UCL Hazard Centre, Department of Earth Sciences, UCL, Gower Street, London WC1E 6BT, UK.
INGV-Osservatorio Vesuviano, Via Diocleziano 328, Napoli 80124, Italy.
Nat Commun. 2017 May 15;8:15312. doi: 10.1038/ncomms15312.
Unrest at large calderas rarely ends in eruption, encouraging vulnerable communities to perceive emergency warnings of volcanic activity as false alarms. A classic example is the Campi Flegrei caldera in southern Italy, where three episodes of major uplift since 1950 have raised its central district by about 3 m without an eruption. Individual episodes have conventionally been treated as independent events, so that only data from an ongoing episode are considered pertinent to evaluating eruptive potential. An implicit assumption is that the crust relaxes accumulated stress after each episode. Here we apply a new model of elastic-brittle failure to test the alternative view that successive episodes promote a long-term accumulation of stress in the crust. The results provide the first quantitative evidence that Campi Flegrei is evolving towards conditions more favourable to eruption and identify field tests for predictions on how the caldera will behave during future unrest.
大型破火山口的不稳定活动很少会导致喷发，这使得脆弱的社区更容易将火山活动的紧急预警视为虚假警报。一个典型的例子是意大利南部的坎皮弗莱格雷（Campi Flegrei）火山口，自 1950 年以来，那里发生了三次大规模抬升事件，导致其中心区上升了约 3 米，但没有喷发。传统上，各个事件都被视为独立的事件，因此只有正在进行的事件的数据被认为与评估喷发潜力有关。一个隐含的假设是，地壳在每次事件后都会释放积累的应力。在这里，我们应用一种新的弹脆性失效模型来检验另一种观点，即连续的事件会促进地壳中长期的应力积累。研究结果首次提供了定量证据，表明坎皮弗莱格雷正在向更有利于喷发的条件发展，并确定了对该火山口在未来不稳定期间行为的预测进行现场测试的方法。
