CAJ | 학술논문

基于2000年7月—2009年6月龙门山及其邻区的震源机制解资料，采用 Gephart ＆Forsyth 方法，反演得到了汶川地震前后该地区构造应力主方向的空间分布．结果显示：沿鲜水河断裂带及其北部地区，构造应力场变化显著，区域构造应力的最大主应力方位由 NNW变为 NW，断层错动类型由正断型兼走滑型变为走滑型；沿龙门山断裂带的构造应力最大主应力方向仍然为近 EW 和 NE 向，但其 EW 向范围在向 NE 方向扩张，其南部汶川地震震中附近异常带范围在收缩．另一方面，对上述时间段龙门山及其邻区不同时段构造应力场的反演结果表明，其构造应力场的特征参数（包括 R 值、应力洛德参数μ以及3个主应力的方位角和仰角等）均从第13时窗开始出现显著变化，这表明第13时窗（2006年12月—2007年1月）是一个构造应力显著变化的特征窗口．在该时窗内，地震能量积累达到一个临界状态，是汶川 MS 8．0地震发生的时间节点．
기우2000년7월—2009년6월룡문산급기린구적진원궤제해자료，채용 Gephart ＆Forsyth 방법，반연득도료문천지진전후해지구구조응력주방향적공간분포．결과현시：연선수하단렬대급기북부지구，구조응력장변화현저，구역구조응력적최대주응력방위유 NNW변위 NW，단층착동류형유정단형겸주활형변위주활형；연룡문산단렬대적구조응력최대주응력방향잉연위근 EW 화 NE 향，단기 EW 향범위재향 NE 방향확장，기남부문천지진진중부근이상대범위재수축．령일방면，대상술시간단룡문산급기린구불동시단구조응력장적반연결과표명，기구조응력장적특정삼수（포괄 R 치、응력락덕삼수μ이급3개주응력적방위각화앙각등）균종제13시창개시출현현저변화，저표명제13시창（2006년12월—2007년1월）시일개구조응력현저변화적특정창구．재해시창내，지진능량적루체도일개림계상태，시문천 MS 8．0지진발생적시간절점．
Based on the focal mechanism solutions for Longmenshan and its adja-cent regions from July 2000 to June 2009,the spatial distribution of the main direction of tectonic stress fields are retrieved in the regions before and after the Wenchuan MS 8.0 earthquake by using the Gephart & Forsyth method.The results show that the tectonic stress fields change significantly along Xianshuihe fault zone and the region to the north,and that the maximum principal stress direction of the regional tectonic stress shifts from NNW to NW,while the faul-ting changes from combined normal fault and strike-slip to strike-slip only. Significant changes can also be observed in the tectonic stress field along the Longmenshan fault zone.Although the maximum principal stress direction still approximates to the east-west and north-east,its scope is expanding towards the east-north,and the abnormal belt near the epicenter of Wenchuan earth-quake shrinks.On the other hand,the retrieval results of the tectonic stress fields in Longmenshan and its adjacent regions during different periods from July 2000 to June 2009 show that the characteristic parameters of tectonic stress fields,including the R value,Lode parameter μ,azimuths and elevation angles of three principal stresses,begin to change significantly since the thirteenth window,suggesting that the thirteenth window (December 2006 to January 2007)is a characteristic window with significant changes in the tectonic stress. In the thirteenth window,the seismic energy is accumulated to a critical state, signaling the time node for the occurrence of Wenchuan MS 8.0 earthquake.