以新马德里地震带(以下简称NMSZ,图1)而知名的美国大陆中部地区,尽管远离板块边界,但却频繁发生特大地震,其发震机制一直是个未解之谜。NMSZ地区并没有大多数活动形变地区构造运动特征的显著地形起伏,但当面对该整个地区地震危险性在某些概率水平上可以与旧金山湾地区相比的证据时,我们多数人感到需要“拧自己一下以看看我们是否在做梦”。尽管在很多方面,评估NMSZ地区的危险性比评价美国西部地区更具挑战性,不确定性更大,但经过细致地科学研究,已经在地震危险性评估的最关键问题上达成了共识。 [这里给出的一致性看法反映了美国地质调查局和美国中部地震中心(一个由国家科学基金会资助的大学协会组织)2000年1月主办的一次讨论会上与会的二十几位科学家在会上及会后在国际互联网和专业会议上公开发表的一些看法。] The central continental United States, well known for the New Madrid Seismic Belt (hereinafter referred to as the NMSZ, Figure 1), has experienced frequent earthquakes despite its distance from plate boundaries and its mechanism of earthquake has been a mystery. The NMSZ does not have significant relief from tectonic movement in most deformable areas, but most face the need for evidence that the seismic risk across the entire area may be comparable to the San Francisco Bay area at some level of probability. “ Twist yourself to see if we are dreaming. ” Although in many ways the assessment of the NMSZ region is more challenging and uncertain than the assessment of the western United States, careful scientific research has reached consensus on the most critical issues in seismic hazard assessment. [The consensus presented here reflects the comparison of two dozen scientists attending a seminar held in January 2000 between the United States Geological Survey and the Central American Earthquake Center (a university association funded by the National Science Foundation) Some opinions expressed publicly at international and professional conferences during and after conferences. ]