Tephra Dispersal From Basaltic Plinian Eruptions: The Case Study of the Fontana Lapilli Scoria-Fall Deposit (>20ka BP), Masaya Caldera Complex, Nicaragua

University Of South Florida, Tampa FL

Investigators

Abstract

EAR-0310096 Bonadonna Highly explosive basaltic eruptions constitute an important hazard to society that is often underestimated. Some are now recognized as extremely violent with destructive effects covering tens of thousand of square kilometers. Examples include the 122 BC eruption of Etna (Italy), the 1790 AD Keanakakoi eruption of Kilauea (Hawaii), the 1886 eruption of Tarawera (New Zealand) and the Fontana Lapilli eruption of Masaya volcano (Nicaragua) (>20ka BP). The Fontana Lapilli eruption produced the largest scoria-fall deposit known, and characterization of this deposit is crucial to constraining the magnitude and intensity of such eruptions. This project will (i) remap the tephra-fall deposit, (ii) investigate new techniques for understanding grain-size distribution using exponential and power-law methods to estimate deposit volume, (iii) infer the column height and (iv) simulate the mechanisms of scoria-fall using a numerical model for tephra dispersal from strong plumes.