Geodetic constraints on the mechanism of glacial earthquakes

冰川地震机制的大地测量约束

• 批准号: 0612609
• 负责人: Meredith Nettles
• 金额: --
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-15 至 2008-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0612609&HistoricalAwards=false
• 关键词: Geodetic; constraints; mechanism; glacial; earthquakes

NettlesOPP-0612609The Principal Investigators request support for research to be carried out with a pilot field experiment in summer, 2006 at Helheim Glacier, East Greenland to obtain an understanding of the mechanisms by which glacial earthquakes are generated and their relation to glaciological and climatological processes. A new class of earthquakes occurring at glaciers in Alaska, Antarctica, and Greenland was identified in 2003 by Ekstrom. Teleseismic analysis indicates that these glacial earthquakes are the result of rapid sliding of the glacial ice over the glacier bed. Little is understood about the mechanism by which glacial earthquakes occur, but recent observations indicate a relationship with the hydrological cycle at glaciers and ice sheets. The number of earthquakes that occur on Greenland is strongly seasonally modulated, with the largest number of events occurring during the late summer months. A rapid increase in the number of earthquakes at outlet glaciers across Greenland since approximately 2000 suggests a link to large-scale climate change. This research consists of two parts: 1) a field deployment of Global Positioning System (GPS) stations on Helheim Glacier to obtain direct measurements of the displacement transients associated with glacial earthquakes, the logistical costs for which will be funded separately; and 2) integrated, interdisciplinary analysis of recorded GPS, seismic, and glaciological data using state-of-the-art techniques from each field to obtain an understanding of the mechanism by which glacial earthquakes occur. Seismic analyses will provide long-wavelength estimates of the earthquake source characteristics, while the geodetic observations will provide detailed information about the timing and pattern of deformation within the glacier. A combined analysis of these datasets will result in geophysically consistent models of the deformation process, which will then be studied in the context of glaciological observations of the background glacier behavior and time-varying melting rates to evaluate the hypothesis that surface melting is linked to the generation of glacial earthquakes. Intellectual Merit. This research will lead to a greatly improved understanding of the processes controlling glacial earthquakes, a previously unknown geophysical phenomenon. It will also provide insight into modes of glacier deformation and possible connections between glacial earthquake activity and global climate change. Broader Impacts. The results will be important for glaciologists and climatologists in addition to geodesists and seismologists. The understanding of glacial earthquakes developed as a result of this study will allow remote-sensing seismic data to be used as a glaciology tool and studies of global change, while also leading to improved knowledge of the response of the solid Earth to transient deformation events at or near the surface of the Earth.

NettleSOPP-0612609主要研究人员要求对研究进行研究，以通过2006年夏季在东格陵兰岛的Helheim Glacier进行试点实验实验，以了解对冰川地震产生的机制以及它们与冰川和气候学过程的关系。埃克斯特罗姆（Ekstrom）在2003年发现了在阿拉斯加，南极洲和格陵兰岛的冰川发生的新的地震。 远距离震荡分析表明，这些冰川地震是冰川冰在冰川床上快速滑动的结果。关于冰川地震发生的机制知之甚少，但最近的观察表明与冰川和冰盖的水文循环有关系。格陵兰岛发生的地震数量受到季节性调节，其中最多的事件发生在夏末。自2000年以来，格陵兰出口冰川的地震数量迅速增加，这表明与大规模气候变化有联系。这项研究由两个部分组成：1）Helheim冰川上全球定位系统（GPS）站的现场部署，以获得与冰川地震相关的位移瞬变的直接测量，该位移是分别资金的后勤成本； 2）使用来自每个领域的最新技术对记录的GP，地震和冰川数据进行综合的，跨学科的分析，以了解发生冰川地震的机制。地震分析将提供地震源特征的长波长估计，而大地观察结果将提供有关冰川内变形的时机和模式的详细信息。对这些数据集的结合分析将导致地球物理一致的变形过程模型，然后在冰川学观察背景冰川行为和时变熔点的背景下进行研究，以评估表面融化与表面融化有关的假说产生冰川地震。智力优点。这项研究将导致对控制冰川地震的过程的理解，这是一种以前未知的地球物理现象。它还将洞悉冰川变形模式以及冰川地震活动与全球气候变化之间的可能联系。更广泛的影响。 除了地球学家和地震学家之外，该结果对冰川学家和气候学家也很重要。这项研究所发展的对冰川地震的理解将允许将遥感的地震数据用作冰川学工具和对全球变化的研究，同时也导致人们对实心土对固体对瞬态变形事件的反应的了解得到了改善。或靠近地球的表面。