Seismicity, Structure and Dynamics of the Gorda Deformation Zone

板块构造的概念是，地球表面由在大洋中脊形成的大型板块组成，并在俯冲过程中被消耗，主要在洋盆边缘附近。板块构造模型解释了许多可观察到的现象，包括大地震和剧烈火山喷发的分布。板块构造理论的一个核心假设是板块是刚性的。这一假设适用于地球的大部分地区？S表面，但也有例外。一个特殊的地区是戈尔达盆地，它位于加利福尼亚州北部和俄勒冈州南部的西部。有令人信服的证据表明，该地区的海底正在积极变形？包括多次地震的发生？但几十年来，海底到底是如何变形的，为什么会变形，一直没有得到明确的解释。部署海底地震仪(OBS)的目的是提供戈尔达盆地地震活动的更详细图像，从而解决变形的庄园和原因。人们对这个问题更加感兴趣，因为戈尔达盆地正被活跃地俯冲到邻近的大陆之下，那里是主要的？巨型逆冲？众所周知，已经发生了地震。加尔达盆地的变形如何影响该地区发生大规模破坏性地震的可能性尚不清楚，但引起了相当大的社会关注。该项目的另一个更广泛的影响是，为该项目部署OBSS将补充卡斯卡迪亚倡议，即两栖部署OBSS近海和陆上地震台站。卡斯卡迪亚倡议的一个主要目的是更好地了解卡斯卡迪亚边缘的地震活动和大地震风险，该边缘从加利福尼亚州北部延伸到不列颠哥伦比亚省南部。

Plate Tectonics is the notion that the Earth?s surface is comprised of large plates that form at mid-ocean ridges and are consumed by the process of subduction, largely near the margins of ocean basins. The plate tectonic model explains many observable phenomena, including the distribution of great earthquakes and violent volcanic eruptions. A central assumption of plate tectonic theory is that the plates are rigid. This assumption applies to most of the Earth?s surface, but there are exceptions. One exceptional region is the Gorda Basin, which is located west of northern California and southern Oregon. There is compelling evidence that the seafloor in this region is actively deforming ? including the occurrence of numerous earthquakes ? but just how the seafloor is deforming and why has eluded unambiguous interpretation for several decades. This deployment of Ocean Bottom Seismographs (OBS) has the objective of yielding a more detailed picture of earthquake seismicity in the Gorda Basin, and thereby resolving the manor and cause of the deformation. There is added interest in this problem because the Gorda Basin is being actively subducted beneath the adjacent continent, where major ?megathrust? earthquakes are known to have occurred. How deformation of the Garda Basin affects the potential for large damaging earthquakes in this region is unknown, but of considerable societal interest. An added broader impact of this project is that the deployment of OBSs for this project will supplement the Cascadia Initiative, an amphibious deployment of OBSs offshore and seismic stations onshore. A principal aim of the Cascadia Initiative is to develop a better understanding of seismicity and of megathrust earthquake risk along the Cascadia margin, which extends from northern California to southern British Columbia.