Effusion Rate Evolution During Small‐Volume Basaltic Eruptions: Insights From Numerical Modeling. Issue 6 (3rd June 2020)

• Record Type: Journal Article
• Authors: Aravena, A.; Cioni, R.; Coppola, D.; de' Michieli Vitturi, M.; Neri, A.; Pistolesi, M.; Ripepe, M.
• Is Part Of: Journal of geophysical research. Volume 125:Issue 6(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-06-03
• Subjects: volcanology -- effusive eruptions -- basaltic magmas -- effusion rate -- numerical modeling -- conduit modeling; Geomagnetism -- Periodicals; Geochemistry -- Periodicals; Geophysics -- Periodicals; Earth sciences -- Periodicals; 551.1
• DOI: 10.1029/2019JB019301
• Languages: English
• ISSNs: 2169-9313

Abstract

Abstract: The temporal evolution of effusion rate is the main controlling factor of lava spreading and emplacement conditions. Therefore, it represents the most relevant parameter for characterizing the dynamics of effusive eruptions and thus for assessing the volcanic hazard associated with this type of volcanism. Since the effusion rate curves can provide important insights into the properties of the magma feeding system, several efforts have been performed for their classification and interpretation. Here, a recently published numerical model is employed for studying the effects of magma source and feeding dike properties on the main characteristics (e.g., duration, erupted mass, and effusion rate trend) of small‐volume effusive eruptions, in the absence of syn‐eruptive magma injection from deeper storages. We show that the total erupted mass is mainly controlled by magma reservoir conditions (i.e., dimensions and overpressure) prior to the eruption, whereas conduit processes along with reservoir properties can significantly affect mean effusion rate, and thus, they dramatically influence eruption duration. Simulations reproduce a wide variety of effusion rate trends, whose occurrence is controlled by the complex competition between conduit enlargement and overpressure decrease due to magma withdrawal. These effusion rate curves were classified in four groups, which were associated with the different types described in the literature. Results agree with the traditional explanation of effusion rate curves and provide new insights for interpreting them, highlighting the importance of magma reservoir size, initial overpressure, and initial width of the feeding dike in controlling the nature of the resulting effusion rate curve. Key Points: The effects of magma source and feeding dike properties on the evolution of small‐volume effusive eruptions are studied numerically Total erupted mass is mainly controlled by magma reservoir conditions (in particular, dimensions and overpressure) prior to the eruption Different types of effusion rate curves were modeled, classified, and compared with the effusion rate trends defined in the literature