Dipartimento di Chimica e Biologia, Università di Salerno, Fisciano, SA, Italy.
Dipartimento di Fisica, Università di Salerno, Fisciano, SA, Italy.
Sci Rep. 2017 Aug 11;7(1):7948. doi: 10.1038/s41598-017-08638-y.
Many calderas show repeated unrest over centuries. Though probably induced by magma, this unique behaviour is not understood and its dynamics remains elusive. To better understand these restless calderas, we interpret deformation data and build thermal models of Campi Flegrei caldera, Italy. Campi Flegrei experienced at least 4 major unrest episodes in the last decades. Our results indicate that the inflation and deflation of magmatic sources at the same location explain most deformation, at least since the build-up of the last 1538 AD eruption. However, such a repeated magma emplacement requires a persistently hot crust. Our thermal models show that this repeated emplacement was assisted by the thermal anomaly created by magma that was intruded at shallow depth ~3 ka before the last eruption. This may explain the persistence of the magmatic sources promoting the restless behaviour of the Campi Flegrei caldera; moreover, it explains the crystallization, re-melting and mixing among compositionally distinct magmas recorded in young volcanic rocks. Our model of thermally-assisted unrest may have a wider applicability, possibly explaining also the dynamics of other restless calderas.
许多火山口在几个世纪中表现出反复的不稳定。尽管这种独特的行为可能是由岩浆引起的，但目前还不了解其动力学机制，其动态仍然难以捉摸。为了更好地了解这些不安分的火山口，我们解释了意大利坎皮弗莱格雷雷火山口的变形数据并建立了热模型。坎皮弗莱格雷雷在过去几十年中至少经历了 4 次重大的不稳定事件。我们的结果表明，同一位置的岩浆源的膨胀和收缩解释了大部分变形，至少自上一次公元 1538 年喷发以来就是如此。然而，这种重复的岩浆安置需要一个持续较热的地壳。我们的热模型表明，这种重复的岩浆安置是由约 3000 年前最后一次喷发前浅层（~3 公里深）侵入的岩浆产生的热异常所辅助的。这可能解释了岩浆源的持续存在，促进了坎皮弗莱格雷雷火山口的不安分行为；此外，它还解释了在年轻火山岩中记录的成分不同的岩浆的结晶、再熔化和混合。我们的热辅助不稳定模型可能具有更广泛的适用性，可能也解释了其他不安分的火山口的动力学。
