Active Tectonics of Diffuse Intracontinental Deformation

大陆内板块边界通常表现为广泛的扩散变形区，它表现为微板块系统还是连续体，目前尚不清楚。大盆地就是一个典型的例子。为了确定今天观测到的应变模式是否反映了微板趋势，已经建立了一个18站的GPS网络，并已运行了一年。该合同提供了额外三年的资金，以完成总共四年的网络监测。在此时间之后，速率不确定度将足以区分微孔板和连续体的行为。要解决的基本科学问题将是更好地理解大陆内板块边界。这种理解是增加我们板块构造知识的一个基本概念。此外，这些地区的地震危险性可以进一步量化。为此，重要的是要知道板内应变是否局限于地震带内，或者地震活动是否特别地跨越一个相对均匀应变积累的宽区域。为了解决这个问题，首席研究员正在使用一系列GPS站点来计算以毫米/年为单位的年位移及其分布。由此，可以计算应力和应变，并检查应力场来回答这些问题。＊＊＊

9725766 Wernicke It is unclear if intracontinental plate boundaries, usually expressed as wide zones of diffuse deformation, behave as a system of microplates, or as a continuum. The Great Basin is a prime example of an area that behaves in this way. To determine if the observed strain pattern of today reflects a microplate trend, an 18 station GPS network has been established and has been operating for one year. This award provides an additional three years of funding to complete a total of four years of monitoring the network. After such time, the rate uncertainties will be sufficient to distinguish between microplate and continuum behavior. The basic scientific question to be solved will be a better understanding of intracontinental plate boundaries. This understanding is a fundamental concept to add to our knowledge of plate tectonics. In addition, the seismic hazard of such areas may be further quantified. To such an end, it is important to know if intraplate strain is localized within seismic belts, or if seismicity migrates secularly across a wide zone of relatively uniform strain accumulation. To solve this question, the Principal Investigator is using a series of GPS stations to compute yearly displacement in mm/yr and its distribution. From this, stress and strain can be calculated and the stress field examined to answer these questions. ***