RAPID Response to Tohoku Earthquake: Participation in Marine Geophysical Surveys of the Quake Rupture Zone

我们建议参加一到两次海洋地球物理调查，覆盖2011年3月日本本州岛东北大地震的破裂地带。为了应对这场大地震，日本海洋地球科学技术厅地球演化研究所开展了一项海洋地球物理调查计划，试图探测与这次地震有关的海底和地下结构--S破裂。其中一次巡航将包括在6-7月恢复和重新部署OBS期间的多波束水深测绘。一项更广泛的MCS调查计划在8月进行。再加上广泛的陆地地震仪和GPS网络，近海数据集为研究大地震期间与破裂有关的形变提供了前所未有的机会。摩尔和他的学生被邀请参加离岸调查，以帮助数据采集和船上数据处理，并参与离岸数据集的结构解释和综合。参加邮轮的主要好处是，我们还可以参与数据分析阶段。我们将能够将新的数据集与IFREE以前收集的地震反射和水深数据结合起来。将在地震破裂带收集的地震反射数据将作为现场勘测，向IODP提出在东北海域进行快速反应钻井的建议。地震数据将是确定钻探目标的关键。我们注意到，该地区较老的地震线虽然非常适合解释区域构造，但没有成像任何潜在的钻探地点，因此在任何钻探之前都需要高质量的图像。这项工作需要迅速获得资金的主要原因是，无论我们是否能够参与，日本人都将按计划进行这项工作。如果我们必须通过？标准？由于下一次提案的截止日期是8月份，因此在作出供资决定时，这项工作将已经完成。因此，我们将失去让美国科学家以相对较低的成本及早获得这一大型数据集的机会。广泛的影响该项目的一个产品将是地震反射和多波束测深数据集，这将有助于描述地球的特征-S最好地记录了大地震。虽然这个数据集将在日本境内存在，但它将在许多月(或几年)内不会向非日本研究人员发布。我们的参与将确保美国科学家能够帮助解释数据。地震反射数据将被用作现场勘测，以确定快速反应的钻井计划是否会有合适的钻井目标。该项目还将为两名研究生提供宝贵的出海经验。

We propose to participate in one or two marine geophysical surveys covering the rupture zone of the March 2011 great earthquake off Tohoku, Honshu, Japan during summer, 2011. In response to this great earthquake, the Institute For Research on Earth Evolution (IFREE) of the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) has undertaken a program of marine geophysical surveys to try to detect seafloor and subsurface structures associated with the quake?s rupture. One cruise will include multibeam bathymetric mapping during OBS recovery and redeployment in June-July. A more extensive MCS survey is planned for August. Coupled with the extensive on-land seismograph and GPS network, the offshore data set presents an unprecedented opportunity to study deformation associated with rupture during a great earthquake. Moore and his students have been invited to participate in the offshore to help with data acquisition and on-board data processing and to participate in the structural interpretation and synthesis of the offshore data sets. The main advantage of participating in the cruises is that we will also be able to participate in the data analysis phase. We will be able to combine the new data sets with seismic reflection and bathymetric data collected previously by IFREE. The seismic reflection data to be collected in the earthquake rupture zone will be used as a site survey for a proposal to IODP for Rapid Response Drilling off Tohoku. The seismic data will be essential for defining drilling targets. We note that the older seismic lines in this area, while excellent for interpreting the regional tectonics, do not image any potential drill sites, so high-quality images will be required in advance of any drilling. The main reason why this work needs to be funded quickly is because the Japanese will be carrying out the work as already scheduled, whether or not we are able to participate. If we have to go through the ?standard? proposal process, with the next proposal deadline being in August, the work will have already been completed by the time funding decisions could be made. We would thus lose out on this opportunity for U.S. scientists to have early access to this large data set at relatively low cost.Broader impactsOne product of this project will be a seismic reflection and multibeam bathymetry data set that will help characterize the Earth?s best documented great earthquake. Although this data set will exist within Japan, it will not be released to non-Japanese researchers for many months (or years). Our participation will ensure that US scientists will be able to help interpret the data. The seismic reflection data will be used as a site survey to determine whether or not a rapid-response drilling program will have suitable drill targets. This project will also provide valuable sea-going experience for two graduate students.