四川地震
四川地震
사천지진
EARTHQUAKE RESEARCH IN SICHUAN
2011年
4期
8-12,45
,共6页
杜方%龙德雄%江在森%王庆良%牛安福%张晶%苏琴
杜方%龍德雄%江在森%王慶良%牛安福%張晶%囌琴
두방%룡덕웅%강재삼%왕경량%우안복%장정%소금
汤家坪场地%跨断层%短水准(基线)监测%形变异常
湯傢坪場地%跨斷層%短水準(基線)鑑測%形變異常
탕가평장지%과단층%단수준(기선)감측%형변이상
Tangjiaping observation site%fault-crossing measurement%monitoring of short leveling and baseline measurement%deformation monitoring
2011年以来，四川宁南汤家坪场地出现加速变化重大异常，为此中国地震局组成异常落实工作组开展现场落实，现场调查研究表明：（1）汤家坪场地观测点跨过次级断层，从破碎带中出现的石林现象，其物质组成不是第四系地层，石林陡立变形，方向性较好，与次级断裂的走向一致，应为构造岩受到挤压后变形的结果；（2）汤家坪观测场地各观测点位是稳定的。A点位于次级断层的南西盘上，从地质剖面图看出，桩基础为二迭系下统（P1）石灰岩、页岩、砂岩地层，基岩向下是有根的，整体基础是稳定的；B、C点均位于次级断层的北东盘上，沿公路边位置布置，基础部分是稳定的；（3）根据汤家坪场地1991年以来观测到的短水准、短基线曲线分析，观测结果没有明显的年变或非构造变形现象的干扰，反映了该场地跨越次级断层构造变形的实际变化，场地监测反映了次级断层的构造活动；（4）汤家坪场地A—B和A—C短基线、短水准的近期突出变化主要反映了跨越的次级断层的新活动。
2011年以來，四川寧南湯傢坪場地齣現加速變化重大異常，為此中國地震跼組成異常落實工作組開展現場落實，現場調查研究錶明：（1）湯傢坪場地觀測點跨過次級斷層，從破碎帶中齣現的石林現象，其物質組成不是第四繫地層，石林陡立變形，方嚮性較好，與次級斷裂的走嚮一緻，應為構造巖受到擠壓後變形的結果；（2）湯傢坪觀測場地各觀測點位是穩定的。A點位于次級斷層的南西盤上，從地質剖麵圖看齣，樁基礎為二迭繫下統（P1）石灰巖、頁巖、砂巖地層，基巖嚮下是有根的，整體基礎是穩定的；B、C點均位于次級斷層的北東盤上，沿公路邊位置佈置，基礎部分是穩定的；（3）根據湯傢坪場地1991年以來觀測到的短水準、短基線麯線分析，觀測結果沒有明顯的年變或非構造變形現象的榦擾，反映瞭該場地跨越次級斷層構造變形的實際變化，場地鑑測反映瞭次級斷層的構造活動；（4）湯傢坪場地A—B和A—C短基線、短水準的近期突齣變化主要反映瞭跨越的次級斷層的新活動。
2011년이래，사천저남탕가평장지출현가속변화중대이상，위차중국지진국조성이상락실공작조개전현장락실，현장조사연구표명：（1）탕가평장지관측점과과차급단층，종파쇄대중출현적석림현상，기물질조성불시제사계지층，석림두립변형，방향성교호，여차급단렬적주향일치，응위구조암수도제압후변형적결과；（2）탕가평관측장지각관측점위시은정적。A점위우차급단층적남서반상，종지질부면도간출，장기출위이질계하통（P1）석회암、혈암、사암지층，기암향하시유근적，정체기출시은정적；B、C점균위우차급단층적북동반상，연공로변위치포치，기출부분시은정적；（3）근거탕가평장지1991년이래관측도적단수준、단기선곡선분석，관측결과몰유명현적년변혹비구조변형현상적간우，반영료해장지과월차급단층구조변형적실제변화，장지감측반영료차급단층적구조활동；（4）탕가평장지A—B화A—C단기선、단수준적근기돌출변화주요반영료과월적차급단층적신활동。
The quick changes of fault slip in the fault-crossing deformation measurement of Tangjiaping site have appeared since 2011. A special term from several unites of CEA went to the field in order to investigate these abnormal changes. Our careful study shows following 4 possible conclusions ： （ 1 ） the measurement points of site are located in both sides of sub-fault in Tangjiaping. In other words, from field investigation, the measurement site crosses a sub-fault and the geological structure around the observation site are caused by the compressing stress; （2） The point A is located in south-west foolwall and has a steady basement with rock of limestone, shale and sandstone of Permian. The point B and C are located in the north-eastern side of the fault and by the side of a road and the basement of the points is stable as weE; （3） According to the analyzing the observation data of short level- ing and baseline carried out in Tangjiaping since 1991, the layout of the measurement site crosses the fault and the quick abnormal changes of measurement are caused by the activity of this sub-fault. （4） The observation data change of baseline and leveling measurement between A and B, A and C result from the tectonic activity of this sub-fault.
