CAJ | 학술논문

通过分析汶川 M 8.0地震前后山西地震带 GPS 速度场以及由此计算得到的现今构造应变率场,结果显示：(1)汶川 M 8.0地震后,山西地震带各区域的运动方向均不同程度向西偏转,太原盆地及其以北的区域由1999-2007年的 SW 或 SSW 向转为 SWW 向,且运动速率由平均约2 mm/a增加到约4 mm/a,太原盆地以南的区域由之前的 SSE 向转为 SW 向。(2)汶川 M 8.0地震后,山西地震带的应变率场显著增强,大同盆地、太原盆地北段和临汾盆地西南段形成了三个压性应变集中区,2010年在这三个区域内分别发生了大同 M 4.5、阳曲 M 4.6和河津 M 4.8地震,可能由于这种压性应变积累的区域应力场环境有利于山西地震带中强地震的孕育和发生。(3)2009-11年,受日本 M 9.0地震的影响,山西地震带向西运动的速率有所减弱,应变率场张性变化明显,太原盆地及其以北区域平均速率下降为约2~3 mm/a,太原盆地以南的区域由 SW 向转为整体向南运动的格局,有恢复到1999-2007年背景运动状态的迹象。
통과분석문천 M 8.0지진전후산서지진대 GPS 속도장이급유차계산득도적현금구조응변솔장,결과현시：(1)문천 M 8.0지진후,산서지진대각구역적운동방향균불동정도향서편전,태원분지급기이북적구역유1999-2007년적 SW 혹 SSW 향전위 SWW 향,차운동속솔유평균약2 mm/a증가도약4 mm/a,태원분지이남적구역유지전적 SSE 향전위 SW 향。(2)문천 M 8.0지진후,산서지진대적응변솔장현저증강,대동분지、태원분지북단화림분분지서남단형성료삼개압성응변집중구,2010년재저삼개구역내분별발생료대동 M 4.5、양곡 M 4.6화하진 M 4.8지진,가능유우저충압성응변적루적구역응력장배경유리우산서지진대중강지진적잉육화발생。(3)2009-11년,수일본 M 9.0지진적영향,산서지진대향서운동적속솔유소감약,응변솔장장성변화명현,태원분지급기이북구역평균속솔하강위약2~3 mm/a,태원분지이남적구역유 SW 향전위정체향남운동적격국,유회복도1999-2007년배경운동상태적적상。
We obtain the horizontal velocity field and tectonic strain rate field of the Shanxi seis-mic zone derived from Global Positioning System(GPS)data before and after the Wenchuan M 8. 0 earthquake.The results indicate that after the Wenchuan M 8.0 earthquake,the velocity of each region in the Shanxi seismic zone deflected westward in varying degrees.The north area including Taiyuan Basin shifted to SWW from SW and SSW directions in 1 999 -2007,and the velocity de-veloped from an average of approximately 2 mm/a to 4 mm/a.In addition,the area south of Taiyuan Basin shifted to SW from a SSE direction.The strain rate field in the Shanxi seismic zone was significantly enhanced after this earthquake and formed three compressive strain concentra-tion areas in Datong Basin,north Taiyuan Basin,and southwest Linfen Basin.In these respective areas,the Datong M 4.5,Yangqu M 4.6,and Hejin M 4.8 earthquakes occurred in 2010.These earthquakes may have occurred because a regional stress field environment with compressive strain accumulation is beneficial to the formation and occurrence of a moderate earthquake in the Shanxi seismic zone.Moreover,because of the Japan M 9.0 earthquake,the westward velocity of the Shanxi seismic zone was weakened,and the strain rate field expanded obviously during 2009 to 201 1.In addition,the velocity in the north area including Taiyuan Basin decreased to approximate-ly 2~3 mm/a,and the area south of Taiyuan Basin moved toward the south from the SW direc-tion.This area may return to the background velocity of that during 1 999 to 2007 in the future.