Parameters Controlling the Eruption Frequency of Long-Lived Felsic Magmatic Systems: An Example From the Milos Volcanic Field (Greece)

Abstract

The mechanism controlling the volcanic eruption frequency is yet poorly understood. The key to a better understanding this mechanism comes from integrating accurate geochronology with numerical models. In many silicic volcanic systems, the eruption frequency is studied for short timescales of <500 kyr. Here, we combine two published numerical models (Caricchi et al., 2014, https://doi.org/10.1038/ngeo2041; Degruyter & Huber, 2014, https://doi.org/10.1016/j.epsl.2014.06.047) to improve our understanding of the eruption frequency in a long-lived (>3 Ma) felsic magmatic system, the Milos volcanic field. We use the published Milos geochronological data as input into the Caricchi et al. (2014, https://doi.org/10.1038/ngeo2041) model to derive average magma supply rates (Qav) and eruptible volumes. These two parameters are then used in the Degruyter and Huber (2014, https://doi.org/10.1016/j.epsl.2014.06.047) model to compute the chamber growth rate (Gmc) for the Milos magmatic system. The results of the Caricchi et al. (2014, https://doi.org/10.1038/ngeo2041) model indicate that the time intervals between magma pulses into the subvolcanic reservoir (ti) and Qav are the key parameters controlling the eruption frequency. During the time intervals of 1.48–1.04 and 0.97–0.63 Ma the ti is longer than 1000 years and the volcanic quiescence periods are longer than 350 kyr. Furthermore, these periods are characterized by low values for Qav (≤0.001 km3 · yr−1) and Gmc (<0.0001 km3 · yr−1). In contrast, during the time intervals of 2.0–1.5 and 0.60–0.06 Ma, the ti is shorter (<0.5 kyr) and the values for Qav (>0.001 km3 · yr−1) are higher corresponding to frequent eruptions.