Stability Assessment and Geomorphological Evolution of Sea Natural Arches by Geophysical Measurement: The Case Study of Wied Il-Mielah Window (Gozo, Malta)
Stability Assessment and Geomorphological Evolution of Sea Natural Arches by Geophysical Measurement: The Case Study of Wied Il-Mielah Window (Gozo, Malta)
复制标题
通过地球物理测量对海洋天然拱门进行稳定性评估和地貌演化：Wied Il-Mielah 窗（马耳他戈佐岛）案例研究
作者：
G. Leucci;R. Persico;L. De Giorgi;M. Lazzari;E. Colica;S. Martino;R. Iannucci;L. Galone;S. D’Amico
Wied il-Mielaħ Window（戈佐岛-马耳他）是马耳他戈佐岛西北海岸的一个石灰岩天然拱门。它位于 Wied il-Mielaħ 山谷的尽头，Għarb 村以北。这座天然拱门不像蔚蓝之窗那样出名，蔚蓝之窗于 2017 年 3 月在一场暴风雨后倒塌，但尽管如此，它也是一座雄伟而重要的天然纪念碑。过去，Wied il-Mielah 山谷负责将周边地区的废水直接通过 Wied il-Mielah 窗排放到地中海。在通往公海的拱门下方，污水旗经常清晰可见。拱门的自然特征提供了出色的旅游景点。为了避免“蔚蓝之窗”发生同样的情况，本文提出了一种结合被动地震、探地雷达（GPR）、地质/地貌调查和矿山工程方法的崩塌危险评估方法。在这项研究中，采用了基于以下方法的方法：（i）被动地震方法来研究构成窗户的岩体的物理力学特征； (ii) 探地雷达方法，以证明保存状态（即压裂强度）； (iii) 地质/地貌调查以获得裂缝模式； (iv) 按比例跨度进行实证分析，以评估拱的稳定性。采用静态方法计算的安全系数为 3.75，海洋拱门在 50 年和 100 年内崩塌的概率为 3.75。
The Wied il-Mielaħ Window (Gozo–Malta) is a limestone natural arch on the north-western coast of the island of Gozo in Malta. It is located at the end of the Wied il-Mielaħ valley north of the village of Għarb. This natural arch is less well known than the Azure Window, which collapsed in March 2017 following a heavy storm, but notwithstanding, it is an imposing and important natural monument too. In the past, the Wied il-Mielah valley was responsible for discharging wastewater from the surrounding localities to the Mediterranean directly at the Wied il-Mielah Window. The sewage flag was often clearly visible underneath the archway into the open sea. The natural features of the arch provide an outstanding touristic attraction. To avoid what happened to the Azure Window, a methodology for the evaluation of the collapse hazard, combining passive seismic, ground penetrating radar (GPR), geological/geomorphological surveys and mine engineering methods, is here proposed. In this study, a methodological approach was applied, based on the following: (i) passive seismic method to study the physical–mechanical characteristics of the rock mass that constitutes the window; (ii) GPR method in order to demonstrate the conservation state (i.e., the intensity of fracturing); (iii) geological/geomorphological surveys in order to obtain a crack pattern; and (iv) scaled span empirical analysis in order to evaluate the stability of the arch. The calculation of the safety factor, with a static method, gave a value equal to 3.75 with a probability of collapse of the marine arch within 50 and 100 years.