Low-cost GNSS as a tool for near real-time monitoring of volcanic surface deformation using bespoke geodetic networks

The proliferation of low-cost Global Navigation Satellite System (GNSS) receivers with subdecimetre precision has occurred as a critical component of autonomous vehicle development and preparedness for mass-market. This hardware revolution provides geodesists with the opportunity to deploy GNSS receivers at low-cost, as bespoke, semipermanent, long-duration networks to discern surface deformation at high temporal resolution in support of specific science cases. In parallel, the revolution of the Internet-of-Things and continued reduction in data transfer costs through GSM networks makes it possible to stream GNSS data from deployment locations in near real-time at low cost. The upshot is a feasible replication of much of the functionality of top of the range GNSS receivers used as Continuously Operating Reference Stations (CORS) at relatively low-cost, with some reduction in accuracy and precision. We see the use of low-cost GNSS as a complimentary geodetic approach to the use of CORS networks and campaign surveys. Lowcost hardware is advantageous as it can be deployed to operate continually in locations where it would be impractical to use expensive ‘off the shelf’ solutions, such as where equipment is likely to be destroyed, or where it may perilous to manually retrieve hardware and recorded data. The cost reduction of low-cost GNSS hardware means denser networks of receivers can be deployed at specific budgets, maximising spatial coverage and resolution to help better characterise underlying processes. We present examples of the use of lowcost GNSS to measure deformation during the 2016 Central Italy seismic sequence and following the 2016 Kaikoura earthquake. We will discuss specific relevance to volcanic deformation using developments of a volcano-specific deployment.