Nadeau Robert M, Guilhem Aurélie
Berkeley Seismological Laboratory, University of California, Berkeley, CA 94720, USA.
Science. 2009 Jul 10;325(5937):191-3. doi: 10.1126/science.1174155.
Nonvolcanic tremors occur adjacent to locked faults and may be closely related to the generation of earthquakes. Monitoring of the San Andreas Fault in the Parkfield, California, region revealed that after two strong earthquakes, tremor activity increased in a nearly dormant tremor zone, increased and became periodic in a previously active zone, and has remained elevated and periodic for over 4 years. Static shear- and Coulomb-stress increases of 6 to 14 kilopascals from these two earthquakes are coincident with sudden increases in tremor rates. The persistent changes in tremor suggest that stress is now accumulating more rapidly beneath this part of the San Andreas Fault, which ruptured in the moment magnitude 7.8 Ft. Tejon earthquake of 1857.
非火山性震颤发生在闭锁断层附近，可能与地震的产生密切相关。对加利福尼亚州帕克菲尔德地区圣安德烈亚斯断层的监测显示，在两次强烈地震之后，震颤活动在一个几乎休眠的震颤带增加，在一个先前活跃的区域增加并变得周期性，并且已经持续升高和周期性超过4年。这两次地震产生的6至14千帕的静态剪应力和库仑应力增加与震颤速率的突然增加同时发生。震颤的持续变化表明，现在圣安德烈亚斯断层这一部分下方的应力积累得更快，该断层在1857年矩震级为7.8的特洪堡地震中发生了破裂。
