DTM Takes to Stromboli for Ambitious Volcanology Research
DTM went without volcanologists for two weeks in mid May 2018, as the volcanology team traveled to Stromboli Volcano in Italy for an ambitious field experiment that combines infrasound, seismicity, gravity, and gas emission data to better understand shallow volcanic explosions.
The project, led by DTM's NSF Postdoctoral Fellow Kathleen McKee and including staff scientists Diana Roman and Hélène Le Mével, will for the first time quantitatively link precursory seismic and tilt activity to volcanic eruption acoustic and gas signals. The findings will contribute to the work of volcano monitoring techniques worldwide to reduce threats to communities located near active volcanoes.
"It will be the first time we quantitatively investigate the link between precursory volcano inflation and the explosion signal to determine whether we can say something like, 'the bigger the tilt signal, the bigger the explosion,'" McKee said. "That seems to make intuitive sense, but it may not always be the case."Stromboli Volcano, May 9, 2018. Picture by Hélène Le Mével, DTM.
Volcanos often "inflate" prior to eruptions due to magma and gas rising to the shallow edifice. This deformation can be observed at a variety of time scales (on the order of decades to hundreds of seconds). Scientists use instruments such as satellites, GPS, and tiltmeters to measure changes in volcanos' edifices.
McKee's research focuses on volcano acoustics, particularly on infrasound: sound waves at frequencies below what humans can hear. Her goal is to use her expertise in infrasound produced by volcanic activity to connect what scientists know about inflation signals with the amount of material erupted during a volcanic explosion.
"We deployed gas instrumentation in order to compare the infrasound and seismically derived gas volumes with the gas volume determined from gas observations," McKee said. "We will get at the volume of gas that comes into the shallow subsurface and is then released for each individual explosion."Left: DTM volcanologists Diana Roman (left) and Kathleen McKee at Stromboli installing one of the Carnegie Quick Deploy Boxes developed with support of the Brinson Foundation. Right: Hélène Le Mével doing a maintenance visit to the gravimeter instrument used at Stromboli. Pictures by Hélène Le Mével, DTM.
Volcano inflation is measured using in-situ and remote sensing tools. Using these deformation signals, scientists can quantify magma volumes in the subsurface of a volcanic system. But with large deformation signals usually followed by large-scale eruptions, the acoustics are highly complex. Volcanologists are currently working to quantify erupted material in large-scale eruptions.
"Using volcano infrasound, we've been able to quantify flow rate of simple explosions, or in other words, determine how much material comes out based on the sound waves produced," McKee said. "The idea of my project is to scale down to something we know we can do with infrasound—quantify the small inflation using seismic and tilt data and the explosion using infrasound and gas data."At the summit vent area of Stromboli Volcano, five active vents are intermittenly producing ash plumes, bombs or degassing. Picture by Hélène Le Mével, DTM.
McKee's team deployed seismometers and infrasound sensors, as well as a MultiGas, gravimeter, Fourier Transform Infrared (FTIR), and Forward Looking Infrared (FLIR) instrument at Stromboli Volcano, Italy. It was one of the first large-scale deployments of the Carnegie Quick Deploy Boxes (QDBs) developed by DTM.
The team also involved scientists from the University of Alaska Fairbanks, where McKee did her doctoral research; the Michigan Technological University, where McKee did her master's research; the University of Florence; and the University of Palermo.
Learn more about McKee's research and fieldwork via YouTube: https://www.youtube.com/watch?v=odJEtYAzMuE&feature=youtu.be
—Roberto Molar Candanosa