Emplacement process and timing of large volcanic debris avalanches, Montserrat, Lesser Antilles: implications for volcanic and tsunami hazards

小安的列斯群岛蒙特塞拉特岛大型火山碎片雪崩的就位过程和时间：对火山和海啸灾害的影响

• 批准号: NE/G007667/1
• 负责人: Timothy Minshull
• 金额: $ 4.54万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2010
• 资助国家: 英国
• 起止时间: 2010 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FG007667%2F1
• 关键词: Emplacement; process; timing; large; volcanic

IODP proposal 681 was submitted to drill ten sites around the volcanic islands of Montserrat, Dominica and Martinique in the Lesser Antilles. Six sites will target recent (< 250 ka) debris avalanches generated by large scale volcanic flank collapse. Four sites located beyond the debris avalanche deposits will recover turbidites generated by the debris avalanches, and a longer term (2-10 Ma) record of volcanic eruptions and magmatic evolution. IODP 681 would be a scientific first, as it would provide the first cores to penetrate submarine debris avalanche deposits resulting from volcanic flank collapse. These collapses are some of the largest-volume (1 to 1,000 km3) mass flows on Earth. Even smaller (1 to 10 km3) flank collapse events, such as those that we will study, transport a similar amount of sediment to that delivered annually by rivers to the ocean. Recent mapping around volcanic islands suggests that flank collapses are more frequent than previously thought, especially collapses on the scale that we will study. Collapse events therefore have important implications for volcanic and tsunami hazards worldwide. In particular, the magnitude of tsunami generated by volcanic flank collapse is highly controversial. Tsunami magnitude is strongly dependent on how debris avalanches are emplaced. A better understanding of avalanche emplacement is key for predicting tsunami magnitude more accurately. Dating debris avalanche deposits in these IODP drill cores will help to understand the timing of large-scale volcanic flank collapse, and the factors that trigger such collapse. We will determine whether collapse events are typically associated with volcanic eruptions, or with periods of rapid sea level change. IODP 681 cores will help to understand how debris avalanches can be emplaced, for instance by documenting the number and composition (and hence origin) of deposit sub-units. Drill cores will also document the long term (2-10 Ma) eruptive history of these volcanoes in unusual detail. This eruptive history will guide prognosis of future volcanic activity both in the Lesser Antilles, and help to understand cycles of volcanic island construction and destruction in other locations worldwide. Are there patterns in eruption style, and are these patterns influenced by the timing of flank collapse? What conditions precede particularly large explosive eruptions? Finally, IODP 681 will document long term magmatic evolution in order to understand how igneous processes (such as partial melting, magma differentiation and transport) generate arc crust. How is magmatic evolution related to eruptive history, and timing and scale of flank collapse? Swath bathymetry, backscatter and shallow cores are available for all ten sites in IODP 681, but we lack seismic data for two Montserrat sites and one Martinique site. The UKIODP site survey would provide the seismic data for the two sites around Montserrat, whilst a French GWADASEIS cruise would provide the seismic data offshore Martinique. The UKIODP site survey would itself result in a scientific first, by collecting the first 3-d seismic data for a volcanic debris avalanche. Although seismic surveys in other locations (e.g. Canary or Hawaiian Islands) have consistently failed to penetrate and image volcanic debris avalanche deposits, previous 2-d seismic surveys around Montserrat, Dominica and Martinique have shown that these particular deposits can be imaged successfully due to relatively shallow water depths and thin character. Combining the first 3-d seismic data from this site survey, and the first drill cores for debris avalanches from IODP 681, will provide powerful new insights into their timing, triggers and emplacement process. The uniquely high resolution seismic data acquired by this site survey will provide a key reason for IODP to fund Proposal 681, as these would then be the only debris avalanche deposits worldwide to have high resolution seismic surveys.

IODP提案681被提交在蒙特塞拉特，多米尼加和马提尼克岛的火山群岛周围的十个地点。六个地点将针对大规模火山侧面塌陷产生的近期（<250 ka）碎片雪崩。位于碎片雪崩沉积物以外的四个地点将回收由碎片雪崩产生的浊度，以及长期（2-10 mA）火山喷发和岩浆演化的记录。 IODP 681将是科学的，因为它将提供第一批穿透火山侧面塌陷导致的海底杂物雪崩沉积物的核心。这些倒塌是地球上最大的数量（1至1,000 km3）的质量流。甚至较小（1至10 km3）的侧面塌陷事件，例如我们将研究的事件，将类似的沉积物运送到每年由河流传递到海洋的沉积物。最近在火山岛周围的地图表明，侧面崩溃比以前想象的要频繁，尤其是我们将研究的规模崩溃。因此，崩溃事件对全球火山和海啸危害具有重要意义。特别是，火山侧面塌陷产生的海啸的大小是高度争议的。海啸大小在很大程度上取决于碎片雪崩的安置方式。更好地理解雪崩式化是更准确地预测海啸幅度的关键。这些IODP钻芯中的约会碎片雪崩沉积物将有助于了解大型火山侧面塌陷的时机，以及引发这种崩溃的因素。我们将确定崩溃事件是否通常与火山喷发有关，还是与海平面快速变化的时期有关。 IODP 681核心将有助于了解如何通过记录存款子单元的数量和组成（因此起源）来安装碎片雪崩。钻芯还将记录这些火山的长期（2-10 MA）爆发历史，并具有不同寻常的细节。这种爆发的历史将指导未来的火山群体中对未来火山活动的预后，并有助于了解全球其他地方的火山岛建筑和破坏的周期。是否有喷发风格的模式，这些模式是否受侧面崩溃的时间影响？哪些条件在尤其是大型爆炸性喷发之前？最后，IODP 681将记录长期岩浆演化，以了解火成点过程（例如部分熔化，岩浆分化和运输）如何产生弧形壳。岩浆进化与喷发历史以及侧面塌陷的时机和规模如何相关？ IODP 681的所有十个地点都可以使用浅水测深，反向散射和浅核，但是我们缺少两个蒙特塞拉特站点和一个马提尼克派地点的地震数据。 UKIODP站点的调查将为蒙特塞拉特附近的两个地点提供地震数据，而法国gwadaseis巡航则将提供地震数据海上马提尼克岛。 UKIODP现场调查本身将首先通过收集火山碎片雪崩的第一个3D地震数据来产生科学。尽管在其他位置（例如金丝雀或夏威夷群岛）的地震调查一直未能穿透和图像火山碎屑雪崩沉积物，但蒙特塞拉特（Montserrat），多米尼卡（Dominica）和马提尼克（Martinique）围绕蒙特塞拉特（Montserrat）和马提尼克（Martinique）的先前的2-D地震调查表明，这些特定的沉积物可以由于相对较浅的水深度和薄特征而成功地产生。结合了本网站调查的第一个3D地震数据，以及IODP 681碎片雪崩的第一个钻头核心，将为他们的时机，触发器和增强过程提供强大的新见解。本网站调查获得的独特高分辨率地震数据将为IODP提供资金681的主要原因，因为这将是全球唯一进行高分辨率地震调查的杂物雪崩矿床。

项目成果

Insights into the emplacement dynamics of volcanic landslides from high-resolution 3D seismic data acquired offshore Montserrat, Lesser Antilles

• DOI: 10.1016/j.margeo.2012.10.004
• 发表时间: 2013
• 期刊: Marine Geology
• 影响因子: 2.9
• 作者: G. Crutchley;J. Karstens;C. Berndt;P. Talling;S. Watt;M. Vardy;V. Hühnerbach;M. Urlaub;S. Sarkar;D. Klaeschen;M. Paulatto;A. Friant;E. Lebas;F. Maeno