Murray John B, van Wyk de Vries Benjamin, Pitty Andy, Sargent Phil, Wooller Luke
1School of Environment, Earth and Ecosystem Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA UK.
2Laboratoire Magmas et Volcans, Université Clermont Auvergne, Observatoire du Physique du Globe de Clermont, UMR6524-CNRS, Campus Universitaire des Cézeaux, 6 Avenue Blaise Pascal, TSA 60026 - CS 60026, 63178 Aubiere, Cédex France.
Bull Volcanol. 2018;80(4):40. doi: 10.1007/s00445-018-1209-1. Epub 2018 Mar 23.
Geological field evidence and laboratory modelling indicate that volcanoes constructed on slopes slide downhill. If this happens on an active volcano, then the movement will distort deformation data and thus potentially compromise interpretation. Our recent GPS measurements demonstrate that the entire edifice of Mt. Etna is sliding to the ESE, the overall direction of slope of its complex, rough sedimentary basement. We report methods of discriminating the sliding vector from other deformation processes and of measuring its velocity, which averaged 14 mm year during four intervals between 2001 and 2012. Though sliding of one sector of a volcano due to flank instability is widespread and well-known, this is the first time basement sliding of an entire active volcano has been directly observed. This is important because the geological record shows that such sliding volcanoes are prone to devastating sector collapse on the downslope side, and whole volcano migration should be taken into account when assessing future collapse hazard. It is also important in eruption forecasting, as the sliding vector needs to be allowed for when interpreting deformation events that take place above the sliding basement within the superstructure of the active volcano, as might occur with dyke intrusion or inflation/deflation episodes.
地质实地证据和实验室模拟表明，在斜坡上形成的火山会向山下滑动。如果这种情况发生在活火山上，那么这种运动会使形变数据失真，从而可能影响解释结果。我们最近的全球定位系统（GPS）测量结果表明，埃特纳火山的整个山体正朝着东南偏东方向滑动，这与它复杂粗糙的沉积基底的总体斜坡方向一致。我们报告了从其他形变过程中区分滑动矢量并测量其速度的方法，在2001年至2012年期间的四个时间段里，其平均速度为每年14毫米。虽然由于侧翼不稳定导致火山的一个部分发生滑动的情况很普遍且广为人知，但这是首次直接观测到整个活火山的基底滑动。这一点很重要，因为地质记录显示，这类滑动的火山在下坡一侧容易发生毁灭性的扇形崩塌，在评估未来的崩塌危险时应考虑整个火山的迁移情况。这在火山喷发预测中也很重要，因为在解释活火山上层结构中发生在滑动基底之上的形变事件（如岩脉侵入或膨胀/收缩事件）时，需要考虑滑动矢量。
