Radar Altimetry as a Robust Tool for Monitoring the Active Lava Lake at Erebus Volcano, Antarctica

Abstract

The level of lava within a volcanic conduit reflects the overpressure within a connected magma reservoir. Continuous monitoring of lava level can therefore provide critical insights into volcanic processes and aid hazard assessment. However, accurate measurements of lava level are not easy to make, partly owing to the often dense fumes that hinder optical techniques. Here we present the first radar instrument designed for the purpose of monitoring lava level and report on its successful operation at Erebus volcano, Antarctica. We describe the hardware and data‐processing steps followed to extract a time series of lava lake level, demonstrating that we can readily resolve ∼1 m cyclic variations in lake level that have previously been recognized at Erebus volcano. The performance of the radar (continuous, automated data collection in temperatures of around −30 °C) indicates the suitability of this approach for sustained automated measurements at Erebus and other volcanoes with lava lakes.

Harnessing Erebus volcano's thermal energy to power year-round monitoring

“…As technology continues to develop, there will be an increasing number of low-power monitoring devices that could be powered by TEG devices. For example, the Erebus radar system used to monitor to the level of the active lava lake initially consumed ~21 W (Peters et al 2018); however, recent hardware upgrades have reduced this to ~3 W, with further reductions possible by lowering the acquisition rate. Although still considerably higher than the power output of our prototype generator, the power requirements of the radar are now approaching what could be achieved with a small network of Seebeck generators.…”

“…Despite the development of several autonomous monitoring systems (e.g. Peters et al 2014aPeters et al , 2018, the lack of a reliable over-winter power system has so far prevented year-round data acquisition at the crater rim of Erebus.…”

mGEODAR—A Mobile Radar System for Detection and Monitoring of Gravitational Mass-Movements

“…As Long and Reschovsky [20] report, a digital triggering of a ramp start can improve the phase stability greatly. The EREDAR system utilizes digital triggering of the DDS and the acquisition system [10], and we will implement a similar chirp control for the research mode in a next step.…”

“…The mGEODAR (mobile GEODAR) is an X-band FMCW-type radar with a centre carrier frequency of 10.4 GHz and 400 MHz bandwidth. The RF circuitry of mGEODAR is based on a previously developed radar EREDAR (Erebus radar), which is a purpose-built radar for monitoring the lava lake level in the Erebus volcano, Antarctica [10]. Although the system requirements to capture the variations of a lava lake in the range of centimetres per minute are quite different compared to the rapid movements of gravitational mass-movements, the digital nature of the signal generation enables the flexibility for various usage.…”

“…Although the system requirements to capture the variations of a lava lake in the range of centimetres per minute are quite different compared to the rapid movements of gravitational mass-movements, the digital nature of the signal generation enables the flexibility for various usage. Most of the radar hardware descriptions resemble EREDAR [10] and are only summarised here. First, we describe the radar hardware with settings of the current system featuring transmit frequencies from 10.2 GHz to 10.6 GHz.…”