SGER: Resolving Coseismic Stress Drop, Afterslip, and Viscous Relaxation Caused by Mw=8.3, November 15, 2006 Kuril Earthquake: Evidence from GPS

西北太平洋边缘的千岛俯冲带是太平洋板块快速俯冲北美板块的高原边界。2006年11月15日千岛大地震破裂了俯冲带地震活动中最显著的空区之一；它发生在600公里长的千岛弧段，近一个世纪没有发生过一次大地震。在同一时间间隔内，北部(堪察加半岛)和南部(千岛群岛南部和北海道)发生了几次大地震。这项用于勘探研究的小额赠款提供了一个独特的机会来解决和分析最近地震后的同震应力降、余滑和粘性松弛。SGER的这项建议侧重于在2007年5月进行关键的、具有时间敏感性的观测，这将使这次地震及其后果的研究成为可能。拟议的项目解决了与这一活动有关的几个重要问题。2006年11月15日，太平洋板块俯冲到北美板块(或鄂霍次克板块)之下形成的应变中，有多少在同震和震后释放？千岛群岛中部和北部发生更多大地震并伴随着太平洋范围的海啸的危险是什么？这项研究依赖于2006年11月15日地震前几个月在千岛弧上建立的连续全球定位系统(CGPS)站，以及调查人员打算在距离地震破裂最近的岛屿上安装的新的CGPS站。为了实现该项目的目标，调查人员将使用NOAA号的巡航，该船将于2007年5月中旬从堪察加的彼得罗巴甫洛夫斯克出发，前往许多千岛群岛。广泛的影响包括与俄罗斯科学家的国际合作，可能影响地震危险的研究，以及重要数据的收集。

The Kuril subduction zone at the northwest Pacific Ocean margin is the plateboundary where the Pacific plate is rapidly underthrusting the North American plate. Great Mw=8.3November 15, 2006 Kuril earthquake ruptured one of the most conspicuous gaps in the subduction-zoneseismic activity; it occurred on the 600-km long Kuril arc segment with not a single great earthquake forabout a century. In the same time interval, the segments to the north (Kamchatka) and south (the southernKurils and Hokkaido) exhibited several great earthquakes. This Small Grant for ExploratoryResearch addresses a unique opportunity to resolve and analyze coseismic stress drop, afterslip, andviscous relaxation following this recent earthquake. This SGER proposal focuses on making in May 2007the critical time-sensitive observations that will enable the studies of this earthquake and itsconsequences. The proposed project addresses several important questions that arise in connection withthis event. How much of the strain built up from the subduction of the Pacific plate beneath the NorthAmerican plate (or the Okhotsk plate) has been released on November 15, 2006 coseismically andpostseismically? What is the danger of further great earthquakes accompanied by Pacific-wide tsunamisin the central and northern Kurils?The research relies on a combination of continuous GPS (CGPS) stations over the Kuril arc established several months before the November 15, 2006 earthquake and new CGPS stations that the investigators intend to install on the islands nearest to the rupture of the earthquake. To accomplish the goal of the project, the investigators will use a cruise of the ship of NOAA, which shall start in mid-May 2007 from Petropavlovsk, Kamchatka to many Kuril islands.Broader Impacts include international collaborations with Russian scientists, research that may impact earthquake hazards and important data collection.