measure deformations caused by the Denali Fault earthquake ［J］. Science, 300(5624): 1421—1424. doi: 10.1126/science.1084531.
Liu Z. 2011. A new automated cycle slip detection and repair method for a single dual-frequency GPS receiver ［J］. Journal of Geodesy, 85: 171—183. doi: 10.1007/s00190-010-0426-y.
Melbourne W G. 1985. The case for ranging in GPS based geodetic systems ［C］. In: Proceedings of the First International Symposium on Precise Positioning with the Global Positioning System, Rockville, April 15-19, 373—386.
Shen Z K, King R W, Agnew D C, et al. 2011. A unified analysis of crustal motion in Southern California, 1970-2004: The SCEC crustal motion map ［J］. J Geophys Res, 116:B11402. doi: 10.1029/2011JB008549.
Shen Z K, Sun J B, Zhang P Z, et al. 2009. Slip maxima at fault junctions and rupturing of barriers during the 2008 Wenchuan earthquake ［J］. Nature Geoscience, 2: 718—724. doi: 10.103.8/ngeo636.
Steigenberger P, Rothacher M, Dietrich R, et al. 2006. Reprocessing of a global GPS network ［J］. J Geophys Res, 111:B05402. doi: 10.1029/2005JB003747.
Wübbena G. 1985. Software developments for geodetic positioning with GPS using TI4100 code and carrier measurements ［C］. In: Proceedings of the First International Symposium on Precise Positioning with the Global Positioning System, Rockville, April 15-19, 403—412.

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