Post-diking Response to the Sept-Oct. 2005 Boina Event, Afar Depression, Ethiopia

对九月至十月堤防后的反应。

• 批准号: 0613651
• 负责人: Eric Calais
• 金额: --
• 依托单位: Purdue 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: 2006-06-01 至 2007-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0613651&HistoricalAwards=false
• 关键词: Post; diking; Response; Sept; Oct.

The northern Afar depression is a piece of recent ocean floor with morphological characteristics similar to those observed at slow-spreading mid-oceanic ridges. We know that the separation between tectonic plates at mid-oceanic ridges is mostly accounted by episodic intrusions of vertical sheets of magma, or dikes.The processes that govern their emplacement is however poorly understood since most oceanic spreading centers lie under 2-3 thousand meters of water, making direct observations extremely difficult and expensive. Between September 14 and November 5 2005, a massive rifting event took place in Afar, with the emplacement of a 60 km long dike with up to 8 m of opening. It is the largest single rifting event known to have occurred on land since the Laki (Iceland) eruption in 1783, and the first to occur in the era of satellite geodesy. This project will use continuous GPS observations of surface motions followingthe diking event to better understand the mechanics that governs the formation of oceanic floor. Our results will also serve to assess the hazard associated with the Gabho rift and provide the local authorities with scientific data needed to make decisions on population relocation.

北方阿法尔低气压区是一块近代洋底，其形态特征与在缓慢扩张的洋中脊观察到的特征相似。我们知道，大洋中脊的构造板块之间的分离主要是由垂直岩浆岩片或岩脉的幕式侵入造成的，然而，由于大多数海洋扩张中心位于2-3千米的水下，因此对其就位的控制过程知之甚少，这使得直接观测极其困难和昂贵。 2005年9月14日至11月5日期间，阿法尔发生了一次大规模的裂谷活动，一条60公里长的堤坝就位，开口长达8米。这是自1783年拉基（冰岛）火山爆发以来，已知发生在陆地上的最大的单一裂谷事件，也是卫星大地测量时代发生的第一次。该项目将使用GPS对筑堤事件后的表面运动进行连续观测，以更好地了解海底形成的力学机制。 我们的研究结果还将有助于评估与Gabho裂谷相关的危害，并为地方当局提供做出人口迁移决策所需的科学数据。