Trasatti E, Acocella V, Di Vito M A, Del Gaudio C, Weber G, Aquino I, Caliro S, Chiodini G, de Vita S, Ricco C, Caricchi L
Istituto Nazionale di Geofisica e Vulcanologia Italy.
Department of Earth Sciences Università degli Studi di Roma Tre Rome Italy.
Geophys Res Lett. 2019 Dec 28;46(24):14421-14429. doi: 10.1029/2019GL085371. Epub 2019 Dec 23.
Transient seismicity at active volcanoes poses a significant risk in addition to eruptive activity. This risk is powered by the common belief that volcanic seismicity cannot be forecast, even on a long term. Here we investigate the nature of volcanic seismicity to try to improve our forecasting capacity. To this aim, we consider Ischia volcano (Italy), which suffered similar earthquakes along its uplifted resurgent block. We show that this seismicity marks an acceleration of decades-long subsidence of the resurgent block, driven by degassing of magma that previously produced the uplift, a process not observed at other volcanoes. Degassing will continue for hundreds to thousands of years, causing protracted seismicity and will likely be accompanied by moderate and damaging earthquakes. The possibility to constrain the future duration of seismicity at Ischia indicates that our capacity to forecast earthquakes might be enhanced when seismic activity results from long-term magmatic processes, such as degassing.
除了火山喷发活动外，活火山的短暂地震活动也构成重大风险。这种风险源于一种普遍观念，即火山地震活动无法预测，即使从长期来看也是如此。在此，我们研究火山地震活动的本质，试图提高我们的预测能力。为此，我们考察了意大利伊斯基亚火山，该火山在其隆起的复活地块沿线遭受了类似地震。我们表明，这种地震活动标志着复活地块长达数十年沉降的加速，这是由先前导致隆起的岩浆脱气驱动的，这一过程在其他火山未被观测到。脱气将持续数百至数千年，导致长期地震活动，并可能伴随中度和破坏性地震。限制伊斯基亚未来地震活动持续时间的可能性表明，当地震活动是由长期岩浆过程（如脱气）引起时，我们预测地震的能力可能会增强。
