Scarfì L, Aloisi M, Barberi G, Langer H
Istituto Nazionale di Geofisica e Vulcanologia - Osservatorio Etneo, Catania, Italy.
Sci Rep. 2023 Aug 10;13(1):12951. doi: 10.1038/s41598-023-39639-9.
Geophysical data provide the chance to investigate a volcano's dynamics; considerable information can especially be gleaned on the stress and strain patterns accompanying the internal processes and the effect of magma ascent on the main structures triggering earthquakes. Here, we analysed in detail the seismicity recorded over the last two decades on Etna volcano (southern Italy), focusing on earthquakes distribution and focal mechanism clustering; the ground deformation pattern affecting the volcanic edifice with the inflation and deflation phases was also examined. Analysed data were compared in order to shed light on possible relationships with the volcanic activity and to better understand the internal dynamics of the volcano over time. Significant steps during or shortly before major eruptions in the seismic strain release and ground deformation temporal series highlight a straightforward relationship between seismicity occurring at shallow level, inflation/deflation and volcanism. Furthermore, at depths greater than 5-7 km, down to about 20 km, the orientation of the P- and T-axes clearly indicate the existence of a pressure source in the central part of the volcano. All the results underline that the stress field related to the volcano plumbing system interferes with the regional field, partly overriding it.
地球物理数据为研究火山动力学提供了契机；尤其是可以获取大量有关伴随内部过程的应力和应变模式以及岩浆上升对引发地震的主要构造的影响的信息。在此，我们详细分析了过去二十年在意大利南部埃特纳火山记录到的地震活动，重点关注地震分布和震源机制聚类；还研究了影响火山体的地面变形模式及其膨胀和收缩阶段。对分析的数据进行了比较，以阐明与火山活动的可能关系，并更好地了解火山随时间的内部动力学。在主要喷发期间或之前不久，地震应变释放和地面变形时间序列中的显著变化突出了浅源地震活动、膨胀/收缩与火山活动之间的直接关系。此外，在深度大于5 - 7千米直至约20千米处，P轴和T轴的方向清楚地表明在火山中部存在一个压力源。所有结果都表明，与火山管道系统相关的应力场干扰了区域应力场，部分地覆盖了它。
