# Periodic outgassing as a result of unsteady convection in Ray Lava Lake, Mount Erebus, Antarctica

## TL;DR

This study uses numerical simulations to show that periodic outgassing pulses in Ray Lake, Mount Erebus, can result from internal convective dynamics rather than periodic magma influx, challenging previous assumptions about conduit influence.

## Contribution

It demonstrates that internal convection within the lava lake can produce observable periodic outgassing without periodic input from the conduit, offering a new perspective on volcanic surface signals.

## Key findings

- Periodic surface behavior can arise from convective lake dynamics.
- Internal convection can mimic conduit-driven periodicity.
- Surface signals may not directly reflect conduit processes.

## Abstract

Persistently active lava lakes show continuous outgassing and open convection over years to decades. Ray Lake, the lava lake at Mount Erebus, Ross Island, Antarctica, maintains long-term, near steady-state behavior in temperature, heat flux, gas flux, lake level, and composition. This activity is superposed by periodic small pulses of gas and hot magma every 5-18 minutes and disrupted by sporadic Strombolian eruptions. The periodic pulses have been attributed to a variety of potential processes including unstable bidirectional flow in the conduit feeding the lake. In contrast to hypotheses invoking a conduit source for the observed periodicity, we test the hypothesis that the behavior could be the result of dynamics within the lake itself, independent of periodic influx from the conduit. We perform numerical simulations of convection in Ray Lake driven by both constant and periodic inflow of gas-rich magma from the conduit to identify whether the two cases have different observational signatures at the surface. Our simulations show dripping diapirs or pulsing plumes leading to observable surface behavior with periodicities in the range of 5-20 minutes. We conclude that a convective speed faster than the inflow speed can result in periodic behavior without requiring periodicity in conduit dynamics. This finding suggests that the surface behavior of lava lakes might be less indicative of volcanic conduit processes in persistently outgassing volcanoes than previously thought, and that dynamics within the lava lake itself may modify or overprint patterns emerging from the conduit.