地震工程学报
地震工程學報
지진공정학보
China Earthquake Engineering Journal
2014年
2期
292-300
,共9页
高好林%丁晓光%赵韬%苏利娜%古云鹤%关昕%张永奇
高好林%丁曉光%趙韜%囌利娜%古雲鶴%關昕%張永奇
고호림%정효광%조도%소리나%고운학%관흔%장영기
渭河盆地%地形变%GPS 应变场%重力场变化%布格重力异常%跨断层形变
渭河盆地%地形變%GPS 應變場%重力場變化%佈格重力異常%跨斷層形變
위하분지%지형변%GPS 응변장%중력장변화%포격중력이상%과단층형변
Weihe basin%crustal deformation%GPS strain field%changes of the gravitational field%Bouguer gravity anomaly%cros-fault deformation
在对渭河盆地 GPS 观测资料、流动重力和跨断层形变观测资料精细处理的基础上绘制了相应的时空变化图件,并对其进行了综合分析。结果表明:①陇县-岐山-周至-户县一线既是面应变压缩区,又是重力变化梯度带,还是布格重力异常梯度带,说明这一区域应力场异常变化与深部构造有关。②穿越该区域的陇县-岐山-马召断裂2010年以来断层活动表现为挤压变形特征,逆继承性构造运动显著。③在面应变率压缩区,地壳介质密度增加,重力场呈正向变化,断裂活动表现为挤压变形特征;反之则相反。④岐山-马召断裂2004年7月以后的两次逆继承性构造运动可能是甘肃迭部4.9和岷县6.6地震孕育发生过程中的远场效应。
在對渭河盆地 GPS 觀測資料、流動重力和跨斷層形變觀測資料精細處理的基礎上繪製瞭相應的時空變化圖件,併對其進行瞭綜閤分析。結果錶明:①隴縣-岐山-週至-戶縣一線既是麵應變壓縮區,又是重力變化梯度帶,還是佈格重力異常梯度帶,說明這一區域應力場異常變化與深部構造有關。②穿越該區域的隴縣-岐山-馬召斷裂2010年以來斷層活動錶現為擠壓變形特徵,逆繼承性構造運動顯著。③在麵應變率壓縮區,地殼介質密度增加,重力場呈正嚮變化,斷裂活動錶現為擠壓變形特徵;反之則相反。④岐山-馬召斷裂2004年7月以後的兩次逆繼承性構造運動可能是甘肅迭部4.9和岷縣6.6地震孕育髮生過程中的遠場效應。
재대위하분지 GPS 관측자료、류동중력화과단층형변관측자료정세처리적기출상회제료상응적시공변화도건,병대기진행료종합분석。결과표명:①롱현-기산-주지-호현일선기시면응변압축구,우시중력변화제도대,환시포격중력이상제도대,설명저일구역응력장이상변화여심부구조유관。②천월해구역적롱현-기산-마소단렬2010년이래단층활동표현위제압변형특정,역계승성구조운동현저。③재면응변솔압축구,지각개질밀도증가,중력장정정향변화,단렬활동표현위제압변형특정;반지칙상반。④기산-마소단렬2004년7월이후적량차역계승성구조운동가능시감숙질부4.9화민현6.6지진잉육발생과정중적원장효응。
We selected the gps data since we have the GPS mobile observation network in Shaanxi province,and compared with the mobile gravity and cross-fault deformation observation data,we are aimed to investigate the variation of Weihe basin topography changes and their relationships. <br> With the data of GPS mobile observation network in Shaanxi province during 2001-2010 and 2001-2012,the high-precision horizontal velocity field of Weihe basin processed by the software of GAMIT / GLOBK was obtained.The regional background strain characteristic parameters were calculated according to the velocity and strain theory by least squares collocation method. <br> We have used the software,which is updated by China Institute of Seismology,to process the mobile gravity data of Guanzhong area,we also use some points nearby Weinan to do adjustment calculation to be stable. <br> We have used the cross-fault deformation observation data,which is observed by high preci-sion balance level NI002,to do the feet long correction. <br> Based on fine processing on GPS observation data,mobile gravity and cross-fault deforma-tion observation data in Weihe basin,temporal and spatial variation maps are drawn correspond-ingly and further analyzed comprehensively combined with related deep detecting data and other research results.Results are shown mainly in 5 aspects as follows:① Longxian - Qishan -Zhouzhi- Huxian area is a surface strain compressed zone,a gravity change gradient belt and a Bouguer gravity anomaly gradient belt,which indicates that the abnormal changes in stress field in the area is related to the deep tectonics.The Moho mutants to uplift over the Erdos block and the high-speed substances in the upper mantle intrude into the lower crust is one of the deep tec-tonic backgrounds of moderate and strong earthquakes in the region.② Longxian- Qishan-Mazhao fault,passing through the above mentioned area,is of significant inverse tectonic move-ment with fault movement characterized in extrusion deformation since 2010.What should been paid more attention to is that the decrease amplitude of Dayuan 2 - 3,2010.7 ~ 2012.3 (a test point)over the fault is as high as 15.19 mm.③ In the surface strain compressed area,the crustal medium density increases and the change of gravity is positive,fault activity is of extrusion de-formation characteristics.Whereas,in the surface strain stretched area,all of the former men-tioned items are of the opposite situations.④ Two reverse tectonic movements occurred in Qis-han-Mazhao fault since July 2004 are probably the far-field effect in the pregnancy and occur-rence process of Diebu M4.9 and Minxian M6.6 earthquakes in Gansu Province.Having been ob-served for more than 20 years,related measuring sections of the Dayuan deformation site display significant reverse tectonic movement characteristics once a relatively big earthquake activity hap-pens.⑤ GPS surface strain rate,gravity field variation and cross fault deformation are greatly u-niform and correlated in ground deformation changes in western Weihe basin,which is rare and valuable geographic phenomena that may inspire and promote geoscience research in a certain de-gree.