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

太平洋西北边缘的千岛俯冲带是太平洋板块快速向北美板块俯冲的板块边界。2006年11月15日千岛群岛发生的MW= 8.3的大地震，破坏了俯冲带地震活动中最显著的空白之一，它发生在长达600 km的千岛群岛弧段上，近世纪来没有发生过一次大地震。在同一时间段内，北部（堪察加半岛）和南部（南千岛群岛和北海道）的部分出现了几次大地震。这个探索性研究的小补助金提供了一个独特的机会来解决和分析同震应力下降，后滑，以及最近地震后的粘性松弛。本SGER建议的重点是在2007年5月进行关键的时间敏感的观测，这将使这次地震及其后果的研究。拟议的项目解决了与这一事件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）之下所产生的应变有多少在同震和震后释放？在千岛群岛中部和北方发生进一步的大地震并伴随着太平洋范围的海啸的危险是什么？该研究依赖于2006年11月15日地震前几个月建立的千岛群岛弧上的连续GPS（CGPS）站和调查人员打算在距离地震破裂最近的岛屿上安装的新CGPS站的组合。为了实现该项目的目标，调查人员将使用NOAA的船进行巡航，该船将于2007年5月中旬从堪察加半岛的彼得罗巴甫洛夫斯克出发，前往许多千岛群岛。更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和重要数据收集。

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.