Low-cost, ultra-sensitive gravimeter for early detection of volcanic activity uses MEMS technology
10 Dec 2021
A new device being developed by University of Glasgow in collaboration with a leading product design house can detect subtle changes in local gravity and provide an early warning device for volcanic eruptions. The Glasgow team's system uses MEMS (Micro-electromechanical Systems) technology and multiple devices can be deployed out in the field simultaneously, creating what is known as a gravity imager.
As recent events in Indonesia and La Palma have shown there are a significant number of live volcanoes throughout the world. If eruptions can be detected early enough it can help save lives. Leading product design house Wideblue has been working with the University of Glasgow (UoG) to develop a gravimeter which can detect subtle changes in local gravity caused by magma flow which could predict when a volcanic eruption could be expected.
The device has been designed to measure the flow of lava (shifting of mass) at the summit of Mount Etna in Sicily. It deploys MEMS (Micro-electromechanical Systems) technology commonly used in mobile phones (as accelerometers) to produce an ultra-sensitive gravimeter to measure tiny changes in local gravity. However, the silicon springs used in the device are ten times thinner than a human hair which makes the accelerometer highly sensitive to any changes in gravity.
Barry Warden, managing director, Wideblue said: "Wideblue's role in the project was to develop a self-levelling mechanism to allow remote levelling adjustment of the device and also create a watertight enclosure to protect the electronics and MEMs from moisture. In addition, we created an insulation system to avoid the MEMs being subject to temperature fluctuations from the external harsh environment."
He added: "The first prototype device went live on Mont Etna on 9 August this year and the plan is to create an array of multiple devices to gather data across a large area. The overall plan is to have a number of devices active early next year.
Dr Karl Toland, from the University of Glasgow, adds: "The use of gravimetry to detect changes in subsurface masses, allowing us to understand the processes that involve deep fluids, is an extremely effective geophysical tool. However, its utilisation is severely limited due to the high upfront costs of commercial devices and the practicality of taking measurements over a large surface area with a single device.
"Members of the Institute for Gravitational Research at the University of Glasgow have developed a low-cost gravimeter with the goal of changing the paradigm for gravimetry measurements, known as Wee-g. The low cost of a Wee-g compared to commercial gravimeters allow for multiple Wee-g devices to be deployed out in the field simultaneously, creating what is known as a gravity imager. This will provide imaging of gravity changes with unparalleled spatio-temporal resolution across the area of interest."