The volcanic explosivity index (VEI) an estimate of explosive magnitude for historical volcanism

TLDR

Understanding the frequencies of highly, moderately, and non‑explosive eruptions is important for volcano studies, yet historical records are incomplete, with only the largest eruptions documented back to the early 19th century and few events preserved in the geologic record, making post‑hoc augmentation impossible. The study proposes the Volcanic Explosivity Index (VEI) as a semi‑quantitative estimate of past explosive eruption magnitude to address this data gap. The VEI is derived by combining limited historical and geological data into a composite estimate, and has been assigned to over 8000 eruptions, with a complete list provided in a companion document. The VEI catalog now contains over 8000 historic and prehistoric eruptions, offering a comprehensive resource for evaluating past volcanism.

Abstract

Knowledge of the frequencies of highly explosive, moderately explosive, and nonexplosive eruptions would be useful in a variety of volcano studies. Historical records are generally incomplete, however, and contain very little quantitative data from which explosive magnitude can be estimated. Only the largest eruptions have a complete record back to the early 19th Century; other important explosive events went unrecorded prior to about 1960. Only a handful of the very biggest eruptions are represented in the geologic record, so it will be impossible to augment historical records post facto. A composite estimate of the magnitude of past explosive eruptions, termed the Volcanic Explosivity Index (VEI), is proposed as a semiquantitative compromise between poor data and the need in various disciplines to evaluate the record of past volcanism. The VEI has been assigned to over 8000 historic and prehistoric eruptions, and a complete list is available in a companion document.