祁连山—六盘山地震带地壳各向异性特征初步研究
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摘要
利用2010年1月至2015年12月甘肃省测震台网的地震波形资料,使用SAM方法,获得了祁连山—六盘山地震带地区21个台站的快剪切波偏振方向和慢剪切波的时间延迟,分析讨论了该地震带地壳介质各向异性空间分布特征。结果表明:大部分台站的快波偏振优势方向明显与区域内的主压应力方向一致,呈近NE-NEE方向,表明来自印度板块和欧亚板块的NNE或NE向的水平挤压应力控制了祁连山—六盘山地震带的中上地壳应力场。但局部区域的快剪切波偏振方向与断裂走向一致,表明该区各向异性具有差异性,主要是由复杂的活动构造所造成。
In this study,the polarization of fast shear waves and time delay of lowshear-wave beneath the 21 stations in this area were computed using shear-wave Splitting Analysis Method( SAM) based on the seismic data during January 2010 to December 2015, recorded by the Gansu Regional Digital Seismic Network. Meanwhile,we also analysed and discussed the spatial distribution of the crust anisotropy characteristics in Qilian Mountains-Liupan Mountains seismic belt. Due to the impact of the regional principal compressive stress and local geological structure,the spatial distribution of polarization of the fast shear-wave shows partly complicated and localized characteristics. The second predominant polarization direction of fast shear-wave is consistent with strike direction of fault in local area,which indicates discreteness and differences about anisotropy. However,the principle polarization direction,which is near NE direction,is obvious in Qilian Mountains-Liupan Mountains seismic belt.
In this study,the polarization of fast shear waves and time delay of lowshear-wave beneath the 21 stations in this area were computed using shear-wave Splitting Analysis Method( SAM) based on the seismic data during January 2010 to December 2015, recorded by the Gansu Regional Digital Seismic Network. Meanwhile,we also analysed and discussed the spatial distribution of the crust anisotropy characteristics in Qilian Mountains-Liupan Mountains seismic belt. Due to the impact of the regional principal compressive stress and local geological structure,the spatial distribution of polarization of the fast shear-wave shows partly complicated and localized characteristics. The second predominant polarization direction of fast shear-wave is consistent with strike direction of fault in local area,which indicates discreteness and differences about anisotropy. However,the principle polarization direction,which is near NE direction,is obvious in Qilian Mountains-Liupan Mountains seismic belt.
引文
柴炽章,马禾青,金春华.2003.祁连山-六盘山地震带中强地震活动特点及震前异常特征[J].西北地震学报,25(4):354-358.
常利军,王椿镛,丁志峰,等.2008.青藏高原东北缘上地幔各向异性研究[J].地球物理学报,51(2):431-438.
崔效锋,谢富仁,赵建涛.2005.中国及邻区震源机制解的分区特征[J].地震地质,27(2):298-307.
邓起东,张培震,冉勇康,等.2002.中国活动构造基本特征[J].中国科学:地球科学,32(12):1020-1030.
丁志峰,武岩,王辉,等.2008.2008年汶川地震震源区横波分裂的变化特征[J].中国科学:地球科学,53(12):1600-1604.
高原,刘希强,梁维,等.2004.剪切波分裂系统分析方法(SAM)软件系统[J].中国地震,20(1):101-107.
高原,石玉涛,梁维,等.2008a.剪切波分裂分析系统SAM(2007)---软件系统[J].中国地震,24(4):345-353.
高原,吴晶.2008b.利用剪切波各向异性推断地壳主压应力场:以首都圈地区为例[J].科学通报,53(23):2933-2939.
高原,郑斯华.1994.唐山地区剪切波分裂研究(Ⅱ)-相关函数分析法[J].中国地震,(增刊1):11-21.
郭桂红,张智,程建武,等.2015.青藏高原东北缘地壳各向异性的构造含义[J].地球物理学报,58(11):4092-4105.
姜永涛,张永志,吴然,等.2015.青藏高原东缘地应变演化特征[J].地震工程学报,37(1):152-158.
李金,高原,徐甫坤,等.2015.2014年5月30日盈江6.1级地震序列剪切波分裂研究[J].中国地震,31(2):245-252.
石玉涛,高原,吴晶,等.2008.剪切波分裂分析系统SAM(2007)---区域地震台网资料应用实例[J].中国地震,24(4):354-361.
王琼,高原,石玉涛,等.2013.青藏高原东北缘上地幔地震各向异性:来自SKS、PKS和SKKS震相分裂的证据[J].地球物理学报,56(3):892-905.
王学潮,郭启良,张辉,等.2000.青藏高原东北缘水压致裂地应力测量[J].地质力学学报,6(2):64-70.
吴晶,高原,石玉涛,等.2010.基于地壳介质各向异性分析江苏及邻区构造应力特征[J].地球物理学报,53(7):1622-1630.
谢富仁,崔效锋,赵建涛,等.2004.中国大陆及邻区现代构造应力场分区[J].地球物理学报,47(4):654-662.
许忠淮.2001.东亚地区现今构造应力图的编制[J].地震学报,23(5):492-501.
袁道阳,张培震,刘百篪,等.2004.青藏高原东北缘晚第四纪活动构造的几何图像与构造转换[J].地质学报,78(2):270-278.
张辉,高原,石玉涛,等.2012.基于地壳介质各向异性分析青藏高原东北缘构造应力特征[J].地球物理学报,55(1):95-104.
张辉.2007.青藏高原东北缘基于小震震源机制解的区域应力场特征研究[D].兰州:中国地震局兰州地震研究所.
CRAMPIN S,BOOTH D C.1985.Shear-wave polarizations near the North Anatolian Fault-II.Interpretation in terms of crack-induced anisotropy[J].Geophysical Journal International,83(1):75-92.
CRAMPIN S,PACOCK S.2005.A review of shear-wave splitting in the compliant crack-critical anisotropic Earth[J].Wave Motion,41(1):59-77.
CRAMPIN S,VOLTI T,STEFANSSON R.1999.A successfully stressforecast earthquake[J].Geophysical Journal International,138(1):1-5.
CRAMPIN S,VOLYI T,CHASTIN S,et al.2002.Indication of high pore-fluid pressures in a seismically-active fault zone[J].Geophysical Journal International,151(2):1-5.
CRAMPIN S.1981.Review of wave motion in anisotropic and cracked media[J].Wave Motion,3(4):343-391.
CRAMPIN S.1984.Effective anisotropic elastic constants for wave propagation through cracked solids[J].Geophysical Journal of the Royal Astronomical Society,76(1):135-145.
GAO Y,CRAMPIN S.2004.Observations of stress relaxation before earthquakes[J].Geophysical Journal International,157(2):578-582.
GAO Y,WANG P,ZHENG S,et al.1998.Temporal changes in shearwave splitting at an isolated swarm of small earthquakes in 1992 near Dongfang,Hainan Island,southern China[J].Geophysical Journal International,135(1):102-112.
TAPPONNIER P,ZHIQIN X,ROGER F,et al.2001.Oblique stepwise rise and growth of the Tibet plateau[J].Science,294(5547):1671-1677.
WU J,ZHANG Z,KONG F,et al.2015.Complex seismic anisotropy beneath western Tibet and its geodynamic implications[J].Earth and Planetary Science Letters,413:167-175.
XU T,WU Z,ZHANG Z,et al.2014.Crustal structure across the Kunlun fault from passive source seismic profiling in East Tibet[J].Tectonophysics,627:98-107.
常利军,王椿镛,丁志峰,等.2008.青藏高原东北缘上地幔各向异性研究[J].地球物理学报,51(2):431-438.
崔效锋,谢富仁,赵建涛.2005.中国及邻区震源机制解的分区特征[J].地震地质,27(2):298-307.
邓起东,张培震,冉勇康,等.2002.中国活动构造基本特征[J].中国科学:地球科学,32(12):1020-1030.
丁志峰,武岩,王辉,等.2008.2008年汶川地震震源区横波分裂的变化特征[J].中国科学:地球科学,53(12):1600-1604.
高原,刘希强,梁维,等.2004.剪切波分裂系统分析方法(SAM)软件系统[J].中国地震,20(1):101-107.
高原,石玉涛,梁维,等.2008a.剪切波分裂分析系统SAM(2007)---软件系统[J].中国地震,24(4):345-353.
高原,吴晶.2008b.利用剪切波各向异性推断地壳主压应力场:以首都圈地区为例[J].科学通报,53(23):2933-2939.
高原,郑斯华.1994.唐山地区剪切波分裂研究(Ⅱ)-相关函数分析法[J].中国地震,(增刊1):11-21.
郭桂红,张智,程建武,等.2015.青藏高原东北缘地壳各向异性的构造含义[J].地球物理学报,58(11):4092-4105.
姜永涛,张永志,吴然,等.2015.青藏高原东缘地应变演化特征[J].地震工程学报,37(1):152-158.
李金,高原,徐甫坤,等.2015.2014年5月30日盈江6.1级地震序列剪切波分裂研究[J].中国地震,31(2):245-252.
石玉涛,高原,吴晶,等.2008.剪切波分裂分析系统SAM(2007)---区域地震台网资料应用实例[J].中国地震,24(4):354-361.
王琼,高原,石玉涛,等.2013.青藏高原东北缘上地幔地震各向异性:来自SKS、PKS和SKKS震相分裂的证据[J].地球物理学报,56(3):892-905.
王学潮,郭启良,张辉,等.2000.青藏高原东北缘水压致裂地应力测量[J].地质力学学报,6(2):64-70.
吴晶,高原,石玉涛,等.2010.基于地壳介质各向异性分析江苏及邻区构造应力特征[J].地球物理学报,53(7):1622-1630.
谢富仁,崔效锋,赵建涛,等.2004.中国大陆及邻区现代构造应力场分区[J].地球物理学报,47(4):654-662.
许忠淮.2001.东亚地区现今构造应力图的编制[J].地震学报,23(5):492-501.
袁道阳,张培震,刘百篪,等.2004.青藏高原东北缘晚第四纪活动构造的几何图像与构造转换[J].地质学报,78(2):270-278.
张辉,高原,石玉涛,等.2012.基于地壳介质各向异性分析青藏高原东北缘构造应力特征[J].地球物理学报,55(1):95-104.
张辉.2007.青藏高原东北缘基于小震震源机制解的区域应力场特征研究[D].兰州:中国地震局兰州地震研究所.
CRAMPIN S,BOOTH D C.1985.Shear-wave polarizations near the North Anatolian Fault-II.Interpretation in terms of crack-induced anisotropy[J].Geophysical Journal International,83(1):75-92.
CRAMPIN S,PACOCK S.2005.A review of shear-wave splitting in the compliant crack-critical anisotropic Earth[J].Wave Motion,41(1):59-77.
CRAMPIN S,VOLTI T,STEFANSSON R.1999.A successfully stressforecast earthquake[J].Geophysical Journal International,138(1):1-5.
CRAMPIN S,VOLYI T,CHASTIN S,et al.2002.Indication of high pore-fluid pressures in a seismically-active fault zone[J].Geophysical Journal International,151(2):1-5.
CRAMPIN S.1981.Review of wave motion in anisotropic and cracked media[J].Wave Motion,3(4):343-391.
CRAMPIN S.1984.Effective anisotropic elastic constants for wave propagation through cracked solids[J].Geophysical Journal of the Royal Astronomical Society,76(1):135-145.
GAO Y,CRAMPIN S.2004.Observations of stress relaxation before earthquakes[J].Geophysical Journal International,157(2):578-582.
GAO Y,WANG P,ZHENG S,et al.1998.Temporal changes in shearwave splitting at an isolated swarm of small earthquakes in 1992 near Dongfang,Hainan Island,southern China[J].Geophysical Journal International,135(1):102-112.
TAPPONNIER P,ZHIQIN X,ROGER F,et al.2001.Oblique stepwise rise and growth of the Tibet plateau[J].Science,294(5547):1671-1677.
WU J,ZHANG Z,KONG F,et al.2015.Complex seismic anisotropy beneath western Tibet and its geodynamic implications[J].Earth and Planetary Science Letters,413:167-175.
XU T,WU Z,ZHANG Z,et al.2014.Crustal structure across the Kunlun fault from passive source seismic profiling in East Tibet[J].Tectonophysics,627:98-107.