地质通报
地質通報
지질통보
GEOLOGICAL BULLETIN OF CHINA
2015年
1期
58-70
,共13页
刘艳辉%赵根模%吴中海%蒋瑶
劉豔輝%趙根模%吳中海%蔣瑤
류염휘%조근모%오중해%장요
青藏高原东南缘%b值特征%地震危险性
青藏高原東南緣%b值特徵%地震危險性
청장고원동남연%b치특정%지진위험성
southeastern margin of the Tibetan Plateau%characteristic of b-value%seismic risk
基于青藏高原东南缘空间数据库及系统建立成果的基础上，综合整理青藏高原东南缘地区的1980—2013年地震信息、地震地质资料及国家基础地理信息，通过Arcgis软件及其脚本编写应用，利用空间模型初步实现了区域内1980—2013年地震活动信息的地统计分析。依据区域地震b值与地壳内部应力分布状态的负相关原理，利用b值进行大面积空间与时间扫描方法对青藏高原东南缘当前应力分布特点进行研究。以2°×2°为单元网格将研究区分为若干区，分别对其进行分时间、分单元b值计算，针对重点低b值区形成时空曲线总结大地震发生前b值曲线的时空规律，并结合之前划出的地震围空区对本区地震危险性进行综合性的中长期预测，结果表明：①汶川地震、芦山地震验证大震发生前后b值时间曲线会有水平—负增长—正增长—负增长—水平的曲线变化；②地震震级越大b值负增长的低值危险区形成时间越早，持续时间越久；③汶川大地震前川北出现大面积低b值异常区；④目前b值低值区持续时间较长的区域有：东喜马拉雅构造结、玉树—甘孜断裂、安宁河断裂—则木河断裂—鲜水河断裂—小江断裂和畹町断裂—南汀河断裂，澜沧断裂—景洪断裂与地震空区危险性预测有较多重叠。
基于青藏高原東南緣空間數據庫及繫統建立成果的基礎上，綜閤整理青藏高原東南緣地區的1980—2013年地震信息、地震地質資料及國傢基礎地理信息，通過Arcgis軟件及其腳本編寫應用，利用空間模型初步實現瞭區域內1980—2013年地震活動信息的地統計分析。依據區域地震b值與地殼內部應力分佈狀態的負相關原理，利用b值進行大麵積空間與時間掃描方法對青藏高原東南緣噹前應力分佈特點進行研究。以2°×2°為單元網格將研究區分為若榦區，分彆對其進行分時間、分單元b值計算，針對重點低b值區形成時空麯線總結大地震髮生前b值麯線的時空規律，併結閤之前劃齣的地震圍空區對本區地震危險性進行綜閤性的中長期預測，結果錶明：①汶川地震、蘆山地震驗證大震髮生前後b值時間麯線會有水平—負增長—正增長—負增長—水平的麯線變化；②地震震級越大b值負增長的低值危險區形成時間越早，持續時間越久；③汶川大地震前川北齣現大麵積低b值異常區；④目前b值低值區持續時間較長的區域有：東喜馬拉雅構造結、玉樹—甘孜斷裂、安寧河斷裂—則木河斷裂—鮮水河斷裂—小江斷裂和畹町斷裂—南汀河斷裂，瀾滄斷裂—景洪斷裂與地震空區危險性預測有較多重疊。
기우청장고원동남연공간수거고급계통건립성과적기출상，종합정리청장고원동남연지구적1980—2013년지진신식、지진지질자료급국가기출지리신식，통과Arcgis연건급기각본편사응용，이용공간모형초보실현료구역내1980—2013년지진활동신식적지통계분석。의거구역지진b치여지각내부응력분포상태적부상관원리，이용b치진행대면적공간여시간소묘방법대청장고원동남연당전응력분포특점진행연구。이2°×2°위단원망격장연구구분위약간구，분별대기진행분시간、분단원b치계산，침대중점저b치구형성시공곡선총결대지진발생전b치곡선적시공규률，병결합지전화출적지진위공구대본구지진위험성진행종합성적중장기예측，결과표명：①문천지진、호산지진험증대진발생전후b치시간곡선회유수평—부증장—정증장—부증장—수평적곡선변화；②지진진급월대b치부증장적저치위험구형성시간월조，지속시간월구；③문천대지진전천북출현대면적저b치이상구；④목전b치저치구지속시간교장적구역유：동희마랍아구조결、옥수—감자단렬、안저하단렬—칙목하단렬—선수하단렬—소강단렬화원정단렬—남정하단렬，란창단렬—경홍단렬여지진공구위험성예측유교다중첩。
Based on the establishment of the spatial databases and its system for the southeastern active tectonic zone of the Tibetan Plateau, the authors gathered earthquake information of this region from 1980 to 2013 and geohazards as well as national fundamental geographic information. Using the script writing and spatial model, the authors made a statistic analysis of the seismic activity informa?tion in this region from 1980 to 2013. Based on the principle of negative correlation between regional seismic b-value and crust inter?nal stress distribution, the authors employed a large-area temporal-spatial scanning method based on b-value to detect current stress state of the southeastern margin of the Tibetan Plateau and, in combination with the study of active structure, to provide a clue to seismic hazard discussion. Considering the spatial difference of the seismic statistical samples, the authors divided the study area into several districts of 2°×2° grid cells, and then calculated the b-value for every unit and every year. The study focused on low b-value areas, summarized b-value temporal-spatial regularity and curves and, in combination with the former study of seismic gap, made a comprehensive mid-long-term seismic hazard prediction. Some conclusions have been reached:①Wenchuan earthquake and Lushan earthquake demonstrate that before and after the marcoquake the b-value time curve will change in order of horizontal-neg?ative growth-positive growth-negative growth-horizontal; ② the greater the earthquake magnitude, the earlier the formation of the low value dangerous area of the b-value negative growth and the longer the duration; ③before Wenchuan earthquake, a large area of low b-value anomaly appeared in northern Sichuan; ④ at present, the low b-value areas that have lasted for quite a long time include eastern Himalayan syntaxis, Yushu-Garze fault, Anninghe fault-Zemuhe fault-Xianshuihe-fault-Xiaojing fault and Wanting fault-Nantinghe fault, and there exists quite a lot of overlapping between Lancang fault-Jinghong fault and the predicted seismic open risk area.
