3D Numerical Modeling of the Summit Lake Lava Flow, Yellowstone, USA

I A Tsepelev,O E Melnik,A T Ismail-Zadeh

doi:10.1134/s1069351321020129

Abstract

—Volcanic eruptions belong to the extreme events that change the Earth’s landscape and affect global climate and environment. Although special attention is given to super-eruptions, the non-explosive rhyolitic (highly viscous) eruptions and large lava flows are no less important. In this paper, we study an ancient lava flow with a volume of ~50 km3 in the Summit Lake region, Yellowstone, which is one of the best studied large intraplate igneous provinces. We develop three-dimensional (3D) numerical models of isothermal lava flow to analyze the influence of the underlying surface and lava flow viscosity on the advancement and duration of the flow. The modeled dynamics of flow propagation fairly well agrees with the measured values provided that the average angle of inclination of the underlying surface slightly differs from the present-day value (by ~1.3°) presumably due to the pressure change in the magma chamber during the eruption. With the increase in lava viscosity, the flow slows down and its thickness increases leading to a change in the flow morphology.

Highlights

Viscous rhyolitic lavas form flows varying in thickness from tens to hundreds of meters and typically having rather short, a few km, length
This hotspot is most likely to be responsible for the formation of melt feeding the super-eruptions and large lava flows, and, for the development of a volcanic province stretching over several states west of Wyoming as a result of the motion of the North American plate above the hotspot during the last 17 million years e.g., (Morgan, 1971; Smith et al, 2009; Camp et al, 2017)
Using the analytical solution of the problem of the viscous incompressible fluid flow on a flat surface (Huppert, 1982), Loewen et al (2017) have shown that the emplacement of rhyolite flow in the Summit Lake region (Fig. 1a) as a resulted of lava eruption 124 ka ago occurred over ~2– 5 years at temperatures of 800 C and high magma discharge rates above 100 m3 s–1

Summary

Introduction

Viscous rhyolitic lavas form flows varying in thickness from tens to hundreds of meters and typically having rather short, a few km, length. Seismic tomography reveals a low velocity channel beneath the Yellowstone National Park, which is interpreted as a mantle plume (Sigloch et al, 2008) This hotspot is most likely to be responsible for the formation of melt feeding the super-eruptions and large lava flows, and, for the development of a volcanic province stretching over several states west of Wyoming as a result of the motion of the North American plate above the hotspot during the last 17 million years e.g., (Morgan, 1971; Smith et al, 2009; Camp et al, 2017). These high discharge rates are, concomitant with low magma ascent rates (below 1 cm s–1) because lava erupted through a fissure with a length of about 6 km long and a wide cross-section area which allowed the eruption to remain effusive (non-explosive)

Methods

Results

Conclusion