地球学报
地毬學報
지구학보
ACTA GEOSCIENTIA SINICA
2015年
3期
257-269
,共13页
王焕%李海兵%司家亮%孙知明%付小方%刘栋梁%裴军令%李成龙%张佳佳%宋圣荣%郭力伟%MORI James%薛莲%BRODSKY E.Emily%云锟%龚正
王煥%李海兵%司傢亮%孫知明%付小方%劉棟樑%裴軍令%李成龍%張佳佳%宋聖榮%郭力偉%MORI James%薛蓮%BRODSKY E.Emily%雲錕%龔正
왕환%리해병%사가량%손지명%부소방%류동량%배군령%리성룡%장가가%송골영%곽력위%MORI James%설련%BRODSKY E.Emily%운곤%공정
汶川地震%同震弱化%断裂愈合%摩擦系数%映秀-北川断裂带%龙门山
汶川地震%同震弱化%斷裂愈閤%摩抆繫數%映秀-北川斷裂帶%龍門山
문천지진%동진약화%단렬유합%마찰계수%영수-북천단렬대%룡문산
Wenchuan earthquake%coseismic weakening%fault healing%friction coefficient%Yingxiu-Beixhuan fault%Longmen Mountain
2008年汶川地震后，人们不得不思考问题是：大地震是如何发生的？下一次大地震什么时候发生？也就是涉及地质学家和地球物理学家一直未解决的科学问题：断层是如何破裂的？震后断裂是如何愈合的？我们试图通过对汶川地震断裂带结构、断裂摩擦行为和断裂愈合过程的研究来回答这些问题。本文将介绍通过对地表露头和汶川地震断裂科学钻探一号孔(WFSD)岩心中汶川地震主滑移带的详细研究，以及钻孔中长期温度监测来分析有关汶川地震断裂动态弱化和摩擦行为，并结合钻孔中长期水文监测计算所得断裂带渗透率变化，分析震后断裂愈合过程，进而探讨和认识汶川地震断裂作用所涉及的上述问题。经过详细研究，确定了汶川地震断裂带(映秀—北川断裂带)宽105~240 m、具有五个不同断裂岩组合的内部结构，是一条经常发生大地震、具多种弱化机制的断裂带；发现了汶川地震不仅具有同震石墨化作用，而且测量到目前世界上最低的动态摩擦系数(≤0.02)，同时首次记录到大地震后断裂快速愈合信息。这些研究结果不仅直接回答了一直困扰在地震地质和地震物理学领域几十年的关键问题，而且对完善地震断裂理论和认识汶川地震机制具有极其重要的意义，为防震减灾提供了理论依据。
2008年汶川地震後，人們不得不思攷問題是：大地震是如何髮生的？下一次大地震什麽時候髮生？也就是涉及地質學傢和地毬物理學傢一直未解決的科學問題：斷層是如何破裂的？震後斷裂是如何愈閤的？我們試圖通過對汶川地震斷裂帶結構、斷裂摩抆行為和斷裂愈閤過程的研究來迴答這些問題。本文將介紹通過對地錶露頭和汶川地震斷裂科學鑽探一號孔(WFSD)巖心中汶川地震主滑移帶的詳細研究，以及鑽孔中長期溫度鑑測來分析有關汶川地震斷裂動態弱化和摩抆行為，併結閤鑽孔中長期水文鑑測計算所得斷裂帶滲透率變化，分析震後斷裂愈閤過程，進而探討和認識汶川地震斷裂作用所涉及的上述問題。經過詳細研究，確定瞭汶川地震斷裂帶(映秀—北川斷裂帶)寬105~240 m、具有五箇不同斷裂巖組閤的內部結構，是一條經常髮生大地震、具多種弱化機製的斷裂帶；髮現瞭汶川地震不僅具有同震石墨化作用，而且測量到目前世界上最低的動態摩抆繫數(≤0.02)，同時首次記錄到大地震後斷裂快速愈閤信息。這些研究結果不僅直接迴答瞭一直睏擾在地震地質和地震物理學領域幾十年的關鍵問題，而且對完善地震斷裂理論和認識汶川地震機製具有極其重要的意義，為防震減災提供瞭理論依據。
2008년문천지진후，인문불득불사고문제시：대지진시여하발생적？하일차대지진십요시후발생？야취시섭급지질학가화지구물이학가일직미해결적과학문제：단층시여하파렬적？진후단렬시여하유합적？아문시도통과대문천지진단렬대결구、단렬마찰행위화단렬유합과정적연구래회답저사문제。본문장개소통과대지표로두화문천지진단렬과학찬탐일호공(WFSD)암심중문천지진주활이대적상세연구，이급찬공중장기온도감측래분석유관문천지진단렬동태약화화마찰행위，병결합찬공중장기수문감측계산소득단렬대삼투솔변화，분석진후단렬유합과정，진이탐토화인식문천지진단렬작용소섭급적상술문제。경과상세연구，학정료문천지진단렬대(영수—북천단렬대)관105~240 m、구유오개불동단렬암조합적내부결구，시일조경상발생대지진、구다충약화궤제적단렬대；발현료문천지진불부구유동진석묵화작용，이차측량도목전세계상최저적동태마찰계수(≤0.02)，동시수차기록도대지진후단렬쾌속유합신식。저사연구결과불부직접회답료일직곤우재지진지질화지진물이학영역궤십년적관건문제，이차대완선지진단렬이론화인식문천지진궤제구유겁기중요적의의，위방진감재제공료이론의거。
After the 2008 Wenchuan earthquake, questions as to how earthquakes occur and when the next large earthquake happens have been asked. These questions are involved in the scientific questions which have been unsolved by geologists and geophysicists, for examples, how do faults rupture? How do faults heal in preparation for the next earthquake? The authors are trying to answer these questions by investigating the internal structures of the Wenchuan earthquake fault zone, fault friction behavior and healing process. The principal slip zone of the Wenchuan earthquake was determined by detailed research based on the WFSD-1 core and outcrop investigation. The dynamic weakening and friction behavior of the Wenchuan earthquake fault was analyzed by long-term temperature monitoring. Long-term hydrological monitoring reveals permeability variations in the Wenchuan fault zone which indicate fault healing process. Based on the information obtained, this paper discusses the Wenchuan earthquake faulting process and the above questions. It is confirmed that the Wenchuan earthquake fault zone (the Yingxiu-Beichuan fault zone) was 105~240 m wide and consisted of 5 different units with different fault rocks, where seismic events occurred repeatedly with multiple coseismic fault weakening mechanisms. Coseismic graphitization occurred during the Wenchuan earthquake; the lowest dynamic friction coefficient (0.02) was measured, and for the first time, the signals showing quick fault healing were recorded. These results not only directly answer the key questions that have puzzled geologists and seismophysiccal researchers for decades but also have important significance for improving the seismic faulting theory and understanding the Wenchuan earthquake fault mechanisms, thus providing a theoretical basis for seismic prevention and disaster mitigation.
