UNDERSTANDING LAVA LAKES USING A NOVEL RADAR ALTIMETER

Lead Research Organisation: University of Cambridge
Department Name: Geography

Abstract

We aim to investigate transient, oscillatory and secular behaviour related to the dynamics of magma degassing and transport, and reflected in the levels of lava lakes, and in the composition and fluxes of emitted gases and in other geophysical and geodetic parameters. We will achieve this through detailed studies of the lava lakes of two contrasting "laboratory volcanoes" (Kilauea and Erebus). While both volcanoes host lava lakes, their magma properties differ significantly in terms of composition, crystal content, viscosity and degassing styles. This will enable us to examine a variety of volcanic phenomena and to develop and evaluate hypotheses pertinent to understanding the behaviour of many open-vent volcanoes around the world.

Of particular importance to the project, we plan to acquire high-precision, high-temporal resolution and sustained measurements of lava lake level using an innovative and purpose-built radar instrument. This will be a novel adaptation of existing radar systems that have been used for other environmental applications, and builds from work on a prototype radar device that we are already designing and constructing ahead of our next field mission to Erebus volcano. The radar observations will be integrated, at the target volcanoes, with both operational and campaign measurements obtained from ultraviolet and infrared spectroscopy (for gas flux and composition), thermal imagers (for lake surface radiometry and velocimetry), gravimetry (for mass changes), continuous geodesy (to characterise ground deformation) and seismology. The new radar instrument will be integrated into the operational surveillance programme of the Hawaiian Volcano Observatory.

Our focus in the first half of the project will be on perfecting and installing the radar instrumentation. In the second half we will capitalise on the incoming datastreams, integrate them with our own and other ancillary observations of the target lava lakes, and use time-series analysis to identify temporal evolution of lava lake cycles and secular phenomena, and leads and lags between different parameters (e.g., lake level, gas flux, gas composition). This will help to tease out relationships and feedbacks between degassing, rheology, lake geometry and eruptive style (e.g., explosive vs. passive degassing at Erebus).

A key outcome of the project will be the development of hypotheses that explain the complex variations in lava lake level, gas flux and chemistry, mass change and surface deformation that we will have documented in the field. We expect the observed variability and contrasting dynamic regimes to represent both shallow (conduit and lava lake) and deeper (reservoir) processes.

A key to the ethos of the project is its combination of expertise in radar instrumentation (UCL) and volcanology (Cambridge), and the close collaboration of UK project members with partners in the USA (the US Geological Survey-Hawaiian Volcano Observatory, and the Mount Erebus Volcano Observatory, which operates from New Mexico Tech.). This is an ambitious project through which we hope to transform aspects of our understanding of magmatic processes, thanks to the planned synergy of electrical engineering, field science, and sophisticated data processing and time-series analysis. We aim to recruit a PhD student through the Cambridge-NERC Earth System Science DTP to develop theoretical aspects of lava lake fluid dynamics. The student would work closely with the PI and named researcher (Dr. Nial Peters).

Planned Impact

User engagement is an intrinsic part of our project because of the synergy of research and operational monitoring that will be achieved with the U.S. Geological Survey - Hawaiian Volcano Observatory (HVO).
We identify three groups of beneficiaries of our research:

(i) The USGS-HVO will benefit from the installation of a sophisticated and bespoke radar altimeter, which will enable operational surveillance of the lava lake level at Kilauea. This will contribute to assessment of volcanic activity, and thereby to HVO's role in risk reduction (up to 3 million people visit the Hawai'i Volcanoes National Park annually). The shift in activity to the summit crater of the volcano has resulted in closure of part of the National Park to the public but visitors can still be exposed to hazards associated with acid gas and aerosol emissions from the lava lake depending on prevailing winds. Because lava lake level is such a key descriptor of the state of the magmatic system, the installation of the proposed radar device will represent a significant advance in the operational work of HVO.

(ii) The wider (international) volcano observatory community, especially those concerned with monitoring basaltic volcanoes, stands to benefit from increased knowledge of magmatic processes, in addition to developments in interpretation of multi-parameter datasets. These advances will arise through the development and testing of hypotheses throughout the project, and the refinement of models to explain and interpret cycles and transitions that characterise many aspects of "open-vent" volcanic behaviour.

(iii) Industrial beneficiaries are expected from within the radar community, including civil and defence companies that UCL already collaborates with on other projects. The technology developed by the project will enable high precision range measurements using novel cross-correlation techniques and allow the acquisition of continuous time-series data sets. The project will greatly contribute to the skill set and experience of the named Researcher (Dr. Nial Peters), who will gain expertise in radar engineering, time-series analysis, fieldwork planning and making international collaborations work. This combination of skills in addition to the opportunities for professional networking across a range of research areas and institutions will build further his expertise and recognition ahead of the next stage of his research career.

Publications

10 25 50
 
Description Successful deployment of prototype radar devices for monitoring lava lake height at Mount Erebus and Kilauea volcanoes. Progress made with data analysis. First paper published reporting operational principles, data analysis approaches, and examples of lava lake height variation observed at Mount Erebus.
Exploitation Route Work in progress but the radar device is already being used for other applications.
Sectors Electronics,Environment

 
Description USGS-HVO 
Organisation US Geological Survey
Department USGS Hawaiian Volcano Observatory
Country United States 
Sector Public 
PI Contribution Planning fieldwork for summer 2017 - more to report next year
Collaborator Contribution Planning fieldwork for summer 2017 - more to report next year
Impact Planning fieldwork for summer 2017 - more to report next year
Start Year 2016
 
Title EredarII 
Description Low-power, X-band FMCW radar system. Although primarily designed for lava lake monitoring, the highly-configurable design of the hardware has meant that the system has also been used for avalanche monitoring. 
Type Of Technology Detection Devices 
Year Produced 2017 
Impact The radar has allowed us to make the first long-duration study of the level of Erebus volcano's active lava lake. Initial analysis of these data suggest that previous theories about the mechanisms driving the lake are incorrect. 
 
Description HVO Volcano Watch article 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Contribution of an article to the Hawaiian Volcano Observatory's online weekly newsletter "Volcano Watch" detailing the fieldwork conducted in January 2018 using the new radar system developed during this project.
Year(s) Of Engagement Activity 2018
URL https://volcanoes.usgs.gov/observatories/hvo/hvo_volcano_watch.html
 
Description Hertforshire Geological Society talk 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Lecture and general discussion / questions session at meeting of local Geology interest group. Talk was well received and a request was made for participation in future outreach events run by the group.
Year(s) Of Engagement Activity 2017
URL http://www.hertsgeolsoc.ology.org.uk/index.htm
 
Description Home Counties Regional Group Meeting 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Talk with discussion/questions session afterwards at Home Counties Regional Group (Geology interest group) meeting. Discussion session was lively with several audience members requesting further information. A follow-up article is due to appear in the group's newsletter.
Year(s) Of Engagement Activity 2018