Extreme erosion by submarine slides
Extreme erosion by submarine slides
复制标题
海底滑坡的严重侵蚀
作者：
Nugraha H
海底滑坡（包括滑坡、滑塌和泥石流）通过引发海啸和破坏重要的海底基础设施构成重大地质灾害。载玻片体积是危险评估中的一个关键参数，可通过基质和/或水夹带而显著增加。然而，滑坡的侵蚀潜力是不确定的。我们通过确定沉积（Vd）与初始排空（Ve）沉积物体积的比率来量化滑坡侵蚀力;即，通过侵蚀增加体积的滑动具有Vd/Veratio >1。我们应用这种方法的戈尔工幻灯片，一个大的（500立方公里），地震成像幻灯片澳大利亚西北部近海，并reviewedVd/Veratios为全球其他11个大型幻灯片。11个载玻片中有9个Vd/Ve> 1（中值= 2），表明初始失效后的就位体积增加。Gorgon幻灯片是最侵蚀幻灯片目前记录（Vd/Ve= 13），可能反映其通过一个高度可侵蚀的碳酸盐软泥基板。我们的新方法来量化侵蚀是重要的危险评估，因为基板流的相互作用控制滑动速度和跳动距离。滑坡体积的变化对海底基础设施影响评估也有重要影响，包括更可靠的海啸建模。
Submarine slides (including slides, slumps, and debris flows) pose major geohazards by triggering tsunami and damaging essential submarine infrastructure. Slide volume, a key parameter in hazard assessments, can increase markedly through substrate and/or water entrainment. However, the erosive potential of slides is uncertain. We quantified slide erosivity by determining the ratio of deposited (Vd) to initially evacuated (Ve) sediment volumes; i.e., slides that gain volume through erosion have aVd/Veratio >1. We applied this method to the Gorgon slide, a large (500 km3), seismically imaged slide offshore northwestern Australia, and reviewedVd/Veratios for 11 other large slides worldwide. Nine of the 11 slides haveVd/Ve> 1 (median value = 2), showing emplaced volumes increased after initial failure. The Gorgon slide is the most erosive slide currently documented (Vd/Ve= 13), possibly reflecting its passage across a highly erodible carbonate ooze substrate. Our new approach to quantifying erosion is important for hazard assessments given substrate-flow interactions control slide speed and runout distance. The variations in slide volume also have important implications for submarine infrastructure impact assessments, including more robust tsunami modeling.