The distribution and development of eruptive centres and lava flow-field characteristics at Somma-vesuvius, Italy

  • Sarah Krystyna Brown

    Student thesis: Doctoral Thesis


    Vesuvius in Southern Italy is among the most densely populated active volcanoes on Earth. Although famous for its Plinian eruption that destroyed Pompeii and Herculaneum in AD 79, its recent activity, between 1631 and 1944, was primarily effusive. Data from field studies, analogue modelling and historical accounts are here combined to investigate Vesuvius’ activity during this latest eruptive phase and to identify behavioural trends of value for enhancing emergency responses during future unrest.

    The focus of this study is on the activity of 1631-1944, and data have been compiled for183 eruptions during this period. Further data regarding earlier flank eruptions have been incorporated permitting a more comprehensive examination of these infrequent events. Such flank vents have been concentrated on the southern flanks at about 300m above sea level and a mean distance of 4.2 km from the summit. A submarine pit crater,newly correlated here with the 1861 eruption, highlights the potential for vents to format almost twice the mean distance from the summit and further than previously considered. Analogue studies of magma injection, using a gelatine model, have shown that the vent distribution is consistent with a regional stress field modified by gravitational stresses due to the size and shape of the volcanic edifice.

    The study of the 1631 to 1944 lava flow-fields shows that lavas from flank vents reached similar lengths to summit and lateral vent flow-fields, all with mean lengths around 4km.Over half of all lava flow-fields extended to beyond 4km from the crater, and so threatened the principal settlements around the foot of the volcano. The flow-fields had typical surface areas of less than 5 km2, and approximately a third reached their maximum length within a week. Flank eruptions normally occurred when the summit crater was full of lava and were commonly preceded by three days of elevated seismicity. Such events can thus potentially be forecast with at least a 24-hour warning and, even after an eruption has begun, several days may be available before a settlement is threatened. The design of an effective emergency response to future effusions is thus a feasible objective.
    Date of AwardSept 2013
    Original languageEnglish
    SupervisorCarmen Solana (Supervisor) & Christopher R. J. Kilburn (Supervisor)

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